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~- " .. <~ ·~·:r~~
~~ REPORT NO~
.. ~ UCBIEERC·86106
May 1986
PB87124210 1111111 111111111111111111 111111
EARTHQUAKE ENGINEERING RESEARCH CENTER
DETERMINATION OF PENETRATION RESISTANCE FOR COARSE·GRAINED SOILS USING THE BECKER HAMMER DRILL by
LESLIE F. HARDER, Jr.
H. BOLTON SEED
A report on research sponsored by the National Science Foundation
COLLEGE OF ENGINEERING
UNIVERSITY OF CALIFORNIA . Berkeley, California REPRODUCED BY, ~
U.S. Department of Commerc.a National Technicallnronnation Service
Springfield, Virginia 22161
· GENERAL DISCLATh1ER
This document may have problems that one or more of the following disclaimer statements refer to: '
• This document has been reproduced from the best copy furnished by the sponsoring agency. It is being released in the interest of making available as much infonnation as possible.
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50272-101
REPORT DOCUMENTATION T I. RE~~ ~Oi PAGE I /)/\r /E/!.)(:" ?60/C/
2. 3. Recipient'. Acce •• lon No.
PBS 7 1 2 4 2 1 0 lAS 4. Title and Subtitle I
Determination of Penetration Resistance For Coarse-Grained 5. Rlport O.te
May, 1986 Soils Using The Becker Hammer Drill
7. Author(s)
Leslie F. Harder, Jr. and H. Bolton Seed ,. Performing Organization Name and Address
Earthquake Engine~ring Research Center University of California 1301 ~outh 46th Street Richmond, California 94304
12. Sponsoring Organization Name and Address
National Science Foundation 1800 a. Street, N.W. Washington, D.C. 20550
15. Supplementary Notes
16. Abstract (Limit: 200 words)
L Performing Orwanlzlltion Rept. No.
I Jr.R / F FRr.-86 /06 10. Project/T .. k/Work Unit No.
11. Clit()tt~C) or Grant(G) No.
(C) r~SF No. CEE-84-12366
(G)
13. Type of Report & Period Covered
An investigation has been conducted on the use of a large dynamic penetrometer, developed by Becker Drills, Ltd., for determining the penetration resistance of gravelly soils.
The results show that variations in drilling equipment and procedures significantly influence the Becker Penetration Resistance. To reduce the potential for variability in test results, a set of procedures is recommended as a standard.
Using the recommended procedures, a new correlation between Becker Penetration Test resistance and Standard Penetration Test resistance has been developed. This new correlation has much less scatter than previous correlations and, by using data and experience developed in sands using the Standard Penetration Test, it provides a meaningful method for evaluating the probable behavior of gravelly deposits.
17. Document Analysis a. Descriptors
dynamic penetrometer penetration gravelly soi 1 s
earthquake seismic
b. Identifiers/Open·Ended Terms
Becker Penetration Resistance Standard Penetration Test
c. COSATI Field/Group
IL Availability Stateme":
Release Unlimited
(See ANSI-Z39.18)
1'. Security Cle •• (Thl. Report)
IlnLl ac; c;; f; prj
20. Security Cia .. (Thl. Pege)
Uncl ass ifi ed
21. No. of Pages
1 i./. g 22. Price
OPTIONAL FORM 272 (4-77) (Formerly NTlS-3s) Department of Commerce
EARTHQUAKE ENGINEERING RESEARCH CENTER
DETERMINATION OF PENETRATION RESISTANCE FOR COARSE-GRAINED SOILS
USING THE BECKER HAMMER DRILL
by
Leslie F. Harder, Jr.
and
H. Bolton Seed
Report No. UCB/EERC-86-06
May 1986
A report on research sponsored by the National Science Foundation
College of Engineering
University of California
Berkeley, California
Abstract
An investigation has been conducted on the use of a large dynamic
penetrometer, developed by Becker Drills, Ltd., for determining the
penetration resistance of gravelly soils.
The results show that variations in drilling equipment and procedures
significantly influence the Becker Penetration Resistance. To reduce the
potential for variability in test results, a set of procedures is recom
mended as a standard.
Using the recommended procedures, a new correlation between Becker
Penetration Test resistance and Standard Penetration Test resistance has
been developed. This new correlation has much less scatter than previous
correlations and, by using data and experience developed in sands using
the Standard Penetration Test, it provides a meaningful method for
evaluating the probable behavior of gravelly deposits.
ii
Acknowledgements
This investigation was supported by Grant No. CEE-84-l2366 from the
National Science Foundation. The support of the Foundation for this research
is greatly appreciated.
Information on previous Becker Penetration Test studies was kindly pro
vided by O. Farris, M. Allen, L. Walker, W. Jones, I. Staal, and T. Dunne.
Additional information regarding the diesel hammer operation was provided by
Tony Last. Permission to perform the field studies and access at the various
test sites were generously provided by Mr. L. H. Huntington, the California
Department of Water Resources, the United States Navy, the Colorado Sand and
Gravel Company, and the Big Lost River Irrigation District. Assistance ~n
facilitating the field studies was provided by Cliff Lucas, Dean Smith, G.
Reyes, D. Haynosch, R. Monroe, E. Shoebotham, D. Jensen, and R. Lundy. Addi
tional assistance in handling field samples was provided by W. Hammond,
R. Torres, D. Najima, R. Johnson, and C. Moody.
Finally we wish to acknowledge the generous help and cooperation
provided by Becker Drills, Inc. The careful attention to details from
Drillers Ken Arnold and Bill Jeskey is greatly appreciated.
CHAPTER 1
CHAPTER 2
CHAPTER 3
CHAPTER 4
REFERENCES
APPENDIX
TABLE OF CONTENTS
INTRODUCTION
HISTORY OF THE BECKER PENETRATION TEST
Equipment
Becker Penetration Test
FIELD STUDIES OF VARIABLES AFFECTING THE RESULTS OF
iii
Page No.
1
6
6
9
BECKER PENETRATION TESTS 21
General 21
Test Sites 22
Salinas Test Site, California 22
Thermalito Test Site 27
San Diego Test Site 30
Denver Test Site 32
Mackay Dam Test Site 35
Effect of Closed vs. Open-Bits on Becker Blowcount 35
Effect of Diesel Hammer Energy on Becker Blowcount 49
Effect of Blower and/or Reduced Throttle 57
Evaluation of Energy Effects 79
Effect of Elevation on Energy and Bounce Chamber Pressure 83
Adoption of a Calibration Combustion Rating Curve 88
Effect of Drill Rig Type on Becker Blowcount 96
Effect of Casing Size on Becker Blowcount 104
Effect of Casing Friction on Becker Blowcount 106
DEVELOPMENT OF A CORRELATION BETWEEN BECKER A-ND SPT BLOWCOUNTS
DERIVATIONS OF RELATIONSHIPS BETWEEN DIESEL HAMMER ENERGY AND BOUNCE CHAMBER PRESSURE
110
116
118
Fig. No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
LIST OF FIGURES
Photograph of Becker Hammer Drill Rig
Schematic Diagram of Becker Sampling Operation
Reverse Circulation Process Used with Becker Hammer Drill and Open Drive Bits (adapted from Becker Drills, Inc. literature)
Typical Drill Bits Used with Becker Hammer Drill Rigs
Photograph Comparing 2-inch O.D. SPT Sampling Shoe with 6 SiB-inch O.D. Crowd-out Becker Drill Bit
Correlation Between Becker and SPT Blowcounts Developed from Canadian Data Obtained from Becker Drills, Inc. Files
Correlation Between Becker and SPT Blowcounts Developed by Sergent, Hauskins and Beckwith (1973)
Correlations Between Becker and SPT Blowcounts Developed by Geotechnical Consultants, Inc. (1981, 1983)
Correlation Between Becker and SPT Blowcounts Developed by Jones and Christensen (1982)
Previous Correlations Between Becker Blowcount and SPT B1owcount
General Layout of Borings and Soundings at Salinas Test Site
Gradation Curves for Becker Samples Obtained at the Salinas Test Site
General Layout of Borings and Soundings at Thermalito Test Site
Gradation Curves for Becker Samples Obtained at the Thermalito Test Site
15 General Layout of Borings and Soundings at San Diego Test Site
16 Photographs Illustrating Denver Test Site and Materials
17 General Layout of Becker Soundings at Denver Test Site
iv
Page No.
7
8
10
11
12
14
15
16
17
19
24
26
28
29
31
33
34
Fig. No.
18
19
20
21
22
23
24
25
26
27
General Layout of Becker Soundings at Mackay Test Site
Uncorrected Blowcounts from SPT and Closed Bit Becker Penetration Tests Performed at the San Diego Test Site
Comparison of Uncorrected Becker Blowcounts from Open and Closed Bit Penetration Tests Performed at the San Diego Test Site
Uncorrected Blowcounts from SPT and Becker Penetration Tests Performed at the Salinas Test Site
Uncorrected Blowcounts from SPT and Becker Penetration Tests Performed at the Thermalito Test Site
Comparison of SPT Blowcount Performed Through the Becker Casing with SPT Blowcounts Performed in Mud-filled Rotary Boreholes
Comparison of Uncorrected Becker Blowcounts from 6.6-inch Open and Closed Bit Soundings Performed at the Denver Test Site
Comparison of Uncorrected Becker Blowcounts from 5-5-inch Open and Closed Bit Soundings Performed at the Denver Test Site
Effect of Bit Diameter and Configuration on Becker Blowcount
Comparison of Uncorrected Becker Blowcounts from 6.6-inch Open and Closed Bit Soundings Performed at the Hackay Test Site
28 ICE Model 180 Diesel Pile Hammer (adapted from ICE literature)
29
30
31
32
Operational and Potential Energy Characteristics of Diesel Pile Hammer Used on Becker Drill Rigs
Monitoring Gage for Bounce Chamber Pressure (adapted from ICE literature)
Idealization of Relationship Between Becker Blowcount and Bounce Chamber Pressure
Relationship Between Becker Blowcount and Bounce Chamber Pressure for Full Throttle Combustion Conditions at the Salinas Test Site
v
Page No.
36
38
39
40
41
43
44
45
46
47
51
52
53
54
56
Fig. No.
33
34
35
36
37
38
39
40
41
42
43
44
45
Effect of Rotary Blower and/or Reduced Throttle on Becker Blowcount at Denver Test Site
Constant Combustion Rating Curves for Full and Reduced Throttle Conditions at Denver Test Site
Effect of Energy Reduction on the Becker Blowcount - Bounce Chamber Pressure Relationship for Denver Test Site (Depth Interval = 11-16 feet)
Effect of Energy Reduction on the Becker Blowcount - Bounce Chamber Pressure Relationship for Denver Test Site (Depth Interval = 19-26 feet)
Effect of Energy Reduction on the Becker Blowcount - Bounce Chamber Pressure Relationship for Denver Test Site (Depth Interval = 27-33 feet)
Effect of Energy Reduction on the Becker Blowcount - Bounce Chamber Pressure Relationship for Denver Test Site (Depth Interval = 34-38 feet)
Effect of Energy Reduction on the Becker, Blowcount - Bounce Chamber Pressure Relationship for Denver Test Site (Depth Interval = 39-43 feet)
Effect of Energy Reduction on the Becker Blowcount - Bounce Chamber Pressure Relationship for Denver Test Site (Depth Interval = 44-50 feet)
Effect of Rotary Blower and/or Reduced Throttle on Becker Blowcount at Mackay Test Site
Constant Combustion Rating Curves for Full and Reduced Throttle Conditions at Mackay Test Site
Effect of Energy Reduction on the Becker Blowcount - Bounce Chamber Pressure Relationship for Hackay Test Site (Depth Interval = 5-10 feet)
Effect of Energy Reduction on the Becker Blowcount - Bounce Chamber Pressure Relationship for Mackay Test Site (Depth Interval = 11-15 feet)
Effect of Energy Reduction on the Becker Blowcount - Bounce Chamber Pressure Relationship for Mackay Test Site (Depth Interval = 16-20 feet)
46 Effect of Blower Elimination and/or Reduced Throttle on Becker Blowcount at Salinas Test Site
vi
Page No.
58
60
61
62
63
64
65
66
67
69
70
71
72
73
Fig. No.
47
48
49
50
51
52
53
54
55
Effect of Energy Reduction on the Becker Blowcount-Bounce Chamber Pressure Relationship for Salinas Test Site (Depth Interval = 29-34 feet)
Effect of Energy Reduction on the Becker Blowcount -Bounce Chamber Pressure Relationship for Salinas Test Site (Depth Interval = 48-52 feet)
Effect of Energy Reduction on the Becker Blowcount-Bounce Chamber Pressure Relationship for Salinas Test Site (Depth Interval = 65-69 feet)
Effect of Energy Reduction on the Becker Blowcount -Bounce Chamber Pressure Relationship for Salinas Test Site (Depth Interval = 73-77 feet)
Effect of Energy Reduction on the Becker Blowcount-Bounce Chamber Pressure Relationship for Salinas Test Site (Depth Interval = 95-99 feet)
Idealized Force Time-History Experienced in a Long Casing (from Rempe and Davisson, 1977)
Comparison of Actual Blowcount Increases with Predictions Based on Ratios of Impact Kinetic Energy for Salinas Test Site (Depth Interval = 29-34 feet)
Uncorrected Full Throttle Combustion Rating Curves for Salinas, Denver, and Mackay Test Sites
Estimated Kinetic Energy of Ram at Anvil Impact
56 Full Throttle Combustion Rating Curves for Salinas, Denver, and Mackay Test Sites Corrected to Sea Level Atmospheric Pressure
57 Idealization of How Diesel Hammer Combustion Efficiency Affects Becker Blowcounts
58
59
60
Paths of Becker Blowcount Increases for Decreasing Hammer Energy Based on Field Data and Ratios of Impact Kinetic Energy
Correction Curves Adopted to Correct Becker Blowcounts to Constant Combustion Curve Adopted for Calibration
Examples Illustrating the Use of Correction Curves to Correct Becker Blowcounts
vii
Page No.
74
75
76
77
78
80
84
86
89
90
92
94
95
97
Fig. No.
61
62
63
64
65
66
67
A.l
A.2
Photograph Illustrating the More Complicated Mast of the AP-lOOO Drill Rig (left) Compared to that of the B-lSO Drill Rig (right)
Comparisons of Uncorrected Becker Blowcounts Obtained with Different Drill Rigs at the Denver Test Site
Effect of Drill Rig on Corrected Becker Blowcount
Photograph Showing the Hydraulic and Cable Support System for the Diesel Hammer on the AP-lOOO Drill Rig Mast
Effect of Bit Diameter on Corrected Becker Blowcount
Uncorrected Becker Blowcounts from Initial and Redriving Test at Mackay Test Site
Correlation Between Corrected Becker and SPT Blowcounts
Pressure-Volume Relationship Used for Deriving Potential Energy Stored in Bounce Chamber
Example Calculation of Potential Energy of Diesel Pile Hammer Ram
viii
Page No.
99
100
102
103
105
lOS
115
120
124
Table No.
1
2
3
4
5
6
7
LIST OF TABLES
Existing Correlations Between Becker and SPT B1owcounts
Surronary of Becker Soundings Performed for Developing Becker-SPT Correlation
Potential and Impact Kinetic Energies for Sea Level
Potential and Impact Kinetic Energies for E1ev. 6000'
Influences of Procedures and Equipment on Becker B1owcounts
Recommended Procedure for Obtaining Becker Blowcounts
Summary of Data Used to Develop Corrected Becker-SPT B1owcount Correlation
ix
Page No.
18
23
82
87
111
112
114
/.
Determination of Penetration Resistance for Coarse-Grained Soils
Using the Becker Hammer Drill
by
Leslie F. Harder, Jr. and H. Bolton Seed
Chapter 1
INTRODUCTION
There are many cases in engineering practice where it is necessary to
determine the engineering characteristics of gravelly and coarse-grained
soils. Desirably this would be done in-situ, S1nce the properties of cohe
sionless soils are known to be influenced significantly by sample disturbance.
However, standard methods of in-situ soil exploration developed for sands,
such as the standard penetration test (SPT), the cone penetration test (CPT),
the self-boring pressuremeter, etc. give erroneous results in gravels because
the soil particles are large compared to the dimensions of the test equipment.
Furthermore, determining soil properties by laboratory testing is hampered by
the fact that it 1S virtually impossible to take undisturbed samples of
gravelly soils, except by in-situ freezing techniques, and these are
enormously expensive.
In consequence, the engineering properties of gravels are more custom
arily determined by constructing test pits to extract samples for grain size
distribution tests and for determining the in-situ density or relative density
of the gravelly soil. Representative samples are then prepared in the labora
tory to the same density or relative density as that of the field deposits and
used to determine engineering properties such as strength, deformation, and
compressibility characteristics. Alternatively, the engineering properties of
the deposit are assessed on the basis of judgment, based on a knowledge of the
2
grain-size distribution and the density of the deposit. Only occasionally has
in-situ testing been attempted or used for engineering property determinations
of gravelly soils.
In many cases the above procedures have provided useful data for design
studies. However, care must be exercised to insure that all relevant factors
influencing the interpretation of the test data obtained from the reconsti
tuted samples are considered in the final evaluation of properties. This in
volves consideration of changes in density, if it is necessary to change the
gradation by scalping or adopting a parallel gradation curve for preparation
of laboratory test specimens, and in some cases, consideration of other
effects such as "ageing," which is likely to change the properties of any
cohesionless soil over a long period of time.
In recent years it has been found necessary to explore other properties
of gravelly deposits, ~n addition to the conventional determinations of
strength, deformation and compressibility characteristics. These include the
response of gravelly deposits to cyclic loading, which may be induced by
earthquake shaking or wave action. It is only recently that the need for such
studies and determinations has been recognized. Some years ago it was the
conventional wisdom of the geotechnical engineering profession, for example,
that gravelly soils were not susceptible to large increases in pore water
pressure, leading possibly to liquefaction, under the effects of earthquake
shaking. It was generally believed that gravelly soils, because of their high
permeability, would be able to dissipate pore pressures virtually as fast as
they could be generated by earthquake shaking, and thus were not vulnerable to
liquefaction during earthquakes. Clearly this depends on the nature of the
soil (sandy gravels for example, may not be significantly more pervious than
sands); pore pressure dissipation also depends on the boundary drainage
3
conditions since a gravel is not free-draining if it is underlain and overlain
by relatively impervious layers of other soils.
The concept that gravels were not vulnerable to liquefaction was also
fostered by the better field performance of foundations on gravel, as compared
with sands, in earthquakes such as the Alaska earthquake of 1964, and by
laboratory tests, conducted under cyclic loading conditions, which showed that
significantly higher stresses were required, even under undrained cyclic
loading conditions, to induce high pore water pressures in gravelly soils than
in sands. It has since been recognized that the higher laboratory strengths
were due mainly to the effects of membrane compliance, and that when
laboratory test results are corrected for this effect, the cyclic loading
resistance of gravels is not very different from that for sands.
Finally and more importantly, there have been a number of cases in
recent years where liquefaction of gravelly deposits has been observed to
occur, with associated detrimental effects, during earthquakes. These events
have prompted a review of earlier earthquake performance of gravelly soils and·
several cases of earthquake-induced liquefaction in gravelly soils are now
recognized to have occurred.
Important cases of earthquake-induced liquefaction 1n gravelly soils
include:
(1) The liquefaction of a gravelly-sand alluvial fan deposit 1n the
1948 Fukui earthquake (Ishihara, 1985).
(2) The flow slide at Valdez in an alluvial fan containing large zones
of gravelly sand and sandy gravel in the 1964 Alaska earthquake
(Coulter and Migliaccio, 1966).
(3) The slide in the upstream gravelly-sand shell of Shimen Dam 1n the
1975 Haicheng earthquake (Wang, 1984).
and
(4) The slide 1n the upstream sandy gravel slope protection layer of
Baihe Dam 1n the 1974 Tangshan earthquake (Wang, 1984).
(5) The liquefaction of gravelly soils 1n level ground at the
Pence Ranch, and 1n sloping ground causing the Whiskey
Springs Slide, both during the 1984 Mount Borah earthquake
(Youd et al., 1985; Andrus et al., 1986).
4
In a number of these cases, the generation of soil "blows" at the ground
surface showed that particles up to 1 inch size had been carried upward by
flowing water, or that sand was washed out of sandy gravel deposits to form
sand boils at the surface.
Recognition of these effects has. led to a renewed interest 1n the
liquefaction characteristics of gravelly soils and in methods of field
exploration which can lead to meaningful determinations of their in-situ
characteristics. Since the nature of gravelly soils is likely to involve many
of the same problems in geotechnical investigations as sands, i.e. significant
variability within relatively short distances and significant changes in
properties due to sample disturbance, it has seemed desirable to explore the
possibility of exploring the properties of gravelly soils using procedures
which have proved successful for sandy soils; that is by the use of some type
of penetration test which can be performed rapidly, at a number of locations
Ln a deposit, to provide a representative index of overall characteristics.
Clearly such a test would need to be much larger in scale than the relatively
small-scale 8PT or CPT tests used widely for investigating the liquefaction
resistance and other properties of sands. In fact, a large scale version of
either of these tests would seem to provide a useful basis for investigating
the characteristics of gravelly soils. An added advantage of such an approach
is that a large-scale version of, say, the 8PT test should be just as
5
applicable in sands as the conventional SPT test and thus it should be
possible to correlate the results of the test results with the extensive body
of field performance data, such as liquefaction resistance and compres
sibility, through the development of correlations between the different test
procedures. This would provide a direct basis for evaluating the field
behavior of gravelly soils.
Fortunately such a large-scale type of penetration test already exists
~n the form of the Becker Penetration Test, developed in Canada in the later
1950's and now widely used for exploring the characteristics of deposits
containing gravel and cobble-size particles. The test has also been used by
several investigators for evaluating the penetration resistance of gravelly
soils. This report, therefore, presents a review of previous attempts, and
the results of an extensive new investigation conducted to develop a corre
lation between the results of the Becker Penetration Test and the Standard
Penetration Test. The object of the study was to provide a meaningful corre
lation between the results of these different test procedures and thus facil
itate the use of test data and experience already available for sands for
evaluating the probable behavior of gravelly and other coarse-grained
deposits.
6
Chapter 2
HISTORY OF THE BECKER PENETRATION TEST
The Becker Hammer Drill, shown in Figure 1, was developed by Becker
Drills Ltd. in Alberta, Canada during the late 1950's as a method for rapidly
penetrating deposits of gravels and cobbles. The method consists of driving a
double-walled casing into the ground with a double-acting diesel pile hammer.
During driving, air is forced down the annulus of the casing system to the
drive bit. Soil particles entering the bit are then transported up the inner
casing to the surface by the air flow and they are then collected in a cyclone
as illustrated in Figure 2. The principal applications of the device Ln
recent years have included gold-assaying of gravels~ installation of
piezometers in difficult soil conditions (e.g. Tarbela Dam foundation), and
the characterization of coarse-particle deposits.
Equipment
The diesel hammer used on Becker drill rigs is an International
Construction Equipment (ICE) Model 180; the hammer is rated at a maximum
energy of 8100 foot-pounds per blow. This type of pile hammer is closed off
at the top and part of its energy during driving is developed by the
compression of air in the top of the hammer cylinder during the travel of the
ram during each cycle. By measuring the pressure of this trapped air pressure
(bounce chamber pressure), an estimate of the driving energy can be obtained
for each blow. Correlations between potential hammer energy and bounce
chamber pressure have been developed by the manufacturer and these will be
discussed in a later section of this report.
The diesel hammer frame is mounted on rollers or wear blocks which move
along guides on the drill rig mast. Delivering 92 blows per minute, it is not
7 ,\
\
FIG. 1 PHOTOGRAPH OF BECKER HAMMER DRILL RIG
8
DIESEL HAMMER
AIR COMPRESSOR
-.
" " " • II " " • j) " • • • • , " II (J
" , " " " " " " • " .. • " " ,
0 " " " " " " II 0
" • II " " " 0 " ()
(J .. 11
" , 0
• • , 0 0
• " " • " ,
" " " 0 " • , , r1 ,
" • " " " , , 0 " ,
til ,. .. " 0 " til
" .. • .. 0 II " " " " • • .. til
" " " ,
" II " til • " fJ " .. .. " " "
II
" " .. • " " " " ,
" # " " 0 II " D
(J 0 • • " .. " 0 II " ()
, "
.. " " 0 " " '" " '" • 0 " .. " • 0 Q " . • a '" 0
" " " D " II p "
FIG. 2 SCHEMATIC DIAGRAM OF BECKER SAMPLING OPERATION
9
unusual for the hammer to achieve penetration r?tes of about 100 feet an hour. :'
On completion of each sounding, the casing is gripped with tapered slips and
raised by hydraulic grips. It usually requires about 40 minutes to withdraw
100 feet of casing from the ground.
The double-walled casing is composed of two heavy pipes arranged
concentrically (see Figure 3). The inner pipe floats inside the outer pipe,
separation being provided by neoprene cushions, and only the outer pipe
absorbs the direct impact of the hammer. The casing ~s provided in 8 to 10-
foot lengths, and segments are connected with threaded joints ~n the outer
pipe. An "0" ring seal ~s used on one end of each inner pipe segment to avoid
leaks between the outer and inner pipes. Casing pipes are available 1n three
sizes as follows:
S.S-inch 0.0. x 3.3-inch I.D. (Original size)
6.6-inch D.D. x 4.3-inch I.D.
9.0-inch 0.0. x 6.0-inch I.D.
Drill bits have two basic shapes: crowd-in bits and crowd-out bits. A
crowd-in bit is used to recover as much soil material as possible. A crowd-
out bit is used when driving might be difficult and/or when soil recovery is
not as important. Figure 4 shows photographs of some of the more commonly
used drill bits. A comparison of the 6.6 inch-D.D. Becker crowd-out bit and
the 2.0-inch O.D. SPT sampling shoe 1S shown 1n Figure S.
Becker Penetration Test
The Becker Penetration Test consists basically of counting the number of
hammer blows required to drive the casing one foot into the ground. By
counting blows for each foot of penetration, a more or less continuous record
of penetration resistance can be obtained for an entire soil profile. This
test was originally called the "Becker Denseness Test" and was developed in
AIR IN ..
HAMMER IMPACT
AIR DISCHARGE WITH SAMPLED MATERIAL
10
FIG. 3 REVERSE CIRCULATION PROCESS USED WITH BECKER HAMMER DRILL AND OPEN DRILL BITS (adapted from Becker Drills, Inc. 1 iterature)
A. 6.6-inch 0.0. Open 8-tooth Crowd-out Bit
B. 5.5 inch 0.0. Closed 8-tooth Crowd-out Bit
C. 7.3-inch 0.0. Open Felcon Crowd-in Bit (Used with 6.6-inch 0.0. Casing)
O. 5.5-inch 0.0. Open 3-web Crowd-in Bit
FIG. 4 TYPICAL DRILL BITS USED WITH BECKER HAMMER DRILL RIGS
11
Reproduced from best available copy.
FIG. S PHOTOGRAPH COMPARING 2-INCH 0.0. SPT SAMPLING SHOE WITH 6 SIB-INCH 0.0. CROWD-OUT BECKER DRILL BIT
12
13
Canada by using a plugged 8-tooth crowd-out bit with 5.5-inch O.D. casing.
The plugged bit was employed because it was found that open-bit soundings in
saturated sands often gave erratic results. Over the years, however, Becker
penetration testing has employed both open and plugged bits together with both
5.5-inch and 6.6-inch O.D. casing sizes.
On a number of investigations the Becker Penetration Test has often been
used for the purpose of obtaining equivalent Standard Penetration Test (SPT)
blowcounts and using correlations between SPT resistance and field behavior to
predict performance. During the last 13 years, several correlations between
Becker blowcounts and Standard Penetration Test (SPT) blowcounts have been
developed. Figures 6 through 9 present four correlations between Becker and
SPT blowcounts developed by different investigators, and Table 1 summarizes
some of the information pertinent to each correlation. In Figure 10 all four
correlations are presented together on the same plot. In &eneral there is
much scatter in the test data and there are wide variations in the proposed
correlations. Thus, for example, a Becker blowcount of 30 might be considered
to be equivalent to a SPT blowcount ranging between 30 and 80, depending on
which correlation is used.
The great variability of Becker-SPT correlations is due in large measure
to the fact that the different studies often employed different Becker and SPT
procedures and equipment, as well as different methods of data interpretation.
In addition, the studies involved the following deficiencies:
1. Ex~ept for the studies performed by Geotechnical Consultants, Inc.,
no attempt was made to monitor and correct for variations in energy
developed by the diesel hammer used for conducting the Becker
Penetration Test.
'0 o -..... II' 3 o
14
140~---------------------------------------------------,
120
CANADIAN DATA FROM BECKER DRILLS, INC FILES 5.5 - INCH O. D. CLOSED .BECKER BITS
o VULCAN WAY, RICHMOND, ac. (R. A. SPENCE LTD.)
o LYNN CREEK, N. VANCOUVER, B.C.
o HUNTER CREEK, NEAR HOPE, B.C.
t:::. NORTH VANCOUVER, B.C.(R.A. SPENCE LTD., 1973)
\l POWELL RIVER, B. C. (RIPLEY, KLOHN, 8 LEONOFF LTD., 1973)
• NEW WESTMINISTER, B.C. (RIPLEY, KLOHN, 8 LEONOFF LTD., 1973)
• MINORU BLVD., RICHMOND, B.C.
• STEVESTON HIGHWAY, RICHMOND, B.C.(R.M.HARDY 8 ASSOC. LTD., 1975) IOO~--------~---------+----------r---------~--------~
o
o o
80~--------~---------+----------r---------~--------~
~ 60~--------~---------+----------.~~------~--------~ ~ Z ::> o u 3
o o
BEST AVERAGE RELATIONSHIP BASED ON JUDGEMENT
g 0 ~ 40r---------~--------~~~~~--~--------~--------~ ~ Cl. V1
o • '\70
20~~~~~~~~-----+--------~~--------4---------~
• o
°0~-------4~20~--------4·0--------~6~0--------~80---------1~00
BECKER BLOWCOUNT, Na (blows/foot)
FIG. 6 CORRELATION BETWEEN BECKER AND SPT BLOWCOUNTS DEVELOPED FROM CANADIAN DATA OBTAINED FROM BECKER DRILLS, INC. FILES
-'0 0 -...... III ~ 0 j5
~ Z ~ 0 U ~ 0 ...J en ~ Q. en
140~------~()~--~----~r+~~~--r---------b
, 0 o
120~--------+----r&+--~~-------+--------~
()
100
()
80
0 60
40
()
20 6 5/8" o. D. OPEN BECKER BIT
SGC GRAVELS
D~o = 10- 30mm
SALT RIVER VALLEY, ARIZONA
00 20 40 60 80 BECKER BLOWCOUNT, NB (blows/foot)
FIG. 7 CORRELATION BETWEEN BECKER AND SPT BLOW COUNTS DEVELOPED BY SERGENT, HAUSKINS & BECKWITH (1973)
15
16
120~--------~----~--~---------r--------~---------'
• 100~--------+---------4-------~~---------+--------~
ao~-------+------.. --~-+~~o~-+---.----~--~~--~
o •
I
Z 60~-------."--~--~~---------r---------+---------; g / ~ / g .0.0· OJ /
e: 0 / ~ 40~--~·----+--+ __ ----~------~~--------~--------~
6 5/8" O. D. OPEN BECKER BIT
• BECKER BLOWCOUNTS ADJUSTED TO REPRESENT 8000 ft.-Ibs. OF ENERGY
o DATA FROM GRAVEL ALLUVIUM BENEATH SANTA FELICIA DAM FOUNDATION.
20 I--------J'-I-+------~- - - LEAST SQUARES FIT FOR DATA.
DATA FROM SAND AND GRAVEL STREAM • CHANNEL DEPOSITS AT SITE FOR
PROPOSED VERN FREEMAN DIVERSION STRUCTURE.
---- LEAST SQUARES FIT FOR DATA.
°O~~~---~-------~----------------------------~ W ~ ~ ~ 100 ADJUSTED BECKER BLOWCOUNT, NBA (blows/foot)
FIG. 8 CORRELATIONS BETHEEN BECKER AND SPT BLOWCOUNTS DEVELOPED BY GEOTECHNICAL CONSULTANTS. INC. (1981. 1983)
0 0 -...... til ~ 0 D I-z ;:) 0 u 3 0 ....J CD
I-a. V'l
140~------------------------------~----~~--~---------,
120
DATA OBTAINED FROM STUDY BY JONES • AND CHRI STENSEN (1982) OF GRAVEL
DEPOSITS IN POCATELL0..1IDAHO USING 65/8 INCH 0.0. OPEN BtoCKER BITS.
- BEST FIT LINE FOR POCATELLO DATA.
DATA OBTAINED BY NORTHERN 0000 ENGINEERING AND TESTING,INC., IN
GRAVELS, SANDS, SILTS AND CLAYS USING 5.5 INCH O. D. OPEN BECKER BITS. (JOB NO'S. 68-16,68-17,68-19,68-204)
100~---------r----------~---------+----------+-~-------1
80
0
• 0 • 60
• 40
0 0 0
~ 0 o 0
20 0
• 0
20 40 60 80 100 BECKER BLOWCOUNT, NB (blows/foot)
FIG. 9 CORRELATION BETWEEN BECKER AND SPT BLOWCOUNTS DEVELOPED BY JONES AND CHRISTENSEN (1982)
17
TABL
E 1:
E
xist
ing
Co
rrel
ati
on
s B
etw
een
BECK
ER a
nd S
PT
Blo
wco
unts
CORR
ELA
TIO
N SO
IL
TYPE
CQ
SING
D
RILL
8I
T
0.0
. Un
. }
CONF
IGU
RATI
ON
1 .
CANA
DIA
N DA
TA
FROM
BE
CKER
D
RIL
LS,
INC
. FI
LES
A.
Vul
can
way
, R
ichm
ond,
bC
(R
. A.
Sp
ence
L
td.)
S
ilty
& C
laye
y S
ilts
B.
Ly
nn
Cre
ek,
N.
Van
couv
er,
BC
Gra
vell
y Sa
nds
C.
Hun
ter
Cre
ek,
Nea
r H
ope,
BC
Sa
nds
& G
rave
ls
D.
Nor
th
Van
couv
er,
Be
(R.
A.
Spen
ce
Ltd
.)
Gra
vell
y &
S
ilty
San
ds
E.
Pow
ell
Riv
er,
BC
(Rip
ley,
K
1ohn
, &
Leo
noff
Ltd
.)
Gra
vell
y Sa
nds
F.
New
Wes
tmin
ster
, BC
(R
iple
y,
K1o
hn,
& L
eon
off
Ltd
.)
Sand
s &
Sil
ts
G.
Min
oru
Blv
d.,
R
ichm
ond,
B
e Sa
nds
H.
Ste
vest
on
HW
y.,
Ric
hmon
d,
Be
(R.M
. H
ardy
&
Ass
oc,
Ltd
.) S
ands
&
Sil
ts
2.
Sarg
ent,
H
ausk
ins
& B
eck w
i th
(1
97
3)
(Sa
lt
Riv
er
Va
lley
, A
rizo
na)
3.
Geo
tech
nica
l C
on
sult
an
ts,
Inc.
(1
981,
1
98
3)
A.
Sant
a F
elic
ia
Dam
Fou
ndat
ion,
C
ali
forn
ia
B.
Ver
n F
reem
an
Div
ersi
on S
tru
ctu
re,
Ca
lifo
rnia
4.
Jone
s an
d C
hri
sten
sen
(1
98
2)
Gra
vels
(0
50=
10
-30
mm
)
Gra
vels
(0
50=
4-
10 m
m)
Sand
s an
d G
ra v
e1s
5.5
5
.5
5.5
5
.5
5.5
5
.5
5.5
5
.5
6.6
6.6
6
.6
A.
Gre
at
wes
tern
Mal
ting
F
aci
lity
, P
oca
tell
o,
10
S
ilts
and
Gra
vels
6
.6
B.
Nor
ther
n E
ngin
eeri
ng &
T
esti
ng
, In
c.
Fil
es
(Job
N
os.
68
-16
, 6
8-1
7,6
8-1
9,
68
-20
4)
Sand
s,
Gra
vel
s,
Bak
ed S
hale
5
.5
Clo
sed
Clo
sed
Clo
sed
Clo
sed
Clo
sed
Clo
sed
Clo
sed
Clo
sed
Ope
n
Ope
n *
Ope
n *
Ope
n O
pen
NOTE
: *
Den
otes
th
at
Geo
tech
nica
l C
on
sult
an
ts,
Inc.
m
easu
red
boun
ce
cham
ber
pre
ssu
res
and
used
the
th
e IC
E en
ergy
ca
lib
rati
on
ch
art
s to
ad
just
mea
sure
d B
ecke
r b1
owco
unts
to
re
pre
sen
t va
lues
co
nsi
sten
t w
ith
an
8000
ft
-lD
. en
ergy
level.
f-
-' 0
0
- -0 0 ..- ......
en ~
0 .0
Z
t- o.
(/)
~I
~
/ I
/1
60
40
20
20
/ /
/ /
/ I
Fli
/:1
.~-----~-----+--
... ---
.
/
/ /
//
// /
/
/ /
/ /
/ /
/ /
/
40
6
0
CA
NA
DIA
N
DA
TA F
RO
M
BE
CK
ER
DR
illS
, IN
C. F
ilE
S
!I 1
/2· O
. D.
plu
gg
ed
BE
CK
ER
bit
.
SE
RG
EN
T,
HA
US
KIN
S
110
BE
CK
WIT
H 1
19
13
) 6
!I/8
· O
. D.
IIp
en
B
EC
KE
R
bll
.
/O!l
W7
l//1
0,
GE
OT
EC
HN
ICA
L C
ON
SU
lTA
NT
S,I
NC
.1i9
BI,
19
83
) 6
&/8
"0.0
. II
po
n
BE
CK
ER
b
il.
B.c
k.,
bll
lwC
llun
ta
adJu
aled
'0
' en
.rg
y I
lIvII
I
--
--
--
--
JON
ES
III
C
HR
IST
EN
SE
N 1
19
B2
) 6
&/8
"0.D
. o
pe
n
BE
CK
ER
b
it.
BO
1
00
1
20
BE
CK
ER
B
LOW
CO
UN
T,
NB
(b
low
s/fo
ot)
FIG
. 10
PR
EVIO
US C
ORRE
LATI
ONS
BETW
EEN
BECK
ER B
LOW
COUN
T AN
D SP
T BL
OWCO
UNT
14
0
t-'
'>£
)
20
2. No attempt was made to account for variations in equipment and
procedures used to perform the SPT. Many of these studies employed
the Becker "free-fall" SPT hammer and/or non-standard SPT samplers
to perform the SPT tests.
3. Many of the correlations employed Becker soundings with open-bits
and air recirculation to conduct the Becker Penetration Test. This
could have led to erratic and erroneous results due to the loosening
and removal of soil ahead of the bit. In some of the correlations,
the SPT was performed through open-bit Becker casing thus com
pounding the problem.
4. Most of the correlations were performed 1n soils having relatively
large gravel and cobble particles. SPT values in soils having such
large particles leads to highly questionable results, with judgment
indicating that the resulting SPT values would be too high to be
used with correlations developed for sand and silty sand deposits.
Never-the-less the studies do indicate that the penetration resistance
measured by the Becker Drill procedure has the potential for development as an
index of soil penetrability and that if tests were performed under suitably
standardized conditions, a useful correlation between SPT and Becker test
blowcounts could be developed. Accordingly a new investigation has been
conducted with the objective of providing such a correlation.
Chapter 3
FIELD STUDIES OF VARIABLES AFFECTING THE RESULTS OF BECKER PENETRATION TESTS
General
The principal purpose of the field investigations described in this
21
chapter was to obtain a better correlation between Becker blowcounts and SPT
blowcounts. Previous correlations were generally performed in gravelly soils
where the particle sizes were too large for the SPT to give a meaningful
result. Therefore, to develop an improved correlation, Becker and SPT tests
were performed in sands and silts at three different sites:
Salinas, California
Thermal ito , California
San Diego, California
Because of variations in SPT hammer energies and sampler configurations,
the SPT blowcounts obtained at these sites were corrected to equivalent N60
blowcounts using the procedures outlined by Seed et al. (1985). The N60 blow-
count represents a SPT blowcount obtained in a test where the hammer energy
delivered into the drill rods is equal to 60 percent of the theoretical free-
fall energy of a 140 Ib hammer falling 30 inches. It is also representative
of a blowcount obtained with a 2-inch 0.0. split spoon sampler having a cons-
tant I.D. of 1-3/8 inches (i.e. if space for liners is provided in the sampler
barrel, then liners are used).
Since the Becker drill rig ~s a relatively unfamiliar device to many and
has not been extensively investigated, it was also necessary to determine the
influence of different test parameters on the Becker blowcounts. The par-
ameters studied included bit diameter, bit type (open or closed), drill-rig
type, diesel hammer energy, and casing friction. Some of these parameters
22
were studied at the three sites listed above while other studies were per
formed at sand and gravel sites in Denver, Colorado and ~n Mackay, Idaho. A
summary of the field explorations is presented in Table 2.
Test Sites
The three sand/silt sites chosen to develop the Becker/SPT correlation
were picked because the sites already had good quality SPT tests performed ~n
relatively limited areas and because the soils appeared to have relatively
high uniformity (i.e. about the same blowcount) over a significant horizontal
distance. The Denver and the Mackay sites were chosen to investigate the in
fluence of several test parameters partly because the rig was already ~n those
areas at the time and because the soils at the two sites were also thought to
be relatively uniform ~n horizontal extent.
Salinas Test Site, California
The Salinas test site is located on the southern bank of the Salinas
River near Highway 68 (Figure 11). The site has been used extensively as a
testing ground for research on field exploration tools and techniques.
Research groups have included the United States Geologic Survey (USGS),
University of California-Berkeley (UCB) , and the Earth Resources Technology
Corporation (ERTEC). According to the ERTEC (1981) investigations (Reference
6), silt and sand exists in the upper 35 feet at this site. These deposits
are believed to have been deposited by the Salinas River and are of Holocene
age. Below about 35 feet the sediments consist of interbedded sands, silts,
and clays.
In addition to several cone penetrometer soundings, ERTRC drilled 8 SPT
boreholes at the Salinas site. These SPT tests were generally carried out in
the silt and sand within the upper 35 feet and provided an excellent
Tab
le
2:
Sum
mar
y o
f B
ecke
r So
undi
ngs
Per
form
ed F
or
Dev
elop
ing
Bec
ker-
SPT
Co
rrel
ati
on
SITE
D
ate
Dri
ll
Rig
So
undi
ng
Type
1111
9/84
A
P-1
000
(110
57)
6.6
-in
. op
en
CO b
it,
full
th
rott
le
1111
9/84
AP
-lOO
O
(110
57)
6.6
-in
. cl
ose
d
CO b
it,
full
th
rott
le
SAU
NA
S,
CA
**
8/2
8-2
9/8
5
AP-lO
OO
(1
1057
) 6
.6-i
n.
clo
sed
CO
bit
, fu
ll
thro
ttle
8
/29
/85
A
P-1
00U
(1
1057
) 6
.6-i
n.
clo
sed
CO
bit
, re
d.
thro
ttle
THER
MAL
ITO
CA
**
11
/21
/84
AP
-lOO
O
(110
57)
6.6
-in
. op
en
CO b
it,
full
th
rott
le
, 11
1211
84
AP-lO
OO
(1
1057
) 6
.6-i
n.
clo
sed
CO
bit
, fu
ll
thro
ttle
SAN
DIE
GO,
CA
**
4
/18
/85
8-
180
(110
11 )
6
.6-i
n.
open
CO
bit
, fu
ll
thro
ttle
4
/18
/85
B
-180
(1
1011
)
6.6
-in
. cl
ose
d
CO b
it,
full
th
rott
le
6/1
J/8
5
AP
-100
0 (1
1057
) 6
. 6-i
n.
clo
sed
CO
bit
, fu
ll
thro
ttle
6
/1J/
85
B
-180
(1
1055
)
6.6
-in
. cl
ose
d
CO b
it,
full
th
rott
le
6/1
4/8
5
AP
-100
0 (1
1057
) 5
.5-i
n.
clo
sed
CO
bit
, fu
ll
thro
ttle
61
14/8
5 AP
-lOO
O
(110
57)
5. 5
-in
. op
en
CO b
it,
full
th
rott
le
6/1
4/8
5
AP
-100
0 (1
1057
) 5
. 5-i
n.
open
C
I b
it,
full
th
rott
le
DEN
VER,
CO
6
/27
-28
/85
AP
-lOO
O
(110
57)
6.6
-in
. cl
ose
d
CO b
it,
full
th
rott
le
6128
/85
AP-lO
OO
(1
1057
) 6
. 6-i
n.
clo
sed
CO
bit
, re
d.
thro
ttle
6
/28
/85
A
P-1
000
(110
57)
6.6
-in
. op
en
CO b
it,
full
th
rott
le
6/2
8/8
5
AP
-100
0 (1
1057
) 7
.J-i
n.
open
C
I b
it,
full
th
rott
le
8/21
184
AP-lO
OO
(1
1057
) 6
.6-i
n.
open
CO
b
it,
full
th
rott
le
8/21
184
AP-lO
OO
(1
1057
) 6
. 6-i
n.
clo
sed
CO
b
it,
full
th
rott
le
fvlAC
KAY,
10
71
17/8
5 AP
-lOO
O
(110
57)
7. J
-in
. op
en
C1
bit
, fu
ll
thro
ttle
71
17/8
5 A
P-1
000
(110
57)
6.6
-in
. op
en
CO b
it,
full
th
rott
le
7117
/85
AP-lO
OO
(1
1057
) 6
.6-i
n.
clo
sed
CO
bit
, fu
ll
thro
ttle
71
17-1
8/85
AP
-lOO
O
(110
57)
6.6
-in
. cl
ose
d
CO b
it,
red
. th
rott
le
NOTE
S:
* D
enot
es
no
boun
ce
pre
ssu
re r
eadi
ngs
take
n **
D
enot
es
a sa
nd
/sil
t si
te w
here
SP
T bl
owco
unts
w
ere
ava
ila
ble
CO
D
enot
es
a cr
owd-
out
bit
C1
D
enot
es
a cr
owd-
in b
it
Max
. D
epth
J9 ft
. J8
ft
.
99
ft
. 9
9 ft
.
29 ft
. 29
ft
.
52
ft
. 5
2 ft
.
55
ft
. 5
5 ft
. 5
5 ft
. 5
5 ft
. 5
5 ft
.
55
ft
. 5
5 ft
. 4
9 ft
. 49
ft
.
4J
ft.
45
ft
.
J9 ft
. J8
ft
. J7
ft
. J8
ft
.
Num
ber
2*
2
*
J 4 2 2 2 2 2 2 2 2 2 5 2 1 2 I 1 1 2 2 J
I I
N
W
r-________________ .-______________________________________ ~24
SALINAS TEST SITE p .. POWER UNE POLES
• o
• • o
[RT[C PILCON HA"WER SPT BOREHOLES
[RTEC OO~UT HAW"ER 5PT BOREHOLES
BECKER SOUNDINGS
AP-IOOO DRIL.L RIG
6 YB-inch O. O. CASING
198. FULL THROTTLE PUl66ED II-TOOTH CROWD-OUT BIT
19115 Fl.U. THROTTLE PLU66ED I-TOOTH CROWD-OUT BIT
IMS II£DUCED THROTTLE PUlGGED I-TOOTH CROWD-OUT BIT
p ..
BCC-C •
p .. Bce-F
o
BCC-G
o
BCC-H
o
1 N
T-. • • BCC-E
ace-I o
IICC-O •
0 20 4() feet I I I
T-2 • 5-1
5-5 0
T-8 •
ace-A • 5-1 o
IIQC-A
o
S-5 o
Bce-B !IOC-B • 0
HILLTOWN ROAD
NOTE: POSITION OF ErnEC BOREHOLES ONLT APPtIOII'WATEU' U)CATED RELATIVE TO BECMER SOUNDINGS
a
T-6 •
FIG. 11 GENERAL LAYOUT OF BORINGS AND SOUNDINGS AT SALINAS TEST SITE
25
opportunity to calibrate the Becker apparatus. For four of the ERTEC bore
holes, the SPT tests were carried out with a Pilcon trip hammer, a hammer type
which has been found to give reasonably consistent energy levels near 60
percent of the theoretical free-fall value (Liang, 1983; Decker et al., 1984;
and ERTEC, 1984). The other four boreholes employed a non-standard donut
hammer with a rope and cathead release. In general, the non-standard donut
hammer gave much higher SPT blowcounts than did the Pilcon trip hammer. Since
the energy characteristics of the second hammer system were unknown, only the
SPT blowcounts obtained with the trip hammer were used ~n this investigation.
All ERTEC borings at this site employed a SPT split-spoon sampler with room
for liners, but with no liners used. As discussed by Seed et al., (1985), the
effect of removing the liners ~s thought to decrease the blowcount by about 10
percent for blowcounts around 10 and about 30 percent for blowcounts around 35
or more. Since most of the Salinas blowcounts were less than 20, to correct
the ERTEC blowcounts to equivalent N60 values, a correction factor for energy
level of 1.00 and a correction factor for sampler geometry averaging about
1.15 were used.
The initial explorations at this site with the Becker Penetration Test
were carried out in November 1984 and consisted of two Becker Open Casing
(BOC) soundings and two Becker Closed Casing (BeC) soundings. The gradation
curves for the samples obtained in the BOC explorations are shown in Figure
12. Although these initial soundings were performed with the diesel hammer at
full throttle, the bounce chamber pressure gage was not available at the time
and, therefore, the actual bounce pressures were not determined. Since subse
quent studies revealed that the bounce chamber pressure was a very important
parameter, 7 additional BCe soundings with measurements of bounce pressures
were made in August 1985. Four of these later Bec soundings were conducted
t- I C!)
w
3:
>- (D
a:::: w
z 1L..
I- Z w
u a:::: w
0...
100
90
80
10
60
50
40
3D
20
10 o 0.0
01
GRA
DA
TIO
N
CURV
E H
YD
RO
MET
ER
AN
AL
YSI
S S
IEV
E A
NA
LY
SIS
------
~
-20
0
-10
0
-60
d
O
-16
-S
_4
3
1S
-3
/4-
31
2-
3-
6-
12
-
SA
LIN
AS
TE
S
SIT
E
1984
BE
CK
ER
B
OC
S
AM
PLE
S
DE
PT
HS
=O -
17
fe
et
DE
PT
HS
= 1
4 -
36
fe
et
0.0
1
0.1
1
.0
10
.0
10
0.0
GR
AIN
S
IZE
IN
M
ILL
IME
TE
RS
CLRY
OR
SI
LT
FI
NE
S I
~!".
~ I
GRR
VEL
F
INE
I
MED
IUM
I C
OA
RSE
FIN
E
I CO
AR
SE I C
OB
BLE
S
FIG
. 12
GR
ADAT
ION
CURV
ES
FOR
BECK
ER S
AMPL
ES O
BTAI
NED
AT T
HE
SALI
NAS
TEST
SIT
E N
0
\
27
with reduced throttle settings ~n order to study the effect of reduced energy
on the Becker blowcount.
Thermalito Test Site
The Thermalito test site is located at Thermalito Afterbay Dam, near
Oroville, California. This site is located near the downs'tream toe of the
embankment at Station 104. The foundation at this site consists of fluvial
deposits formed during the Pleistocene. The California Department of Water
Resources had previously drilled a number of SPT boreholes at this site
(Reference 3). There were 9 boreholes at this site which employed a safety
hammer and 4 which employed a donut hammer for performing the SPT tests. For
calibration purposes, it was decided to use only the results from the 9 safety
hammer tests. Velocity measurements indicated that the SPT hammers had
velocities just prior to anvil impact that were equivalent to a kinetic energy
equal to 70 percent of the theoretical free-fall value. Since safety hammers·
are generally able to transmit between 90 to 95 percent of the kinetic energy
through the anvil, a rod energy equivalent to 63 percent of the theoretical
free-fall value was used to interpret the results of these tests. Thus, the
Thermalito SPT blowcounts required a correction factor of 1.05 for energy
level. As no liners were used in the SPT sampling tubes and the blowcounts
were between 20 and 40, a correction factor of 1.2 to 1.3 for sampler con
figuration was also employed to correct the blowcounts to equivalent N60 blow
counts.
Becker explorations were performed at Station 104 in November 1984. Two
Becker open-casing (BOC) soundings and two Becker closed-casing (BCC) sound
ings were performed in the vicinity of the previous SPT borings (Figure 13).
The soil of interest at this site is a 20-foot thick layer of fine to medium
sand lying beneath an 8-foot thick cap of compact silt. Figure 14 presents
DO
WN
STR
EA
M
EM
BA
NK
ME
NT
TO
E 7
o 10
2
0 f
••
t I
I 1
J K
H
M
• 0
0 0
r'--.J
F
L
79-1
04
A
B
D
I •
• 0
• •
• •
E
C
• •
• B
AR
BE
D W
IRE
FE
NC
E
------1
&
III
• 1&
__
--II
J(
•
AC
CE
SS
R
OA
D
a • •
BC
C-A
<:>
B
OC
-A
• <:>
ac
e-B
BO
C-B
• 19
79
SA
FE
TY
H
AM
ME
R
SP
T
BO
RE
HO
LE
o 19
81
DO
NU
T H
AM
ME
R
SP
T
BO
RE
HO
LE
• 19
81
SA
FE
TY
HA
MM
ER
S
PT
B
OR
EH
OLE
• 19
81
PIS
TO
N/P
ITC
HE
R
SA
MP
LIN
G B
OR
E
BO
RE
HO
LE
19
84
BE
CK
ER
SO
UN
DIN
GS
A
P-I
OO
O D
RIL
L R
IG
6 5
/8-i
nch
O. D
. C
AS
ING
• P
LUG
GE
D
a-T
OO
TH
C
RO
WD
-O
UT
BIT
<:>
OP
EN
a
-TO
OT
H
CR
OW
D-O
UT
B
IT
FIG
. 13
. GE
NERA
L LA
YOUT
OF
BORI
NGS
AND
SOUN
DING
S AT
THE
RMAL
ITO
TEST
SIT
E N
0
0
I- :I:
D w
::x
>- II)
~
w
z l.L..
I-
Z w
u ~
w
a...
GRA
DA
TIO
N
CURV
E --------
-
HYDR
OMET
ER
AN
ALY
SIS
SIEV
E A
NA
LYSI
S
100
-IS
_8
-4
3
/8-
3/4
-3
/2-
3-
S-
12-
90
TH
ER
MA
l/T
O T
ES
T' S
ITE
1
98
4
BE
CK
ER
B
0 C
SA
MP
LE
S
80
DE
PT
HS
= 8
-2
9 f
ee
t 70
60
50
40
30
20
101
' A
5P
y/
01
"'"
'"
''
III 1
11
1
II 1
'1'"
II
"!I
'"'
0.0
01
.-
._
-._
--
GRA
IN
SIl
E
SA
ND
CL
AY
OR
SIL
T
FIN
ES
FIN
E M
EDIU
M
FIN
E G
CO
BBLE
S
FIG
. 14
GR
ADAT
ION
CURV
ES
FOR
BECK
ER S
AMPL
ES O
BTAI
NED
AT T
HE
THER
MAL
ITO
TEST
SIT
E N
1.
0
gradation curves for samples obtained from the sand layer by the Becker BOC
sampling operations.
San Diego Test Site
30
The San Diego test site is located on North Island Naval Air Station in
a parking lot immediately south of Building 652, (Figure 15). According to a
study by ERTEC (1981) the site is ~n an area where artificial fill was placed
across a channel ~n 1945 in order to link North and Coronado Islands. Both
the fill and the underlying near-surface deposits consist chiefly of sands and
silty sands. Gradation tests performed by ERTEC (Reference 6) indicated that
these sands generally had between 7 and 24 percent finer than the No. 200
s~eve (0.074 mm) and roughly 2 to 4 percent clay fines (finer than 0.002 rom).
As with the Salinas site, ERTEC had made extensive use of the site to
perform field studies and had made 4 SPT boreholes using the Pilcon trip
hammer and 4 SPT boreholes using the non-standard donut hammer/rope-and
cathead system. As for the Salinas site, only the trip hammer blowcounts were
used in the current study to develop a correlation with Becker blowcounts (see
section on Salinas Test Site, California). As described for the Salinas site,
to correct the measured results to equivalent N60 blowcounts, no correction
factor for SPT hammer energy was required. However, because the SPT blow
counts at the San Diego site ranged from very small to very large values, the
correction factors required to allow for the omission of liners from the
sampling tube ranged from 1.00 to 1.35.
In April 1985, two BOC and two BCC soundings were carried out. Unlike
the explorations at Salinas and Thermalito which used an AP-I000 Becker drill
rig, the soundings at San Diego used a B-180 Becker drill rig.
SAN DIEGO TEST SITE NORTH ISLAND N.A.S.
PARKING LOT SOUTH OF BUILDING 652
Cl ERTEC DONUT HAMMER SPT BOREHOLE
.... 1.-...-
j '''K'' I _ .. _.= ..... ~.=
, NAVAl. SUPPLY c~
.";:--•• r,::.r:~ t.?"
FIG. 15 GENERAL LAYOUT OF BORINGS AND SOUNDINGS AT SAN DIEGO TEST SITE
31
32
Denver Test Site
The Denver test site 1S located on the northeast edge of town in a sand
and gravel pit owned by the Colorado Sand and Gravel Company. The deposits
tested consisted of a partially cemented gravelly sand in the upper 42 feet.
Figure 16 shows a photograph of this material exposed in an adjacent cut.
Below 42 feet, the material changed to a sandy clay which became more sandy
between 52 and 55 feet.
Becker soundings were made in the period June 13-14, 1985 and again on
June 27-28, 1985. The purpose of these soundings was to investigate the
effects of var10US test parameters on the resulting Becker blowcounts. The
parameters studied at this site included bit diameter, open-bit vs. closed
bit, drill rig type, and diesel hammer throttle setting. In all, 13 plugged
bit and 7 open-bit soundings were performed. Figure 17 shows the general
layout of the soundings.
Three of the closed-bit soundings performed using the June 27/28 test
period (BCC-5, BCC-7, and BCC-9) were not used in determining the effects of
test parameters. Because the location of the first group of soundings was
only approximately known, sounding BCC-5 was apparently located over or near a
previous sounding. This was believed to be the case because the blowcounts
from this sounding were low and inconsistent with other soundings performed 1n
the same manner. Therefore, the blowcounts from this sounding were not used.
The results of soundings BCC-7 and BCC-9 were not used because a special
bypass valve had been installed in the hydraulic system supporting the hammer
to the mast and had been open at the time these tests were made. When open,
this valve was intended to allow the hydraulic fluid to flow faster and enable
the hammer to keep up with the descending casing. If successful, this would
have increased hammer efficiency, and the blowcount would have decreased.
33
> ~ ,.:' ',,' If '.. ',,:: '" .' .... ' ",., '"
~~;"'-~~~~\!!~"""-,, ~,_~o'~v' . ....." '.,.- ~~..i.f' _~""...--,.:.::::;~~
a) Denver Test Site
b) Gravelly Sand Exposed in Adjacent Cut
FIG. 16 PHOTOGRAPHS ILLUSTRATING DENVER TEST SITE AND MATERIALS
o BOC-2
BOC-I 0
BCC-II • o BOC-]
0 BCC-7
a BOC-O
BCC-8 •
• BCC-6
BCC-5 • • BCC-B
BOC-A 0
BCC-A •
DRILL RIG
• AP-IOOO
0 AP-IOOO
• AP-IOOO
0 AP-IOOO
0 AP-IOOO
BCC-9 0
• BCC-IO
BOC-C 0
OBOC-B
BCC-] 0
• BCC-2
\ee' --'\ 20 • r BCC-I
0 BCC-4
DRILL RIG
0 B-180
• AP-IOOO
• AP-IOOO
0 AP-IOOO
0 AP-IOOO
GROUP B
THROTTLE SETTING DRIU BIT
FULL THROTTLE " ~/8-h.cb O. O. Cl..OSED 8LOwER ON I-TOOTH CROWD-OUT
FULL THROTTU: .......... ) " ~a -1.eII D.O. a..oSED BLOWER ON '1ALY'I I-TOOTH CROWD-OUT 0".
REDUCED THROTTLE BLOWER OFF
FULL THROTTLE a ~.-Iach D.D. OPEN BLOwER ON I-TOOTH CROWD-OUT
FULL THROTTLE T !l4-lnch 0.0. OPEN BLOWER ON FELCON CROWD-IN
IB-foot DEEP CUT --.,.--
GROUP A
THROTTLE SETTING DRILL BIT
FULL THROTTLE " ~a-I.c" D. D. CLOSED BLOWE II 0lIl a-TOOTH CROWO-OUT
FULL THROTTLE 6 ~a-Iac" 0. D. CLOSED BLOWER ON I-TOOTH CROWD-OUT
FULL THROTTLE ~-'-I.c .. 0.0. CLOSED BLOWER ON I-TOOTH CROWD-OUT
FULL THROTTLE ~.5 -iacil D.o. OPEN BLOWER ON a-TOOTH CROWD-OUT
FULL THROTTLE ~.5-I .. c .. 0. D. OPEN BLOWER ON 3-WEB CROWD-IN
FIG. 17 GENERAL LAYOUT OF BECKER SOUNDINGS AT DENVER TEST SITE
34
35
Although the new valve failed to make any significant difference, it was
decided for consistency not to use the results from these two soundings.
Mackay Dam Test Site
The Mackay test site is located between Stations 7 and 9 on the crest of
Mackay Dam. Mackay Dam is located 1n central Idaho and was built between 1909
and 1917. The principal method of construction consisted of dumping sandy
gravel in roughly 25-foot thick lifts. The explorations at this test site
were performed in conjunction with the studies of the performance of Mackay
Dam during the 1983 Mount Borah Earthquake (M =7.3). The soundings performed s
in this test area were made to investigate the effect of driving an open-bit
vs. a closed-bit, and to study the effect of hammer energy on Becker
blowcount. Figure 18 shows a plan view of the arrangement of soundings 1n the
test area. Details of the history of the dam, materials, performance during
the earthquake, and other explorations are presented elsewhere (Harder, 1986).
Effect of Closed vs. Open-Bits on Becker Blowcount
Becker Drills, Inc. literature and staff recommend using a closed-bit to
obtain reliable Becker blowcounts. Previous studies conducted 1n gravelly
sands 1n Canada have indicated that a closed-bit gives blowcounts roughly
twice the values obtained with an open-bit. The correlations provided by the
company literature and file (Figure 6) are based on. soundings performed with
5.S-inch closed crowd-out drill bits. However, samples cannot be obtained
using a closed-bit. Thus, rather than perform and pay for two soundings at
each drilling location, most firms and agencies have opted to use mainly open-
bit soundings. By this means, both samples and blowcounts are obtained from
the same sounding. However the use of open-bit soundings often leads to
overly conservative and unreliable blowcounts.
MA
CK
AY
R
ES
ER
VO
IR
• yo
, ',.
. .,
. lU
ll III''''
o c I
MA
CK
AY
T
ES
T
SIT
E
AP
-1
00
0 D
RIL
L R
IG
6 5
/8-l
nch
O. D
. CA
SI N
G
OP
EN
I-
TO
OT
H C
RO
wD
-OU
T B
IT
fUL
L T
HR
OT
TL
E
a B
LO
WE
R O
N
OP
EN
7
.'-l
ncll
o.D
. fE
LC
ON
C
RO
WD
-IN
BIT
-fU
LL
T
HR
OT
TL
E
a B
LOW
ER
ON
C
LO
SED
I-
TO
OT
H C
RO
WD
-OII
T
BIT
fU
LL
TH
RO
TT
LE
a
BL
Ow
ER
O
N
CL
OU
D I
-TO
OT
H C
RO
WD
-OU
T B
IT
RE
DU
CE
D
TH
RO
TT
LE
a
BL
owE
R
Off
C
LO
UD
I-T
OO
TH
CR
OW
D-O
UT
liT
R
ED
UC
ED
T
HR
OT
TL
E
a B
LO
WE
R
ON
ICC
-I
10
C-1
•
0 IO
C-8
1
0C
-.
ICC
-II
BO
C-I
O
BC
C-I
B
CI;
;-7
CO
.
0 •
• -.
I ..
, .. ,
l.-
• •
BC
C-.
B
CC
-8
I~
-.0"
';
II ~.':'.:::It.IIJ..'ll,::,'''~U:r .• ,.
''o.1
III1
1 I'"
u 1._
" I ...
......
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JI,
,_'I
I'
CI.
II
....
. I
U' •• "
.'11
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1M
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1
1111
JI
.VI
1111
1.
AD
D
1
0 ,
...
, II
•
FIG
. 18
GE
NERA
L LA
YOUT
OF
BECK
ER S
OUND
INGS
AT
MACK
AY T
EST
SITE
l..J
(j\
37
Figure 19 presents uncorrected blowcounts from two 6.6-inch, closed,
crowd-out bit soundings performed at the San Diego test site. Also shown in
this figure are uncorrected SPT blowcounts performed in the same general area
by ERTEC (1981). This figure shows excellent agreement in both the trend and
general magnitude of the blowcounts from both types of penetrometers. How
ever, as shown in Figure 20, Becker blowcounts from two open crowd-out bit
soundings performed in the same area do not compare well with the blowcounts
from the closed-bit soundings. Although reasonable agreement is obtained
between the two sets of Becker data in the upper 30 feet, the blowcounts from
the open-bit soundings drop to much lower values than those for the closed-bit
soundings below this depth. For one open-bit sounding, BOC-A, the blowcounts
actually drop to zero at depths where the closed-bit soundings and the SPT
blowcounts indicated a dense soil. The open-bit soundings are clearly too low
below the 30-foot depth.
The experience of open-bit soundings g1v1ng erroneously low blowcounts
was also repeated for the fine sands at the Salinas and Thermalito test sites.
Figure 21 shows that one of the BOC soundings at Salinas developed unreason
ably low blowcounts between a depth interval of 25 to 35 feet. Figure 22
shows that both BOC soundings at Thermalito gave unreasonably low blowcounts
between a depth interval of 20 to 29 feet.
The fact that open-bit soundings g1ve erroneously low values in sands
can be attributed to the recirculation process drawing up excessive amounts of
sand into the casing and out of the hole. This creates a loosening and
removal of sand ahead of the bit and leads to a relatively low blowcount. The
loosening and removal is further encouraged below the water table where the
water tends to flow up, under relatively high gradients, into the bottom of
the casing. The situation is analogous to performing SPT tests in a borehole
°1 10
2
0
30
4
0
50
6
0
70
8
0
90
I
')
i I
I
I -.
8-1
80
BE
CK
ER
D
RIL
L R
IG
I SP-
'\J
--
BC
C-A
e
.6 -
Inch
PLU
GG
ED
CR
OW
D-O
UT
BIT
SM
--
BC
C-B
6
.6 -
Inch
P
LUG
GE
D C
RO
WD
-OU
T B
IT
10
L
~
-ER
TE
C
SP
T
TIB
, t_
• E
RT
EC
S
PT
T
2B
• E
RT
EC
S
PT
T
3B
• E
RT
EC
S
PT
T
4A
I .c
--~
-----
-.....
. 2
0
~ -GI G
I ..- ~
30
:x:
~
0..
W
0
--<
--
I SM
• • ~-.
-4
0 l-
• ..;
::::::
-~~
<....
• ---
---•
::c~ _
__
__
__
• -~
50
'"
· --
•
60
' I
I I
, I
I ,
I I
o 10
2
0
3b
4
0
50
6
0
70
BO
9
0
UN
CO
RR
EC
TED
P
EN
ET
RA
TIO
N
RE
SIS
TA
NC
E (
blo
ws/f
oo
l)
FIG
. 19
UN
CORR
ECTE
D BL
OWCO
UNTS
FR
OM S
PT A
ND C
LOSE
D BI
T BE
CKER
PEN
ETRA
TION
TES
TS P
ERFO
RMED
AT
THE
SA
N DI
EGO
TEST
SIT
E w
0
0
-.CU ~
':t: l n.
W
o
O~
I?
'"
2~
3?
4?
5?
60
1
0
80
9
p
10
20
....
u --
----
----
--=
----
----
---
.....
.. ~"'
\L-.
..:~
B-1
80
B
EC
KE
R
DR
ILL
RIG
BC
C-A
6
.6 -
Inch
PW
GG
ED
C
RO
WD
-OU
T B
IT
BC
C -B
6
.6 -
Inch
PLU
GG
EO
CR
OW
D -
OU
T B
IT
••••
• '"
B
OC
-A
6.6
-In
ch
OP
EN
C
RO
WD
-OU
T B
IT
--
-B
OC
-B
6.6
-In
ch O
PE
N
CR
OW
O-O
UT
BIT
··4
{ ....
..... .:.:
. . .:.:.
.~.
~ ...
.:.."t .
. .....
.... "-
.; ...
.... .
, .
---~
~
----
----
----
--...
......
....
----
--
'---
--;::
.. -
~---
..... . '-
-==~
'. .-
-. ~:.
:..:
..~ ;':'~ -::c
::: -~~j;lI.
--.:-
:.'::
... 3
0 I-
'"
.~.-:-
..~ ...
...
.. , ..
\ .....
... <
.,
....
l
..... _-
"" ..
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---
...... -::
:.:: -...
'" ...
_o
J
40
--~ -
«.;.
.~
<..
..-
-... 5
0
--= -
----
-..;;: -
-.;;;
--
60
I •
I I
I "'
1 ,
I I
o 10
2
0
30
4
0
50
6
0
70
8
0
90
UN
CO
RR
EC
TED
P
EN
ET
RA
TIO
N
RE
SIS
TA
NC
E
(blo
ws/
foo
t)
sp
SM
\ SM \
FIG
. 20
CO
MPA
RISO
N OF
UNC
ORRE
CTED
BEC
KER
BLOW
COUN
TS
FROM
OPE
N AN
D CL
OSED
BIT
PEN
ETRA
TION
TE
STS
PERF
ORM
ED A
T TH
E SA
N DI
EGO
TEST
SIT
E W
I.
D
0 A
P-lO
OO
BEC
KER
Dri
ll R
ig
SPT
tes"
ts w
ith
Pllco
n H
<Nrm
er
&.6
-1n
. 0
.0.
Ca
sin
g
·1 •
10
f-::,
•• I
ML
• 0
• A
•
• 0
,. • •
• IS
M
~r D
EPTH
(ft
)
I
30
I-
0
40 I
50
0
• • •
--2
-•
=""
• •
• •
0 •
• •
• 0
• 0
0 0
• •
0 t
0 0
0 •
0 ,
• 0
• ••
•
• I
--BC
C-A
P
lug
ge
d C
row
d-o
ut
BIt
-BC
C-B
P
lug
ge
d C
row
d-o
ut
BIt
•
SPT
Bo
reh
ole
12
•
SP
T B
ore
ho
le
T4
0 BD
C-A
O
pen
Cro
wd
-ou
t B
It
• SP
T B
ore
ho
le
T6
0 B
DC
-B
4len
C
rciw
d-ou
t B
I t
• SP
T B
ore
ho
le
T8
10
20
JD
40
10
20
JO
LHCD
RREC
TED
E£C
KER
BL
DW
CO
ltolT
. H
I lH
:DR
RE
C1E
D S
PT
BLDW
COLW
T.
H
FIG
. 21
UN
CORR
ECTE
D BL
OWCO
UNTS
FR
OM S
PT A
ND B
ECKE
R PE
NETR
ATIO
N TE
STS
PERF
ORM
ED A
T TH
E SA
LINA
S TE
ST S
ITE
SP
-S
M
CH
~
a
Or-------~--------_r--------,_--------r_------_,--------_r--------,_--_,
~
10
o o
20
.-0
(I)
0 0
AP-IO
OO B
ECKE
R D
rIll
RIg
6.
6-In
. 0
.0.
Cas
Ing
o
SP
T te
sts
wit
h s
afe
ty H
amm
er
t •
• •••
• • .....
.... • •
J S
M-
SP
•••
(I)
DEPT
H (I
I
:..
(ft
J
00
0
0 •
Ql
Ql
• 0
0 ••
•••
• •
)0
• B
ore
ho
le
79-1
04
.. B
ore
ho
le B
lA-1
04
5P
T A
•
Bo
reh
ole
BlA
-10
4 S
PT
B
40
•
Bo
reh
ole
BlA
-10
4 S
PT
C
-B
CC
·A
Plu
gg
ed
Cro
wd-
out
Bit
•
Bo
reh
ole
BIA
-lD
4 S
PT
0
-BC
C-B
P
lug
ge
d C
row
d-ou
t B
it
• B
ore
ho
le B
IA-1
04
SP
T E
•
Bo
reh
ole
BlA
-l0
4 S
PT
F
0 BD
C-A
£pen
C
row
d-ou
t B
it
• B
ore
ho
le B
lA-1
04
SP
T G
0
BO
C-B
5D
'
Ope
n C
row
d-ou
t B
i t
• B
ore
ho
le B
lA-1
04
5P
T
J
D
20
4D
6D
8D
20
4D
6D
OC
mR
EC
TE
D
BEC
KER
B
LOW
CO
ll-lT
, N
s Lt
Cm
RE
CT
ED
5P
T BL
OW
CDI.J
oIT,
N
FIG
. 22
UN
CORR
ECTE
D BL
OW
COUN
TS .
FROM
SP
T AN
D BE
CKER
PE
NET
RAT
ION
TE
STS
PERF
ORM
ED
AT
THE
THER
MAL
ITO
TE
ST
SIT
E
.j::
.....
where neither water nor drilling mud has been used to stabilize the sand at
the bottom of a hole.
42
Confirmation that the recirculation process was loosening the sand below
the bit was achieved by performing a SPT test through the Becker casing at San
Diego. The depth chosen for this test was at approximately 7 feet, where the
ERTEC trip hammer tests indicated an uncorrected SPT blowcount of 10 (See
Figure 19). When the Becker drill bit reached a depth of 7.2 feet, the
recirculation process was stopped and the SPT split spoon sampler was inserted
down the inner casing. After placing the sampler into the casing, the bottom
of the split spoon reached a depth of 7.4 feet and sank another inch when the
Becker SPT hammer was attached to the sampling rod (i.e. before driving, the
bottom of the sampler was approximately 3 inches beyond the bottom of the
Becker bit). The resulting SPT blowcount was only 3, a value less than a
third of that predicted by the ERTEC results (Figure 23). This result
indicates that previous SPT-Becker blowcount correlations where SPT tests were
performed through the Becker casing may have utilized erroneous results.
The heave problem at the bottom of a hole is apparently not limited to
fine sand. Figures 24 and 25 compare uncorrected blowcounts from open and
closed-bit soundings performed at the Denver test site, where the soil LS a
gravelly sand down to about 42 feet with a sandy clay lying at lower depths.
Figure 24 compares blowcounts obtained with 6.6-inch 0.0. casing and bits and
Figure 25 compares blowcounts obtained with 5.5-inch 0.0. casing and bits. In
both figures, the open-bit soundings give consistently lower blowcounts than
do the closed-bit soundings.
The overall effects of bit diameter and configuration (open vs. closed)
are readily summarized ~y the data in Figure 26, which shows the blowcounts
measured in four of the Denver soundings. Each of the four soundings
--cu
43
UNCORRECTED SPT BLOWCOUNT (blows/foot) OO~ ______ ~5~ ______ ~I~O ________ ~1~5 ________ ~2~O ________ ~2~5 __ ~
5
SPT .PERFORMED THROUGH BECKER CASING
(f
e sz
SPSM
cu 10
X ~ Q.
l£J C
15
SM
ro~ ________ L-________ L-________ L-__ ~~ __ ~ __ L-__ ~
eA •• SPT TESTS PERFORMED AT SAN DIEGO TEST SITE BY ERTEC IN MUD-FILLED ROTARY BOREHOLES IB, 2B. 3B. a 4A
FIG. 23 COMPARISON OF SPT BLOWCOUNT PERFORMED THROUGH THE BECKER CASING WITH SPT BLOWCOUNTS PERFORMED IN MUD-FILLED ROTARY BOREHOLES
.. .. -o 10
20
-3
0
:J:
l- n.
w
Q
40
50
60
0
0
0 00
0
-!of
otlO
O ~.,
o 0
0 0
0 0 0 0 0
0 0
0 §
0 0
0 ~
08
0
00
0
o 0
00
0
DO
0
0 0
0 0
aJ
00
0
o 80
0 0
00
0
0 ~
0
m
:t.
oOi~
· 0
0
o 0
.. .
10
20
DE
NV
ER
T
ES
T
SIT
E
AP
-IO
OO
DR
ILL
RIG
6
~/8-inch
O.
D.
CA
SIN
G
Mfj
M
0
0 0
8 0
0 0
0 •
0 •
• 0
• t:
o~lO
0
• •
Mfj
. 9
o If
; ••
• .0
•
• •
• •
• • ••
• •
·Ie •
• •
• •
••
... •
• B
CC
-6
PLU
GG
ED
8
-To
oT
H C
RO
WD
-OU
T
BIT
• •
BC
C-B
P
LUG
GE
D a
-TO
OT
H C
RO
WD
-OU
T B
IT
• •
0 B
OC
-I
OP
EN
a
-TO
OT
H C
RO
WD
-OU
T B
IT
0 B
OC
-2
OP
EN
FE
LCO
N
CR
OW
D-I
N B
IT
0 B
OC
-3
OP
EN
F
ELC
ON
CR
OW
D-I
N B
IT
30
4
0
50
6
0
70
8
0
UN
CO
RR
EC
TE
D
BE
CK
ER
B
LOW
CO
UN
T,
N.
:~!t
12
6
14
2
In
114
sw-
GW
CL
90
10
5
1211
16
1 14
8
FIG
. 24
CO
MPA
RISO
N OF
UNC
ORRE
CTED
BEC
KER
BLOW
COUN
TS
FROM
6.6
-INC
H O
PEN
AND
CLOS
ED B
IT S
OUND
INGS
PE
RFOR
MED
AT
THE
DENV
ER T
EST
SITE
.j;>
~
O---
~~~~
~~~~
Dr--~-
----
=-'r
---~
--r-
----
----
------
----
----
----
I .1 (<
:>
• -At
'~"f3
0 &I;
0 '"
0'
, 0
o~ 0
• I
00
a
..• f3
.O~N.~
".". TES
T SI
TE
T
I o
." f3
•
--..
. _
.-I
•
'ii
~
10
20
J: 3
0
I- 0. ~ 4
0.-
50
.-
o ~8
r&
r-L
0
0 (C
) 9
o ,0
P"'0
reif
o 8-
~. ~
~8
EI
0'.
0~ ~"
• ~
o 0
0 9J
&0
••
00
o~
aoo
1 o
B ~C
S g
• ~.
0
0~0 M
•
o 0
' 0
0 ~o
3.
00 to
-
yg
I6EJ
0
~o
00
0
".~
f3 '
" f3
01
\'
" 0
' '
8£
J ~
• "
0 . ,
o ,8
0
::
0 0
o <f
i:I1#
0
OL
l0'
~
OJ
8 A
.~8
• 00
1
0 • ~.
• or
!- ee
O~
• OA
• •
I
• .I
. 1
•
.1 •
'\J
1 B
CC
-A P
LUG
GE
D a
-TO
OT
H C
RO
WD
-OU
T
BIT
B
CC
-B P
LUG
GE
D B
-TO
OT
H C
RO
WD
-OU
T B
IT
o B
OC
-A O
PE
N
B-T
OO
TH
C
RO
WD
-OU
T
BIT
o
BO
C-B
OP
EN
B
-TO
OT
H C
RO
WD
-OU
T
BIT
o B
OC
-C O
PE
N
3-W
EB
C
RO
WD
-IN
BIT
8
BO
C-D
OP
EN
3
-WE
B C
RO
WD
-IN
BIT
I I
I I
I I
I 6
00
10
20
30
4
0
50
6
0
70
8
0
UN
CO
RR
EC
TE
D
BE
CK
ER
BLO
WC
OU
NT,
NB
sw
GW
CL
FIG
. 25
CO
MPA
RISO
N OF
UNC
ORRE
CTED
BEC
KER
BLOW
COUN
TS
FROM
5.5
-INC
H O
PEN
AND
CLOS
ED B
IT
SOUN
DING
S PE
RFOR
MED
AT
THE
DENV
ER T
EST
SITE
-i
'lJ
l
Orl---------r---------r---------r---------r---------r---------r--------~--_,
10
20
J(J
DEPT
H (f
t J 40
50
DE
NV
ER
TE
ST
SIT
E
AP
-JO
OO
DrI
ll R
Ip
----
-.....
e--
e ,e
e------~
~
.... ;::
..
.:
-e~
e-- '. e_ -e
...-
=::
-,
0
~
o ~.
~o _
. ~
p---
o e
_
~~cf
~
0::
--e
-'0
-_
~.
--~~
,0.
,o~'.o
~, •
0
' •
b.
• --0
•
• ""0
...
... ;-.,
. ......
. 0 -.-
......
~
---*
-B
CC
-'
6.6
-1n
. 0
.0.
Plu
gg
ed
Cro
wd-
out
Bit
--
e--
BC
C-A
5
.5-1
n.
0.0
. P
lug
ge
d C
row
d-ou
t B
it
-O-8
0C
-1
6.6
-1n
. 0
.0.
Ope
n
SW
GW
CL
i---
---I
--0
--
BO
C-B
5
.5-1
n. O.D~
Ope
n C
row
d-ou
t B
it
Cro
wd
-cu
t B1
t 6D1~------~--------~--------~----------
______
______
______
______
__ _1
o ·2
0
40
60
80
10
0
12
0
14
0
lNC
ORR
ECTE
D
E£C
K£R
BL
OW
CO
LNT,
N
.
FIG
. 26
EF
FECT
OF
BIT
DIAM
ETER
AND
CON
FIGU
RATI
ON O
N BE
CKER
BLO
WCO
UNT
.j:-
(J
'\
0 0,
10
.. .. - :r
20
I- 0..
W
0
301
40
1
10
20
SO
4
0
50
6
0
70
80
9
0
,.
Ii i
_
, i
MA
CK
AY
T
ES
T
SIT
E
AP
-IO
OO
DR
ILL
RIG
6
5/B
-ln
ch 0
.0. C
AS
ING
F
UL
L T
HR
OT
TLE
-B
LOW
ER
ON
6 8
0C
-
8 7
0S
-In
c" 0
.0.
"[L
CO
N C
RO
WD
-IN
BIT
0
0 B
OC
-8
OP
EN
C
FlO
WD
-O
UT
BIT
<> B
OC
-1
0
OP
EN
C
FlO
WD
-OU
T
81T
(19
85
) 00
• ••
• B
CC
-5
PLU
GG
ED
C
RO
WD
-O
UT
BIT
0
0
0 I
• B
CC
-6
PLU
GG
ED
C
RO
WD
-O
UT
81T
0 •
• 0
BO
C -
I O
PE
N
CF
lOW
O-O
UT
B
IT
(19
84
) I
• B
CC
-I
PLU
GG
EO
C
RO
WD
-O
UT
81T
<> 40
8
• ••
• •
o f~6
• 1
00
• ~<>
C:£
0 •
.. 0
• I
6.
/,,\
0
~~.
I •
• •
0 6
°
.::>
0°
0 •
6 •
• 0
0 ~
6 6
• 6
0 I
I I
I I
I 10
2
0
30
4
0
50
8
0
70
8
0
UN
CO
RR
EC
TE
D
BE
CK
ER
BLOWCOUN~
N,
FIG
. 27
CO
MPA
RISO
N OF
UNC
ORRE
CTED
BEC
KER
BLOW
COUN
TS
FROM
6.6
-IN
CH
OPE
N AN
D CL
OSED
BIT
SO
UNDI
NGS
PERFOR~1ED
AT T
HE
MACK
AY T
EST
SITE
GW
.j::-
.
'-I
48
represents a different combination of bit s~ze and configuration. As expected
the closed s.s-inch bit gives a significantly lower blowcount than does the
closed 6.6-inch bit. However, a seemingly inconsistent result is indicated by
the fact that the larger 6.6-inch open-bit produced a significantly lower
blowcount than did the s.s-inch open-bit. At times, the blowcount from the
6.6-inch open-bit reached zero despite the fact that the plugged bit of the
same size gave blowcounts greater than 40 at the same depths. A possible
explanation why the larger open-bit gave lower blowcounts than the smaller
open-bit is the fact that the larger bit also has a larger inside diameter
(4.3 inches vs. 3.3 inches). The larger inside diameter may more easily
transmit the gravel particles which range up to about 2 to 3 inches in the
gravelly sand at this site. For the smaller inside diameter, the gravel
particles are more likely to block or partially block the bit opening, thus
making the open-bit act more like a plugged or closed-bit.
There is probably a critical grain size or gradation where the particles
are sufficiently large to plug or to arch across the bit opening caus~ng open
bit blowcounts to be essentially the same as closed-bit blowcounts. The
particle sizes required for adequate archlng or blocking are apparently at
least as large as those in a sandy gravel. This observation is based on the
fact that at Mackay Dam the open-bit and closed-bit soundings gave essentially
the same blowcounts (Figure 27). The soil at Mackay Dam is basically a silty,
sandy, gravel with approximately 65 percent of the grains retained on the No.
4 sieve (DsO = 6 - 20 rom) and maximum particle sizes up to about 3 to
6 inches. A similar result was found at Folsom Dam where open and closed-bit
soundings were carried out in the embankment shell and foundation. For the
soundings in the shell material having a gravel content of about 70 percent
(i.e. only about 30 percent passing the No.4 sieve), open and closed-bit
49
soundings gave about the same blowcounts after correcting for energy effects.
However, for the soundings in the gravelly sand foundation where the gravel
content was generally between only 10 and 60 percent, the open-bit soundings
were often significantly lower than the closed-bit soundings (Reference 10).
The results presented in this section clearly show that open-bit
soundings often give erroneously low blowcounts, particularly for saturated
sandy soils. Although gravels apparently have large enough particle sizes
that arching and plugging often causes open-bit soundings to have the same
penetration resistance as plugged bit soundings, it may not always be known if
sufficient gravel sizes exist to assure that representative blowcounts are
obtained. Therefore, it is recommended that only plugged bit soundings be
used to characterize soil deposits.
Effect of Diesel Hammer Energy on Becker Blowcount
Most engineers used to working with SPT tests believe that the energy
imparted to the sampling rods is more or less constant regardless of the
blowcount of the soil being investigated. For example, although there is some
variability with operator and testing conditions, it is now common to regard a
SPT safety hammer used with a rope and cathead release as generally giving
about 60 percent of its theoretical free-fall energy. This 60 percent energy
level is considered applicable regardless of whether the SPT blowcount is 2
or 50.
Constant energy conditions are not a feature of the double-acting diesel
hammers used in the Becker Penetration Test. One obvious reason for this is
that the energy is dependent upon combustion conditions; thus anything that
affects combustion, such as fuel quantity, fuel quality, air mixture and
pressure all have a significant effect on the energy produced. For example,
50
the operator of the Becker drill rig has control of a throttle that controls
the amount of fuel injected into the combustion chamber (see Figure 28). That
throttle can be adjusted to a variety of settings and the amount of combustion
energy can be varied significantly. The procedure is analogous to the use of
an accelerator in an automobile: the more fuel provided, the faster the
casing will move into the ground (i.e. the lower are the blowcounts).
Although the operator generally prefers to operate at as high a throttle
setting as possible in order to get the job done sooner, some operators use a
reduced throttle setting near.the surface or Ln soft zones.
The amount of kinetic energy delivered by the ram at impact depends on
the amount of combustion energy developed on the previous blow to drive the
ram back up the cylinder. As shown in Figure 29A, the interior of a double
acting diesel pile hammer is closed off at the top to allow a smaller stroke
and a faster driving rate. At the top, trapped air in the compression
cylinder and bounce chamber acts as a spring. The amount of potential energy
within the ram at the top of its stroke can be estimated by measuring the peak
pressure induced in the bounce chamber. Figure 30 shows a drawing of the
monitoring gauge used to measure the bounce chamber pressure. The higher the
bounce chamber pressure becomes, the higher LS the potential energy of the
ram. Also shown in Figure 29 is a correlation between potential energy and
bounce chamber pressure developed by ICE.
Another reason why the energy is not a constant with the Becker Hammer
Drill is that the energy developed is dependent on the blowcount of the soil
being penetrated. The dependency of hammer energy on blowcount can be
demonstrated by comparing Becker blowcounts to the bounce chamber pressures
measured during driving. Shown in Figure 31 is a situation where the hammer,
operating at a bounce pressure of 20 psi, produces a blowcount in the ground
:OO1r-~-_ 13
91~~~-14
1lI--+--15
16
2 --Fan Ic,,----,r:'\ 3-_"'I!r1'
6-~,-" ~!;:=O-T+-I-_
9-~~$~8 10---i~
11
Diesel Pile Hammer (1) Upper Cylinder (2) Lifting Pin
~3) Cam Surface 4) Lower Cylinder 5) Starting Fluid Injector
(6) Starting Device (7) Lifting Lever (8) Injector (9) Combustion Chamber (10) Anvil (11) Anvil Retainer (12) Lifting Eye
D mmJm
D
(13) Cylinder Head (14) Chamber Ports (15) Bounce Chamber (16) Fuel Tank (17) Ram
FIG. 28 ICE MODEL 180 DIESEL PILE HAMMER (adapted from ICE literature)
51
.. 6
ffi ~
ffi i :Ii ... z
~ ~ ~ ~ 2: ~ ii: 5 iii W •
:il .n § > N
is ~ 0
o ~ ... :! iii d a: j Q ...
i ~ ;:i !:! ~ ..
... ~ 5
Bounce Chamber
Top-Of-Slroke Port Closure Impacl,lQnilion Exhaust Top-Of - Stroke
A) IDEALIZED OPERATIONAL CYCLE OF DIESEL PILE HAMMER (MODIFIED FROM REMPE AND DAVISSON, 19771
is 0;
e:. 2' I
w a: ~
~ f 20 w 0 ~ «(
" ~ "
10
....
.... ~ ~
,
""""'" ....
0 I ... ~ .. I""" ........,
I . ... - """'"
.... ~ ~ I
6 7 a EQUIVALENT WH ENERGY - (FT .L.B;S. 1000)
GRAPHS VAUD QNLY IF HAMMER IS OPERATED VERTICAU Y AND WITH GAGE HOSE AS FUIIHISHED BY INTERNATIONAl. CONSTRUCTION EQUIPMENT. INC.
I r i
.J I
< i
~! Ii
Bl POTENTIAL ENERGY CALI BRATION FOR I. C. E. MODEL 180 DIESEL PILE HAMMER (FROM I. C. E. LITERATURE)
FIG. 29 OPERATIONAL AND POTENTIAL ENERGY CHARACTERISTICS OF DIESEL PILE HAMMER USED ON BECKER DRILL RIGS
52
8--.1i1
2---+
2---.11
~~ --4
~JiF;JJ---5 ~l/..---3
Output Energy Rating (1) Bounce Chamber (2) Hose
Instrument (Typical)
(3) Push Button (4) Gauge
(5) Graph (6) Adaptor (7) Socket (8) Plug
FIG. 30 MONITORING GAGE FOR BOUNCE CHAMBER PRESSURE (adapted from ICE 1 i terature)
53
54
1000~--~----~----~--~----~----~---'-----r----~---'
100
INCORRECT HYPOTHETICAL
CONSTANT ENERGY ~
• Z
~ z ::> 0 u ~ 0 ....I CD
a::: LU ::.::: U LU CD
10
18 28
FIG. 31 IDEALIZATION OF RELATIONSHIP BETWEEN BECKER BLOWCOUNT AND BOUNCE CHAMBER PRESSURE
55
of 30. According to the correlation presented in Figure 29B, for a 50 ft
length of pressure hose, a bounce pressure of 20 psig measured at sea level
corresponds to a potential energy of about 6800 ft.-lb. If the energy level
were constant, then the bounce pressure should stay at 20 psig regardless of
blowcount and would be represented by the vertical dotted line in Figure 31.
However, this does not occur because when the casing bit enters a softer
material, the blowcount goes down and the amount of casing displacement per
blow increases. With increasing casing displacement, a larger amount of
energy from the expanding combustion gases is directed into the soil leaving
less energy to send the ram up the cylinder for the next blow. With less
energy on the next stroke, the ram would not compress the air in the bounce
chamber to the same extent as on the previous stroke and the potential energy
for the next stroke is thus reduced. If the blowcount continues to drop, the
bounce chamber pressure and the potential energy of the ram continues to drop.
Conversely, if the blowcount increases, then there is less casing displacement
per blow and more of the combustion energy is directed upward in raising the
ram. With the ram travelling upward with more energy, the air in the bounce
chamber pressure compresses more and the potential energy for the following
stroke is increased. Thus, even for absolutely constant combustion conditions
(i.e. constant air-fuel mixtures) the potential energy of the ram does not
remain constant. Figure 31 indicates a typical relationship between Becker
blowcount and bounce chamber pressure (potential energy) for constant combus
tion conditions. The results shown in Figure 32 are actual blowcount and
bounce chamber data points from tests performing at the Salinas test site
under full throttle conditions in 1985. Although there is some scatter due to
the fact that the gauge reading is only accurate to about the nearest half psi
1000
• z .... -z ;:) o
~ CD
a: 1&1 lII: (.) 1&1 CD
10 4 6 I
..
IA -, r .. ·
j
'~ ~ ~Ai
I:0Il:
~
V
10 . 12 14 6 8 20
BOUNCE CHAMBER PRESSURE (psiQI
56
./ L
.- V" ~'" r I/J ~ JI!fl
~.
22 24 26 28
FIG. 32 RELATIONSHIP BETWEEN BECKER BLOWCOUNT AND BOUNCE CHAMBER PRESSURE FOR FULL THROTTLE COMBUSTION CONDITIONS AT THE SALINAS TEST SITE
and the fact that about 300 points are plotted, the data clearly shows the
trend discussed above.
Effect of Blower and/or Reduced Throttle
57
If the Becker Hammer Drill always operated with relatively constant
combustion, then all the blowcount and bounce chamber data should fall within
the scatter of the data points in Figure 32 and the blowcounts could be used
without further correction. Unfortunately, as mentioned previously, combus
tion conditions can and do vary significantly.
When the U.S. branch of Becker Drills changed from a 5.S-inch 0.0.
casing to a 6.6-inch 0.0. casing as a more or less standard procedure, their
operators found that it required.a higher blowcount to drive the casing. To
compensate for this, a rotary blower or supercharger was added to feed more
a~r into the combustion chamber. This blower is connected to the intake port
and it helps to clear the combustion chamber of exhaust gases. Better clear
ing in turn allows a higher throttle setting and more fuel to be used during
the combustion p~ocess than would otherwise be possible. With a higher com
bustion energy, U.S. Becker operators are able to keep blowcounts with the
larger 6.6-inch casing from getting uneconomically high. The Canadian Becker
Hammer rigs, which still predominantly employ the smaller casing, do not
generally use this blower.
To examine the effect of the blower, two 6.6-inch closed-bit soundings
were performed at the Denver test site with the blower turned on. In the same
area, two other 6.6-inch closed-bit soundings were performed with the blower
turned off together with a corresponding reduction ~n throttle setting.
Figure 33 shows the uncorrected Becker blowcounts for all four soundings
plotted against depth. As can be observed, the soundings with the blower
Or-~.r--~----~---r--~~--~--~----r---~--~~--~--~~~r----r--~~--~--~----r---~
~,8
D~NVER T
EST
SI
TE
A
P-IO
OO
D
RIL
L
RIG
%
:~~=:
BLO
WER
O
N
..
9]0
0
6 5
/8 lO
ch 0
.0.
PLU
GG
ED 8
-TO
OT
H
CR
OW
D-O
UT
B
IT
0 B
ee -
10
11
0
0 0
0 B
ee _
II
BLO
WE
R
OFF
..
• 0
0 I
• U
'1
10
...
II
••
• •
• ••
10
0
~1. •••
00
0
•• •
0 .s
.0
:;
••
0 d>
~~I
_ .
m ~
J:
I a..
w
o
00
o
O<:
JJ
C
o o
401
~.
W
o.
• I)
0
501
.. ~I
.I 0
0
0 -
00
0
00
•
60
1
I I
I I
I I
I I
I I
I I
0 10
2
0
30
4
0
50
60
7
0
80
9
0
100
110
120
UN
CO
RR
ECTE
D
BE
CK
ER
BLO
WC
OU
NT,
N.
0 0
I I
130
140
150
160
170
180
FIG
. 33
EF
FECT
OF
ROTA
RY B
LOW
ER A
ND/O
R RE
DUCE
D TH
ROTT
LE O
N BE
CKER
BLO
WCO
UNT
AT D
ENVE
R TE
ST S
ITE
CL
lJl
co
59
turned off p~oduced blowcounts roughly twice those ln soundings performed with
the blower turned on.
The change in blowcounts results from a change in combustion conditions.
Figure 34 compares the constant combustion rating curve data (blowcount vs.
bounce chamber pressure) from the two soundings which used the blower with the
data from the two soundings which did not use the blower. The two conditions
produce very different rating curves, with the "blower off" condition glvUlg a
rating curve to the left of the curve for the "blower on" condition. This is
consistent with the blower producing a lower blowcount (i.e. higher combustion
energy).
Figures 3S through 40 present most of the same data only grouped in 4-
to 6-foot depth increments. In general, a lowering of the bounce chamber
pressure by about 4 to 7 psi was enough to double the blowcounts. However,
this is inconsistent with the potential energy curves shown in Figure 29B.
According to this figure, a drop in pressure of 6 psi, say from 18 to 12 psig,
would produce only about a 26% reduction (4680 ft-lb./6310 ft-lb.) ln blow
count. Thus, although the changes in bounce chamber pressure were consistent
with the trend of the blowcount change, the potential energy charts supplied
by ICE (Figure 29B) were inadequate for predicting the magnitude of the effect
of potential energy on the blowcounts.
Similar studies were performed at the Mackay test site. Two 6.6-inch
closed-bit soundings performed with the blower on were compared to three
similar soundings performed with the blower off and/or with the throttle
reduced. Figure 41 shows the uncorrected blowcounts for all five soundings
plotted against depth. Again, the soundings with the blower turned off
produced blowcounts significantly higher than those in soundings performed
with either the blower turned on and/or with a reduced throttle setting.
,.,
C£NYER TEST SITE (E!eyatlon SJOD ft.)
Depth Interval = II - SS ft. .,. Blower-on and Full Throttle Combustion
O Blower-Dff and Reduced 0, Throttle Combustion
60
IO~~~2~~4---L-6~~~8~~IO~~1~2~~14~~16~~1~8---~2~O~~22~~2~4---~2~6---~2'e BOUNCE CHAMBER PRESSURE (pli91
FIG. 34 CONSTANT COMBUSTION RATING CURVES FOR FULL AND REDUCED THROTTLE CONDITIONS AT DENVER TEST SITE
1000
100
ID Z
.... -Z :l o
~ ..J CD
II: UJ :.:: u UJ CD
10
10 2 6
.., (I> .
CC ~I!t .. o<~ . . . . . . <~
. • 4 ~ . .~ •
DENVER TEST SITE (Elevation 5JOO ft.]
Depth Interval = 11 - 16 ft.
•• Blower-On and Full Throttle Combustion
Cl 0 BloJler-Off and Reduced Throttle Combustion
8 10 12 14 16 18 20 22 24 26
BOUNCE CHAMBER PRESSURE (psiql
FIG. 35 EFFECT OF ENERGY REDUCTION ON THE BECKER BLOWCOUNT - BOUNCE CHAMBER PRESSURE RELATIONSHIP FOR DENVER TEST SITE (Depth Interval = 11-16 feet)
61
I
I I
28
62
1000
0 I §II ~ "! 100 . .
A
~ . . III
Z - . L. . ... -• r-w:~ Z
~
A, ~ .. 0 u
~ oJ I%)
a: '" lII: U
'" I%)
10
CENVER TEST SITE (Elevation 5JDO ft.)
Depth Interval = 19 - 26 ft.
•• Blower-On and Full Throttle Combustion
00 BlOtler~ff and Reduced Throttle Combustion
10 2 4 6 e 10 12 14 16 18 20 22 24 26 28
BOUNCE CHAMBER PRESSURE (psi91
FIG. 36 EFFECT OF ENERGY REDUCTION ON THE BECKER BLOWCOUNT - BOUNCE CHAMBER PRESSURE RELATIONSHIP FORo DENVER TEST SITE (Depth Interval = 19-26 feet)
63
1000
I
100 ,ttL -I, . J<,
<~ . . . . .
.... j~ • .' 'A -...... . ,.
10
C£NVER TEST SIre (Elevation 5JOO ft.)
Depth Interval = 27 - JJ ft.
•• Blower-On and Full Throttle Combustion
00 Blower-Off· and Reduced Throttle Combustion
10 2 4 6 8 10 12 14 16 18 20 22 24 26 28
BOUNCE CHAMBER PRESSURE (psigl
FIG. 37 EFFECT OF ENERGY REDUCTION ON THE BECKER BLOWCOUNT - BOUNCE CHAMBER PRESSURE RELATIONSHIP FOR DENVER TEST SITE (Depth Interval = 27-33 feet)
1000
I
100
<:~_u n ·1e..
III Z ~-
v . . . Z ::l 0 . . . .,.. ~ .
<> t i l
U ~ 0 ~ CZI
II: I&J ~ U I&J CZI
10
C£NVER TES T SITE (Elevation 5JOO ft.)
Depth Interval = J4 - 38 ft.
•• Blower-On and Full Throttle Combustion
00 Blower-Off and Reduced Throttle Combustion
10 4 6 8 10 12 14 16 18 20 22 26
BOUNCE CHAMBER PRESSURE (psiQl
FIG. 38 EFFECT OF ENERGY REDUCTION ON THE BECKER BLOWCOUNT - BOUNCE CHAMBER PRESSURE RELATIONSHIP FOR DENVER TEST SITE (Depth Interval = 34-38 feet)
64
28
1000
I
100
v n
~ . nJ . . .
4' o'P . .
0 , . . (~ . 4 • . A~~
t 4,.
10
J
CEHVER TEST SITE (Elevation SJOO ft.)
Depth Interval = J9 - 4J ft.
•• Blower-On and Full Throttle Combustion
[J <> Blower-Off and Reduced Throttle Combustion
10 2 4 6 8 10 12 14 16 18 20 22 24 26
BOUNCE CHAMBER PRESSURE lpsi91
FIG. 39 EFFECT OF ENERGY REDUCTION ON THE BECKER BLOWCOUNT - BOUNCE CHAMBER PRESSURE RELATIONSHIP FOR DENVER TEST SITE (Depth Interval = 39-43 feet)
65
28
1000
100
~. I 0 I . . I . . • . . .
10 rw
C£NVER TEST SITE (Elevation 5JOO ft.)
Depth Interval = 44 - 50 ft.
.~ Blower-On and Full Throttle Combustion
cO Blower-Ofr and Reduced Throttle Combustion
10 2 4 6 8 10 12 14 16 18 20 22 24 26
BOUNCE CHAMBER PRESSURE (psigl
FIG. 40 EFFECT OF ENERGY REDUCTION ON THE BECKER BLOWCOUNT - BOUNCE CHAMBER PRESSURE RELATIONSHIP FOR DENVER TEST SITE (Depth Interval = 44-50 feet)
66
28
O.
101
~ - III II
I 2
0
J:
I- a..
w
0
30
1
40
1 0
".
. u
MA
CK
AY
T
ES
T
SIT
E
AP
-IO
OO
DR
ILL
R
IG
0
°0
0
65
/8-i
nch
O
. D
. P
LUG
GE
D
8-T
OO
TH
CR
OW
D-O
UT
BIT
0
• B
CC
-5
8°0
0
0
• B
CC
-6
BLO
WE
R
ON
0 B
CC
-7
BLO
WE
R
OFF
0
& B
CC
-8
.r
:roO
BC
C-9
B
LOW
ER
ON
B
UT
RE
DU
CE
D T
HR
OT
TLE
w
-0
0 6
0 6
0 6
0 6
0 0
0 6
°
° °
0 0 I
GW
6
0 6
0
° 0
.:::~O
0 <
) 0
()
181
<)
!:~
6 •
6 6
I I
I I
I I
10
20
3
0
40
5
0
60
7
0
80
UN
CO
RR
EC
TE
D
BE
CK
ER
BLO
WC
OU
NT
. N
B
FIG
. 41
EF
FECT
OF
ROTA
RY
BLOW
ER A
ND/O
R RE
DUCE
D TH
ROTT
LE
ON B
ECKE
R BL
OWCO
UNT
AT M
ACKA
Y TE
ST S
ITE
(J"\
'--J
68
Figure 42 presents the constant combustion rating curves for both conditions.
Figures 43 through 45 present the data for three depth intervals having the
least scatter. In a manner similar to that observed at Denver, a reduction ~n
bounce chamber pressure of only about 3 psi was sufficient to double the
b10wcount. Although the bounce pressures in these figures were generally less
than 10 psig and beyond the limits of the chart provided by ICE (Figure 29B),
the results are clearly inconsistent with the curves on the chart.
The most discouraging experience in attempting to use the ICE chart for
correcting b10wcount values occurred in relation to data obtained at the
Salinas test site. During the second series of explorations at this site ~n
August 1985, three 6.6-inch closed-bit soundings were performed with the
blower on and more or less full throttle. For four other 6.6-inch closed-bit
soundings, the operator was directed to reduce the throttle setting to obtain
vary~ng ~ounce chamber pressures. Figure 46 shows that the reduced throttle
settings greatly increased the Becker blowcounts above those obtained with
full throttle. The constant combustion rating curve obtained for the three
full-throttle soundings was previously presented in Figure 32. Figures 47
through 51 present data obtained with the reduced throttle settings for five
depth intervals. As may be observed, the results in these five figures trace
paths for increases in blowcount as a function of bounce chamber pressure
decreases (energy drops). These blowcount paths generally curve more sharply
upward after about an 8 psi drop. For example, Figure 47 shows the blowcounts
recorded in the depth interval of 29 to 34 feet. The three full-throttle
soundings produced average blowcounts of about 24 at a bounce chamber pressure
of roughly 20 psig. By operating the throttle so that the bounce chamber
pressure dropped to 10 psig, the b10wcounts increased to over 1000, an in
crease of about 4000 percent. By contrast, the ICE chart would indicate only
1000
100
ID Z ~-Z ::l o
~ oJ CD
a: 10.1 lII: <.J 10.1 CD
10
d (
~O c:J 1 0 ~ ,
:;. --
69
A
0 c:J
~
c:J
• : t:. "IB .. Q U' f). -
_[tI
l1I~ ~ • J~
~ ~ I 4 ~:..
t:.l ~tr I· ~, i> 1 ~ ( • I~ I ~t:. ... I'
~ Pr ~ 1
~ 1 " -- ...
7.A I ...... HIICKAY TEST SITE
(Elevation 6100 ft.)
Depth Interval = 5 - 37 ft.
• • Blower-On and Full Throttle Combustion
c:J 0 t:. Blower-Off and/or Reduced Throttle Combustion
'0 2 6 8 10 12 14 16 18 20 22 24
BOUNCE CHAMBER PRESSURE (psigl
FIG. 42 CONSTANT COMBUSTION RATING CURVES FOR FULL AND REDUCED THROTTLE CONDITIONS AT MACKAY TEST SITE
26 28
1000
CD Z
~-Z ~ 0 u ~ 0 ..J CZI
a:: L&J :II:: U L&J CZI
100
C
.[
(~O 10
u.;:::; .... ~ .... -""'S r.. - - H40CAY TEST SITE
(Elevation 6100 ft.)
Depth Interval = 5 - 10 ft.
• • Blower-On and Full Throttle Combustion
COt::. Blower-Off and/or Reduced Tihrottle Combustion
10 2 4 6 8 10 12 14 16 18 20 22 24 26
BOUNCE CHAMBER PRESSURE (psiql
FIG. 43 EFFECT OF ENERGY REDUCTION ON THE BECKER BLOWCOUNT - BOUNCE CHA~1BER PRESSURE RELATIONSHIP FOR MACKAY TEST SITE (Depth Interval = 5-10 feet)
70
28
1000
100
CD Z
.... -·z :l o
~ ..J III
a: I&J x U I&J III
10
1
71
1
,~
~
I~ I " c
I ~~ A -" I
I:lol..
HllClCAY TEST SITE (Elevation 6100 ft.)
Depth Interval = 11 - 15 ft.
• • Blower-Dn and Full Throttle Cambustion
C ¢ ~ Blower-Dff and/or Reduced Throttle Combustion
o 2 4 6 8 10 12 14 16 18 20 22 24 26 28
BOUNCE CHAMBER PRESSURE (psi9)
FIG. 44 EFFECT OF ENERGY REDUCTION ON THE BECKER BLOWCOUNT - BOUNCE' CHAMBER PRESSURE RELATIONSHIP FOR MACKAY TEST SITE (Depth Interval = 11-15 feet)
72
1000
I
l::..
I t:. I 100
...
c I jl'. ~ I ~f~~ i
0 "'-
<~ 1'1 l'l. .~ 10
I
""' I
HlICKAY TEST SITE (Elevation 6100 ft.)
Depth Interval = 16 - 20 ft.
• • Blower-On and Full Throttle Combustion
00 t:. Blower-Off and/or Reduced Throttle Combustion
'0 2 4 6 B 10 12 14 16 18 20 22 24 26 2B BOUNCE CHAMBER PRESSURE {psigl
FIG. 45 EFFECT OF ENERGY REDUCTION ON THE BECKER BLOWCOUNT - BOUNCE CHAMBER PRESSURE RELATIONSHIP FOR MACKAY TEST SITE (Depth Interval = 16-20 feet)
- - GI GI - - I ~ Q.
W
C
o •
~ ~I -U
II -o
v t·
ofll'
lI'§
10
J-
! f:
V
0 0
:'
• A· .:
~ <08
.'a:.I
• v
Co
$$
••
~ e.!
(j
20
l-
• 0
•••
0 0
V
V
.'
•• 't
l;. A
DD
0
V~
0 0
'4.6 ~
V
~ ¢
.
30
~
• ... ~
0 0
V
00
••
tl.
00
'Iv
0 •
0 0
• • L.·~
~V
0 (I
] 0
,.....
, l;.
l;.
~t
9 '!v
, (j
40
•
•••• A
l;.
V
0 oW
> 0
-:.:
....
t-
l;.~
v
~ 0
V
0 0
0 ••
~
V
.~
.. ~b.O
Vv
• •
~~
V °
V
.... ~~
. D~
V
50
• ••
• 6 ~
V
DO
0
• ....
D
0 V
•• •
•
• V
0
fJlD
0
D
• •••
~~ c
60
•
l;.
V
V
SA
UN
AS
TE
ST
SIT
E
I'.
t:. 4.
V ~
70
I-
AP
-IO
OO
DR
ILL
RIG
t:.\
. °
a-T
OO
TH
C
RO
WD
-OU
T B
IT
'1 0
rP
80
l-
• B
CC
-C
B
LOW
ER O
N A
NO
•
• ~ 8&
V
v v
c i
• BC
C~D
FU
LL
TH
RO
TT
LE
• •
~~O t
DO
•
BC
CE
••
t:§ v
0
0
90
I-
o B
CC
-f
o~
.;:
o B
CC
-G
BLO
WE
R O
FF A
ND
/OR
•
• V~
0rC
lJ
. B
CC
-H
RE
DU
CE
D
TH
RO
TT
LE
~
V;V
Dc
Q
B
CC
-I
• D
100
I .,
A R
o 0
0
10
100
UN
CO
RR
EC
TE
D
BE
CK
.ER
B
LOW
CO
UN
T,
Na
FIG
. 46
EF
FECT
OF
BLOW
ER E
LIM
INAT
ION
AND/
OR R
EDUC
ED T
HROT
TLE
ON B
ECKE
R BL
OWCO
UNT
AT
SALI
NAS
TEST
SIT
E
0
.,
10
00
-...J
W
1000
100
CD Z 1--Z ~ o
~ ..J CD
II: IAJ ¥ <.J IAJ CD
10
'0 2 4 6
I'
/"
I' , .1 , \ " \~~
\
'~
1', 0, ~QI .... -
~~ ..... ... • •• • 1'-' .. I.J'
SAUHtS TEST SITE (elevation 50 ft.)
Depth Interval = 29 - J4 ft .
• • • Blower-Qn and Full Throttle Combustion
O<>~V Blower-Gff and/or Reduced Throttle Canbustion
a 10 12 14 16 18 20 22 24 26
BOUNCE CHAMBER PRESSURE (psiql
FIG. 47 EFFECT OF ENERGY REDUCTION ON THE BECKER BLOI~COUNT - BOUNCE CHAMBER PRESSURE RELATIONSHIP FOR SALINAS TEST SITE (Depth Interval = 29-34 feet)
74
28
1000
100
III Z ..... Z ~ o
~ ..J CD
a:: ..... :II: U ..... CD
10
.v
" v t'V' _v
' ... ~
, ()
~ <
75
L'.
0
~..: 1-' .. I~ ... ,.. , :~ ~ ... -
~LINAS TEST SITE (Elevation 50 ft. J
Depth Interval = 48 - 52 ft •
• • • Bloller~ ana Full Throttle Combustion
o <)6V' Bloller-Off and/or Reduced Throttle Combustion
10 2 4 6 8 10 12 14 16 18 20 22 24 26 28
BOUNCE CHAMBER PRESSURE (psigl
FIG. 48 EFFECT OF ENERGY REDUCTION ON THE BECKER BLOWCOUNT - BOUNCE CHAMBER PRESSURE RELATIONSHIP FOR SALINAS TEST SITE (Depth Interval = 48-52 feet)
1000
100
ID Z , . .Z ::l o u
~ ..J CD
II: L&.I ~ U L&.I CD
/0
.. .. ~
,. ~J ~~
76
.... r.,.. 1- ~ ... ~ " .
~ .. ••
SALlHIIS TEST SITE (Elevation 50 ft.)
Depth Interval = 65 - 69 ft •
• •• Blorrer4l and Full Throttle Combustion
C06V Blorrer-Dff and/or Reduced Throttle Combustion
10 O! 4 6 8 10 IO! 14 16 18 O!O o!o! 0!4 0!6 28 BOUNCE CHAMBER PRESSURE (psigl
FIG. 49 EFFECT OF ENERGY REDUCTION ON THE BECKER BLOWCOUNT - BOUNCE CHAMBER PRESSURE RELATIONSHIP FOR SALINAS TEST SITE (Depth Interval = 65-69 feet)
1000
III Z
..: .Z :l
8 ~ ..J II)
a: 10.1 x Co) 10.1 II)
100
10
1 o
77
I
N '\.
'\.
dz .. ~'" 4W .. ~ , IV}( ~ ! ...
~1 ~ .. I ~ I I
I ,
SALIHIlS TEST SITE (Elevation 50 ft.)
Depth Interval = 7J - 77 ft •
• • • Blower-On and Full Throttle Combustion
CJ06'V Blower-Dff and/or Reduced Throttle Combustion
2 4 6 8 10 12 14 16 18 20 22 24 26
BOUNCE CHAMBER PRESSURE (pligl
FI G. 50 EFFECT OF ENERGY REDUCTION ON THE BECKER BLOWCOUNT - BOUNCE CHAMBER PRESSURE RELATIONSHIP FOR SALINAS TEST SITE (Depth Interval = 73-77 feet)
28
78
1000
t ~ \ 1i
\ , ~ .... 100
, <...l
~ C. , ~Q" ~ ....
... t- ... ..... ~ P-'" -!I
10
SIU.l,o.;qS TEST SITE (Elevation 50 ft.)
Depth Interval = 95 - 99 ft .
• • • Blower~ and Full Throttle Combustion
0<> tI. '\7 Blower-Dff and/or Reduced Throttle Combustion
10 2 4 6 8 10 12 14 16 18 20 22 24 26 28
BOUNCE CHAMBER PRESSURE (psigl
FIG. 51 EFFECT OF ENERGY REDUCTION ON THE BECKER BLOWCOUNT - BOUNCE CHAMBER PRESSURE RELATIONSHIP FOR SALINAS TEST SITE (Depth Interval = 95-99 feet)
79
about a 40 percent reduction in potential energy (4060 ft.-lb./6810 ft.-lb.).
Such lack of agreement raises serious questions concerning the applicability
and validity of the potential energy chart shown in Figure 29B, especially as
a basis for correcting the blowcount for different combustion conditions.
Evaluation of Energy Effects
During each cycle of the hammer, the load developed Ln the casing is
composed of three elements:
1. A Precompression Force
2. An Impact Force
3. An Explosive Force
The precompression force LS a gas force caused by the compression of aLr
and fuel in the combustion chamber as the ram travels downward towards the
anvil. The impact force results from the impact of the ram on the anvil. The
explosive force comes from the combustion of the fuel and the expansion of
resulting gases. An idealized representation of the force developed Ln a long
casing during each stroke, developed by Rempe and Davisson (1977) is
illustrated Ln Figure 52. During each stroke, the force is zero until the ram
closes the combustion chamber ports on its downward path. As the ram travels
further downward, the force due to gas compression gradually increases. The
force increases sharply at impact and then decreases gradually during gas
expansLon. When the ram travels far enough upwards to open the combustion
chamber ports, the force in the casing is again reduced to zero. The force
time curve can be integrated to get the net energy delivered to the casing.
This net energy should be some percentage of the available potential energy of
the ram and the combustion energy. However it should be recognized that in
the sequence of load development effects described above, .there is probably a
I CJ u ~
Lf "0 C .., .c CD -e_
Q.
I ·
Impact
Port Closure
Compre ssion
Separation
Exhaust
Expansion
100- 250 milliseconds
Time .. ·1
FIG. 52 IDEALIZED FORCE TIME-HISTORY EXPERIENCED IN A LONG CASING (from Rempe and Davisson, 1977)
80
81
severe kinetic energy loss when the air and fuel are compressed ~n the combus
tion chamber prior to impact of the ram on the casing.
The potential energy charts developed by ICE and shown in Figure 29B
were based on the assumption that the total potential energy ~s the sum of the
potential energy stored in the bounce chamber and the potential energy of the
ram determined by the product of its weight and its height of fall from the
top of its stroke (WH). This sum (represented by an equivalent stroke) is the
total potential energy of the ram. However, just as the air ~n the bounce
chamber pressure acts as a spring storing extra potential energy, the action
of the ram travelling downward and compressing the air and fuel in the combus
tion chamber acts as a cushion which slows down the ram so that the kinetic
energy at impact is severely reduced. It was pointed -out by Tony Last, ICE
representative, that the amount of energy lost in this way may be only a func
tion of the atmospheric pressure and the dimensions of the combustion chamber
(Ref. 16). Thus, for a particular atmospheric pressure and diesel hammer
type, the energy loss due to cushioning effects would be essentially constant
and could be estimated using the same procedures used to evaluate the energy
stored in the bounce chamber (See Appendix). For the atmospheric pressure at
sea level (14.7 psia) and the ICE 180 diesel hammer, the energy lost by com
pression of gases in the combustion chamber is found to be approximately
3810 ft-lb. This energy loss is a substantial portion of the potential energy
and it leads to the actual kinetic energy of the ram at impact (i.e. potential
energy m~nus compression energy loss) being significantly less than the poten
tial energy of the ram at the top of its stroke.
The implications of this energy loss are illustrated 1n Table 3 where
the kinetic energy of ram impact is presented for a range of bounce chamber
pressures. For a bounce chamber pressure of 20 psig, the theoretical
Table 3: Potential and Impact Kinetic Energies for Sea Level
Bounce Chamber Pressure
(psig J
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Potential Energy
(ft -lb)
4060
4370
4680
4970
5250
5530
5800
6060
6320
6560
6810
7050
7280
7500
7730
7940
8160
8360
8580
Energy Loss
(ft-lbJ
3810
3810
3810
3810
3810
3810
3810
3810
3810
3810
3810
3810
3810
3810
3810
3810
3810
3810
3810
Ram Inpact Kinetic Energy
(ft-lbJ
250
560
870
1160
1440
1720
1990
2250
2510
2750
3000
3240
3470
3690
3920
4130
4350
4550
4770
82
83
potential energy is 6810 ft-lb but the impact kinetic energy is probably only
about"3000 ft-lb. For a bounce chamber pressure of 10 psig, the theoretical
potential energy is 4060 ft-lb but the net kinetic energy is probably only
about 250 ft-lb. The ratio of potential energies is 1.67; but the ratio of
the impact kinetic energies 1S 12. A comparison of the impact kinetic energy
ratios would help explain why the blowcount increases so markedly with only
moderate decreases in bounce chamber pressure. Figure 53 shows the same data
presented previously for the 29 to 34-foot depth interval at the Salinas Test
Site, illustrating the very large increase in blowcount which results from
energy decreases. Also shown is a line representing the increase predicted by
using the ratio of net kinetic energies. The agreement between the test data
and the prediction is relatively-good. Comparisons for other depth intervals
give similarly good agreement.
Since the impact kinetic energy appears to control the resulting blow
count, it would appear that the precompression and explosive forces do not
play important roles in the direct driving o~ the casing. This is not totally
inconsistent since the precompression force 1S probably insufficient to drive
the casing into the soil. However, the explosive force cannot be considered a
minor force. A possible explanation for its apparently small effects, sug
gested by Fuller (1983), is that most of the explosive energy is directed
towards raising the ram for its next stroke. If this is so, then the explo
sive force would have a negligible influence on the casing penetration during
any given cycle.
Effect of Elevation on Energy and Bounce Chamber Pressure
Operators of the Becker drill rigs have long believed that higher eleva
tions reduce the amount of energy developed by the diesel hammers. This
belief was fostered partly because oxygen levels are known to be lower at
1000
100
CD Z
t·: Z :I o ~ o ~ CD
II: 1&.1 ~ U 1&.1 ID
10
I"
/'
~ \v ~i
I"-
" .'6.. I'
c ~
~
~ • -r;.;. i.: I. • 1"- ~
• ~ .s.4UMS T£ST SITE (Elevation 50 ft.)
Depth Interval = 29 - J4 ft •
• • • Blower-On and Full Throttle Combustion
C <> 6. V Blower-Off and/or Reduced Throttle Combustion Blowcount Path Predicted - Using Ratios of lJrfJact
. Kinetic Energy '0 2 6 8 10 12 14 16 18 20 22 24 26 4
BOUNCE CHAMBER PRESSURE (psigl
FIG. 53 COMPARISON OF ACTUAL BLOWCOUNT INCREASES WITH PREDICTIONS BASED ON RATIOS OF IMPACT KINETIC ENERGY FOR SALINAS TEST SITE (Depth Interval = 29-34 feet)
84
28
85
higher elevations. In addition, the operators have noted that the bounce
chamber pressures appear to be lower at higher elevations. For example, ln
dense soils at 6000 feet elevation, the bounce chamber pressures rarely
exceeded 20 pSlg. However, at sea level, bounce chamber pressures often
reached 28 psig in dense soils. This behavior can also be observed ln
Figure 54 by examining the full throttle constant combustion rating curves for
the Salinas (Elev. 50 feet), Denver (Elev. 5300 feet), and Mackay (Elev. 6100
feet) Test Sites. This figure suggests that an increase in elevation moves
the rating curve to the left (i.e. causes a decrease in energy).
There is a correction required, however, in using the bounce chamber
pressure as an indicator of energy for different elevations. This correction
is needed because the atmospheric pressure lS not the same at all elevations.
For example, at sea level, the atmospheric pressure is usually around
14.7 psig. At an elevation of 6000 feet, the atmospheric pressure is around
11.7 psig. This affects the calculations for potential energy, energy lost
during combustion chamqer compression, and the resulting impact kinetic
energy. Table 4 shows the various energies calculated for an elevation of
6000 feet. Figure 54 shows the impact kinetic energy as a function of bounce
chamber pressure for both elevations. For the same bounce chamber pressure,
the net kinetic energy at 6000 feet is in fact, significantly greater than
that at sea level. For example, the net kinetic energy.at a bounce chamber
pressure of 10 psig at sea level is only about 16 percent (250/1600) of the
energy developed for the same bounce pressure at the 6000-foot elevation.
To correct for the effect of different atmospheric pressures on the net
kinetic energy, it appears that the best approach is simply to make an adjust
ment to the bounce chamber pressure value. For example, if the blowcount and
bounce chamber pressure relationships developed at sea level are adopted as a
86
1000
ELEV. 5~00 feet . ELEV. 610? 'eet . ELEv. 50 feet
100
• Z ,..-Z ::::) o
~ -' III
a:: '" ~ ~ III
10
. I
• : I .
I . .,' 1I .- ,/
/ . . 1-/
.- ,/
V7 . / .. ,,'
/ .
~ ..... . . "
,/
r7 ~.
/
,
2 4 6 8 10 12 14 16 18 20 22 24
BOUNCE CHAMBER PRESSURE lpsig)
-- - UNCORRECTED FULL THROTTLE CONSTANT COMBUSTION RATING CURVE FOR MACKAY TEST SITE (ELEV. 6100 lee')
.... ....... UNCORRECTED FULL THROTTLE CONSTANT COMBUSTION RATING CURVE FOR DENVER TEST SITE (ELEv. 5300 lee')
- - - - - UNCORRECTED FULL T}1ROTTLE CONTANT COMBUSTION RATING CURVE FOR SALINAS TEST SITE (ELEv. 50 fee')
/ ~.
26
FIG. 54 UNCORRECTED FULL THROTTLE CO~1BUSTION RATING CURVES FOR SALINAS. DENVER, AND MACKAY TEST SITES
~ ,
28
Table 4: Potential and Impact Kinetic Energies for Elev. 6000'
Bounce Chamber Pressure
(psig)
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
- Potential Energy
(ft -lb)
3150
3560
3950
4290
4630
4960
5270
5570
5870
6150
6420
6690
6940
7190
7430 .
7670
7900
8120
8340
Energy Loss
(ft -lb)
3030
3030
3030
3030
3030
3030
3030
3030
3030
3030
3030
3030
3030
3030
3030
3030
3030
3030
3030
Ram Irrpact Kinetic Energy
(ft -lb)
120
530
920
1260
1600
1930
2240
2540
2840
3120
3390
3660
3910
4160
4400
4640
4870
5090
5310
87
88
standard, then bounce chamber pressures obtained at higher elevations would
need to be adjusted upward by some amount to represent the appropriate kinetic
energy level. For an elevation of 6000 feet, this adjustment would range from
about 3.7 at a bounce pressure of 6 psig to about 6.2 for a bounce chamber
pressure of 20 psig (See Figure 55).
Shown again in Figure 56 is the constant combustion rating curve for
full throttle combustion developed at the Salinas Test Site (El. 50). Also
shown are the full throttle rating curves for the Denver and Mackay Test Sites
after being corrected to sea level conditions as described above. The cor
rections used were those shown in Figure 55 for conditions at 6000 feet eleva
tion. Application of this correction brings the rating curve for the Denver
Test Site (Elevation 5300 feet) into excellent agreement with the rating curve
determined for the Salinas site. Although the combustion rating curve for the
Mackay Test Site remains significantly higher than the others, it is moved
much closer to the Salinas curve after correction. Whether the remaining
difference between the Mackay and the Denver and Salinas curves is due to the
reduced partial pressure of oxygen at Mackay, or possibly to the use of lower
grade fuel at that site remains unknown. However, it is possible to conclude
that changes in elevation do not change the rating curve as much as previously
thought.
Adoption of a Calibration Combustion Rating Curve
Under ideal circumstances and conditions, the best way to calibrate
energy effects would be to measure transmitted energies within the casing
steel. Consideration was given to attempting such measurements using
accelerometers, strain gauges, etc., but this approach was finally rejected
for the following reasons:
89
6000p---------~--------~----------~--------~--------~
5000~--------~--------_+----------~--~~--_r--------~
4000 ~ -I -->-<.!) a:: I.&J 2
3000 UJ
U I-I.&J 2 ::.: ~ u « 2000 a. ~
1000 ~----~~~---- ~----4-----------+_----------+_--------~
5 10 15 20 25 30 BOUNCE CHAMBER PRESSURE (psigl
FIG. 55 ESTIMATED KINETIC ENERGY OF RM1 AT ANVIL H~PACT
90
IOOO~~~~~~r-~~~~r-r-r-r-r-r-r-r-r-,r-r-r-r-r-r-~~ .
• z .....z ~ o u ~ 9 CD
,OO~
II: \&J ~.
:rl cD 10 I-
MACKAY TEST SITE
DENVER TEST SITE
• • •
.
: ,-I · , -.. " -
/ ... , -:, / • .,/' SALJ NAS -
~ TEST I ~' SITE_
/ tfo· ,-. / ~ ...
/ ,~ ...• / ,' •.•.
/ ~~' .. -,/ '
-
-
-
'0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 BOUNCE CHAMBER PRESSURE MEASURED AT SEA LEVEL (BP)sL (psig)
FIG. 56 FULL THROTTLE COMBUSTION RATING CURVES FOR SALINAS. DENVER. AND MACKAY TEST SITES CORRECTED TO SEA LEVEL ATMOSPHERIC PRESSURE
91
1. Employing sophisticated transducers .requires specialized equipment
and experience. It also requires assumptions and simplifications
in order to evaluate energy levels.
2. There is some doubt that the equipment and theories would be able
to adequately account for the effects of the inner casing floating
within the outer casing.
3. Using sophisticated transducers would slow down the drilling
process and reduce some of the economic attraction of the Becker
process.
4. The wide variety of pile hammers and pile s~zes used in the pile
driving industry is not present with the Becker equipment. The
Becker equipment uses only one kind of hammer, only one or two
types of "pile" sizes and impedances, and only one kind of hammer
cushion. Thus variations from one site to another should not be
very large so long as a standard procedure is followed.
5. Using the bounce chamber pressure gauge together with field data
regarding the effect of combustion effects on blowcount was
considered to be an adequate way of handling energy effects.
Thus, although the exact magnitude of the energy transmitted down
the casing may not be known, it is possible to monitor the impact
energy and then predict the effect on the measured blowcounts.
Figure 57 shows an idealization of different constant combustion rating
curves and the blowcount paths for constant depths in the same material that
range across the rating curves. As has been shown previously, several
different combustion rating curves can exist for the same hammer operating at
the same site, depending on the throttle settings. With different combustion
conditions, the resulting blowcount can be radically different. Therefore, in
92
100~----~----~----~----~----~----~----~----~----~----~----,
CD Z 1-Z ::l o U ~ 10 ...J CD
a: w ~ u w CD
I 2
~ ~
::z: I-a.. lIJ 0
12 CHAMBER
22
O~--------~----------~---------T----------~--------~
10
20
30
40
50 0 10 20 30 40 50
BECKER BlOWCOUNT. NS
FIG. 57 IDEALIZATION OF HOW DIESEL HAMMER COMBUSTION EFFICIENCY AFFECTS BECKER SLOWCOUNTS
24
93
order to use the Becker Pe~etration Test as an indicator of soil properties,
it is necessary to adopt one combustion rating curve as a standard and develop
corrections for combustion curves that are different from that standard. The
constant combustion rating curve adopted in this research program is that for
full throttle combustion developed at the Salinas Test Site (Figure 32). This
curve was chosen because it represents the highest energy (i.e. the lowest
blowcount curve) observed in any of the field tests and corrections to this
curve will result in correcting blowcounts Ln only one direction (i.e. reduc
Lng blowcounts to allow for lower energies employed under other conditions.
Blowcounts which fallon this calibration curve, or which have been corrected
to fallon this curve, will here-after be designated as corrected Becker blow
counts and will be given the symbol NBC'
The development of correction curves for lower energy combustion condi
tions made use of both field measurements and calculations based on deter
minations of kinetic impact energy. Figure 58 shows the blowcount paths
measured in the field for different combustion conditions at different sites.
These curves were previously presented in Figures 35-40, 43-45, and 47-51, but
in Figure 58 they have been corrected for elevation where necessary. Also
shown in Figure 58 are blowcount paths based on ratios of impact kinetic
energy. The agreement between the two sets of data is relatively good and
from these data, the correction curves shown in 59 were drawn and adopted for
use Ln this study.
To use the correction curves, it is simply necessary to locate each
uncorrected test result on the chart shown Ln Figure 59, using both the
uncorrected blowcount and the bounce chamber pressure, and then follow the
correction curves down to the standard rating curve AA, to obtain the cor
rected Becker blowcount, NBC' For example, if the uncorrected blowcount was
1000
100
10
1
....
~A
o 2 4 6
1\ ~ \ \ \ \
[ f'\. I~\ 1\ ~
~~ " ,
\ ~ t'-. ,
\ r-....
~ ~ ......
r--.... ,
~ I'-... r--.... ",
r-... '" j'... r-... ",
\ ~
, i""- t--r- '"
\ \ , r-... p...., -1,\ .....
'" , ~, i""'-o.. I \ - ... ~ " --~ i'- " .. ~
. " -. 7
\ '\ ~. r.....:, ~ ~ '" ~ " "
\ "\ , .... i~, ' ,~ ~ ~ '~ ,
"
"" ~ ...... , ~41 ••
, .~
, ..... ~" / ..:. '. , ,
~ ~ ;-. ... ..... V . ~
1'-_ ~ .. ~- / I
. ' .. ~, , "\ N .
" V " " V ~ ~ I, ~ ~ / ".
"" -~
roo.. '" v ..... 1 [7
~ '" v :, " V'
~
V ~
8 10 12 14 16 18 20 22 24 26 BOUNCE CHAMBER PRESSURE (psigl
.. "...... DENVER TEST SITE IFIGURES 35-40)
- - MACKAY TEST SITE (FIGURES 43-45)
-- - - SALINAS TEST SITE (FIGURES 47-51)
PREDICTION 8ASED UPON RATIOS OF IMPACT KINETIC ENERGY
94
1\
28
FIG, 58 PATHS OF BECKER BLOWCOUNT INCREASES FOR DECREASING HAMMER ENERGY BASED ON FIELD DATA AND RATIOS OF IMPACT KINETIC ENERGY
1000
100
• Z
.... -Z ::l o u
~ ....I ~
II: !oJ :.: u !oJ ~
10
I o 2
95
l\ i'. BLOWCOUNT CORRECTION CURVES FOR REOUCED COMBUSTION -.--
\ \
~ '" ~FICIENCIES D \ I~ I" " ~ k \ I'. r-.... 1\ :---...... .........
~ ~ i'. ........ ~
r-....... -... --'I. --..~ A-'\. " '" ...... - J
" '\ .... ....... """ I\. -""'- ......... --,.... ../
\ \ \ ...... f"... ...... 1'.... ./,0
1\ I\. ~ ." .......... ~ --"r--~ ~~
~ '\ \ \ ,\ ~ .........
r-.... """ r-.... ./r V<..~ ...... 11-,
~ \ \ ~ "" I'. 1'. ~P f\ ~ f\. f'.. ~ t-.... l/.: o'~
'\ '\ ~ " i' "" "- ~~ 1\ ~ ~ ~ ~ " i' ~ ~ roo.. ~ r--... ~ L ~
.... '" L" be\
'" i"- i"- _0' f'- .... ......... /,..",
i'o.. "-~
'" ~t:: ~v
/. ~'" A c,I.J
NOTE I ALL BECKER BLOWCOUNTS FALLING ON OR CORRECTED TO CALIBRATION CURvE ARE DESIGNATED AS CORRECTED BECKER BLOWCOUNT, Nee I
4 6 8 10 12 14 16 18 20 22 24 26 28
BOUNCE CHAMBER PRESSURE AT SEA LEVEL, BPsL (psigl
FIG. 59 CORRECTION CURVES ADOPTED TO CORRECT BECKER\BLOWCOUNTS TO CONSTANT COMBUSTION CURVE ADOPTED FOR CALIBRATION
96
43 and it was obtained at sea level with a bounce chamber pressure of 18 psig,
then the corrected Becker blowcount would be 30, as shown in Figure 60. If
the bounce chamber pressure requires a correction to sea level, that cor
rection should first be made and then the corrected blowcount determined as
before. For instance, if the uncorrected Becker blowcount was 24 and it was
obtained at al elevation of 6000 feet with a bounce chamber pressure of
12.5 psig, the bounce chamber pressure is first corrected to sea level condi
tions by adding 5 psig (See Figure 55). Using an uncorrected blowcount of 24
and a corrected bounce chamber pressure of 17.5 psig then yields a corrected
Becker blowcount of 18 (Figure 60).
Effect of Drill Rig Type on Becker Blowcount
Becker Drills, Inc. employs principally two types of drill rigs to
perform the Becker Penetration Test. The older rig ~s designated the B-180
drill rig (it is also known as the HAV-180 rig) and a"newer model, developed
in the mid-70's, which is designated the AP-lOOO drill rig. Both rigs employ
the same model of diesel hammer, an ICE Model 180. The main difference
between the drill rigs is that the mast of the newer AP-lOOO rig is more
elaborate and the way the hammer is hung onto the mast is more complicated.
On the older B-180 rigs, the hammer is mounted on wear blocks and follows the
casing by weight alone. There are cables mounted to the ~op of the hammer
frame for raising the hammer with hydraulic rams, but none for pulling down on
the hammer frame. On the newer AP-IOOO rigs, there are cables connected to
both the top and the bottom of the hammer frame. These cables are connected
to hydraulic rams and, in addition to being able to raise the ram back up the
mast, they allow the hammer to be pulled down onto the casing during driving.
This "pull-down" static force is used mainly during the driving of
1000
100
• z .. : z ~ o u
~ ..J m a:: ~ ~ u ~ It!
10
I a 2
97
I, r\. BLOWCOUNT CORRECTION CURvES
1\ \ ~ FOR REDUCED COMBUSTION -r--
" ~FICIENCIES D
\ 1,\ 1"-i'-
I"--. 1"-~ \ 1\ " i'. )'-....
\ 1\ '" r-.... r--.... ......... ........ -"- ...... A-'\ 1,\ 1"- ....... /
\: \: " "- ........ ~ f\ ~ "' ......... r-- /
\ \ '\ '\ r"... ....... r--.... /. 0"-
t\ \~ f': " ""'tc ~ ........ t-.. to-... ~~
1\ \ \ \ \ " '" "- .......... r-..... Vr VC" ...
r--, ~ \ \; "\ " 8 i'. ~~
~ l\ ~ ~ ~ A ~'\
~ ......... 0
1\ '\ " ~ ~ ......
" ,~
f\ " ~
" ~ i'-.
~ ~
~ ~ i'... ~ ~ LA '" " " :('\~
'" " " ~ .. i'o.. "' ~r'-r-.... Vri: \!''' / ~~
A <;.0 NOTEI ALL BECKER BLOWCOUNTS FALLING ON OR
CORRECTED TO CALIBRATION CURVE ARE DESIGNATED AS CORRECTED BECKER BLOWCOUNT, Nec I
6 8 10 12 14 16 18 20 22 24 26 28
BOUNCE CHAMBER PRESSURE AT SEA LEVEL, BPsL Ip5igl
FIG. 60 EXAMPLES ILLUSTRATING THE USE OF CORRECTION CURVES TO CORRECT BECKER BLOWCOUNTS
98
particularly stiff material with, say, more than 200 blows per foot, Ln order
to reduce the number of blows during driving.
Most of the Becker Penetration Testing carried out Ln this investigation
were performed with an AP-lOOO drill rig (Rig. No. 57). Even though the pull
down option was never used during these studies, it was decided to investigate
whether the use of the other type of rig, a B-180, would produce a different
result. Consequently, the soundings performed at the San Diego Test Site were
performed with a B-180 drill rig (Rig No. 11). The results from this site
were compared to those obtained at the Salinas and Thermalito sites where the
AP-lOOO rig was used. At all three sites, good quality SPT results were
available. Surprisingly, the Becker blowcounts at the San Diego s~te appeared
relatively low when compared to the results from the other two sites. The
older B-180 rig appeared to give Becker blowcounts that were only about one
half of the values that would be indicated for the same SPT blowco.unts from
the Salinas and Thermalito sites. The result indicated that the B-180 rig was
alm~st twice as efficient at transmitting hammer energy as was the AP-lOOO
rig.
To further investigate the effect of different drill rigs on Becker
blowcounts, 2 pairs of soundings were performed at the Denver Test Site. One
paLr of soundings was performed using the same AP-lOOO rig (Rig. No. 57) as
that was used at the Salinas and Thermalito Test Sites. Another pair of
soundings, performed Ln close proximity to the first pair, was carried out
using a B-180 drill rig (Rig. No. 55), a different rig than the one used at
San Diego). Figure 61 shows a photograph of the two different rigs used at
the Denver Site. The resulting uncorrected Becker blowcounts are presented in
Figure 62. As may be observed, the AP-I000 rig gave uncorrected Becker blow
counts that were consistently 60 percent higher than those obtained with the
FIG. 61 PHOTOGRAPH ILLUSTRATING THE MORE COMPLICATED MAST OF THE AP-1000 DRILL RIG (LEFT) COMPARED TO THAT OF THE B-180 DRILL RIG (RIGHT)
99
DEPTH (feet)
100
o ~--------~--------~--------~--------r---------r---~
10
20
30
40
50
DENVER TEST SITE 6 SIB-inch O. D. PLUGGED B-TOOTH CROWD-OUT BIT
..",~ . .".". ---- --...... ;;.;::-:;:::;:-::;::=:::::;~=========::3 -----~~-'" I
"'- - -\.. "" .... "" ' .. -"" --" .......... ' ..", .... - -- -. - ......
\ / / -" ..... ... .....
........ / .......... ..... .... ....::' ... ====--=:--, --< ,-- - " -- -'...-- -" .-,- - , ..................... , -.... /'
- > ',. / .... ~< I I
/"" .... "" "" , ",," ... '- ---" ~~::.-....-=-=:;::::t'~--- --:;-..... - .... 1,/
\ "I "-.... \
... r -
2
BCC-I AP-1000 rig BCC-2 AP-IOOO rig
BCC-3 8-180 rig BCC-4 8-180 rig
swGW
CL
I---~
60~--------~--------~--------~----------------~ o 20 40 60 80 100
I.JtlCORRECTED BECKER BLOWCOt.#lT, Na (blows/foot)
FIG. 62 COMPARISONS OF UNCORRECTED BECKER BLOWCOUNTS OBTAINED WITH DIFFERENT DRILL RIGS AT THE DENVER TEST SITE
101
B-180 rig. These results are similar in form to those obtained at the San
Diego, Salinas, and Thermalito Test Sites described above.
Figure 62 indicates that the B-180 is roughly 60 percent more efficient
~n transmitting hammer energy than is the AP-IOOO rig. However, the
efficiency difference refers only to uncorrected blowcounts. An additional
factor needs to be considered because the B-180, giving a lower blowcount, ~s
operating at a lower bounce chamber pressure and, therefore with a lower
energy (see previous discussion). This effect can be accounted for by cor
recting the bounce chamber pressures to sea level and using Figure 59 to
obtain corrected Becker blowcounts, NBC. After making these corrections, the
data can be plotted in the form shown ~n Figure 63. In this figure, the mean
corrected Becker blowcount values for each pa~r of soundings are plotted
against each other for each foot of penetration between depths of 11 and 55
feet. Figure 63 shows that after correcting for hammer energies, the AP-IOOO
drill rig generally gives a blowcount about 50 percent higher than the B-l80
drill rig.
The reason why the older B-l80 drill rig ~s roughly 50 percent more
efficient in transmitting hammer energy is not totally clear. Both the B-180
and the AP-lOOO rigs employ the same type of diesel hammer. The only possi
bility that is readily apparent ~s that the more complicated cable and hydrau
lic ram arrangement on theAP-lOOO rig prevents the hammer from following the
casing during driving as well as the cable system on the B-l80 rig. Figure 64
shows a photograph of the cable and hydraulic support system for the AP-lOOO
rig. It seems likely that this cable system is absorbing a significant por
tion of the hammer energy. Support for this theory comes from direct observa
tion of the two rigs in action. During driving with the B-l80 rig, there ~s
relatively little bounce or oscillation of the hammer frame as the hammer
100~--------~1----------~1--------~1~--------~1--------~
o o 51 I
Ct: ~ 0_
80 r-
LL. u ~ GI ZZ =>""': 60 rOC) u-~Ct: O..J ..J..J IXlji 00 W ~a:: uw ~ ~ 40 r-Ct:W 0 111 u o zO «0 w7 :Eo..
«
20 I-
I
, I
I 1 ,
. , .,,' -.~
• fI"\.1.
I·
• • I .. , I , I
. ' I , , •
, (NacIAP-IOOO: 1.5 It (Nacls-18o
NOTE: EACH POINT REPRESENTS THE MEAN OF TWO AP-IOOO BECKER BLOWCOUNTS CORRECTED TO THE CALIBRATION COMBUSTION RATING CURVE VS. THE MEAN OF TWO B-180 BECKER BLOWCOUNTS CORRECTED TO THE CALIBRATION COMBUSTION RATING CURVE.
-
-
-
-
o~~ ________ ~r _________ ~I ______ ~r ________ ~I ________ ~ a 20 40 60 80 100
MEAN CORRECTED BLOWCOUNT FOR B-180 BECKER DRILL RIG, (Nacla-Iso
FIG. 63 EFFECT OF DRILL RIG ON CORRECTED BECKER BLOWCOUNT
102
FIG. 64 PHOTOGRAPH SHOWING THE HYDRAULIC AND CABLE SUPPORT SYSTEM FOR THE DIESEL HAMMER ON THE AP-1000 DRILL RIG MAST
103
104
moves down the mast. However, during driving with the AP-I000 rig, the hammer
frame bounces up and down on its cables, thus indicating that the cables are
indeed absorbing some of the energy.
Effect of Casing Size on Becker Blowcount
As previously discussed, the Becker casings most widely used for pene
tration testing are available in two sizes. The casing used predominantly ~n
Canada has a 5.5-inch 0.0. whereas the casing used predominantly in the
United States has a 6.6-inch 0.0. To explore the effect of casing diameter, a
pair of 6.6-inch plugged bit soundings were performed in the same proximity as
were a pair of 5.5-inch plugged-bit soundings at the Denver Test Site. A
comparison of the uncorrected Becker blowcounts obtained with the different
bit sizes is presented in Figure 26. This figure indicates that a plugged
5.5-inch crowd-out bit gave a blowcount that was roughly 60 percent of that
produced by a plugged 6.6-inch crowd-out bit. However, as with the data
involving different drill rig types, the 60 percent ratio does not include the
effect of differing bounce chamber pressures and energies. Because the
smaller casing gives a lower blowcount, it is operating at a lower bounce
chamber pressure and, therefore lower energy. As with the effect for
different drill rig types, this difference can be accounted for by correcting
the bounce chamber pressures to sea level and using Figure 59 to obtain
corrected Becker blowcounts. After obtaining corrected Becker blowcounts, the
data can be plotted in the form shown in Figure 65. In this figure, the mean
values of corrected Becker blowcount for each pair of soundings are plotted
against each other for each foot of penetration between depths of 11 and 55
feet. Figure 65 shows that after making the adjustment for different bounce
chamber pressures, the 6.6-inch casing generally gives a blowcount about 3
times higher than the smaller 5.5-inch casing. This is a rather large
100~--------~-----------r----------~----------~--------~
00
~ u CD
o:z 0-LL.t: ~aI Z
80
=>~ 60 o=> uO ~I 00 ...J3 alo 05 L&J ~o UL&J L&J en 40 0:0 O:...J OU U ~
Zu ctz L&J~I
co ICi
20
.. ~ ,
I , I
I ,
.. , I
I I .. ,' , . ,
I I ,.
e ,'.
I I
(NBC) 6.6 = 3.0 x (NBC) 5.5
NOTE: EACH POINT REPRESENTS THE MEAN OF TWO 5.5-INCH BECKER BLOWCOUNTS CORRECTED TO THE CALIBRATION COMBUSTION RATING CURVE VS. THE MEAN OF TWO 6.6-INCH BECKER BLOWCOUNTS CORRECTED TO THE CALIBRATION COMBUSTION RATING CURVE.
O~--------~----------~--------~----------~--------~ o 20 40 60 80 100 MEAN CORRECTED BLOWCOUNT FOR
5.5- INCH CLOSED CROWD-OUT BIT, (Nac)~.~
FIG. 65 EFFECT OF BIT DIAMETER ON CORRECTED BECKER BLOWCOUNT
105
106
correction, especially when the uncorrected results indicated only about a 60
percent increase. The large correction comes about because the bounce chamber
pressures for the two sets of data were very different. This suggests that
constant combustion rating curves are very different for different casing and
bit sizes despite combustion conditions being the same.
Effect of Casing Friction on ~ecker Blowcount
Conventional methodologies for pile design involve the determination of
resistances for both the bearing at the pile tip and for friction along the
embedded length of the pile •. Even for cohesionless soils, the resistance
attributed to friction along the pile length is often calculated to be a
significant proportion of the total supporting capacity of the pile. If these
components of static pile capacity were applicable during driving, then the
applicability of the Becker Penetration Test would be severely limited.
Fortunately, it appears that friction along a pile shaft may well drop to
minimum levels during driving, especially in looser sands and gravels (e.g.
Terzaghi, 1943; Peck et al., 1974). Some recent support for this concept is
also provided by test data reported by Mitchell (1985), who presented data on
the static resistance of 6-inch diameter casings vibrated into deep sand
deposits as well as the cone penetration resistance for the deposits. Com
parisons show that the relationship between the total static casing resistance
and the conventional cone penetration resistance (tip resistance) does not
change significantly wfth depth, thus indicating that casing friction had
minimal effects on the total casing resistance.
To examine the effect of casing friction on the Becker blowcounts, a
special redriving test was performed at the Mackay Test Site. After com
pletion of a 6.6-inch plugged-bit sounding, BCC-l, at a terminal depth of 43
feet, the casing was raised 5 feet up to the 38-foot depth level and redriven.
107
The original uncorrected blowcounts in this 5 ft depth range exceeded 200
blows per foot. However, as shown in Figure 66, the redriven blowcounts
dropped to zero (i.e. the casing and hammer settled under its own weight) for
a distance of more than 3 feet.
The above data would indicate that casing friction has only a m1nor
effect on Becker penetration resistance. The reason for this behavior may be
due to the disruption of the particle fabric during the undoubtedly severe
straining around the bit during penetration. Studies by Mitchell et ale
(1985) have shown that SPT and CPT resistance temporarily drops in sand after
densification by blasting despite the fact that the sand has significantly
increased in density. Another possibility may be that the gravel particles
arch around the casing and that this effect reduces the normal stress on the
casing. However, apparently low skin friction was also observed in the silty
sands at the San Diego Test Site. As shown 1n Figure 20, the two open-bit
soundings at this site developed relatively low and unrepresentative blow
counts below 30 feet. Sounding BOC-A actually developed blowcounts of zero
below 33 feet. However, a zero blowcount would not be possible if skin
friction were a significant factor because the casing must slide through the
upper 30 feet of silty sand no matter what the resistance at the tip. The
upper 30 feet consisted of sand of moderate density and there was no apparent
heave of soil into the bit through this interval. Despite going through this
material, the results from BOC-A indicate that the effect of casing friction
was very small.
It should not be concluded, however, that the friction on the casing 1S
zero just because there is a zero blowcount. It is important to note that the
diesel hammer weighs over 4500 pounds and that each 10-foot length of casing
weighs an additional 500 pounds. Nevertheless, the basic conclusion from the
o ,r--------~------~r_------_.--------,_------------------------------------_r--_,
10
20
DEP
TH
(fe
et)
JO
40 ~
Red
rjvl
ng
• BC
C-l
CLOS
ED
6.6-
lnch
CO
Blt
(O
rig
Ina
l D
rJ v
lnQ
)
o BC
C-l
CLO
SED
6.
6-ln
ch C
O B
lt
(Red
rlvl
ng a
fter
ral
s1ng
5 f
eet
from
bot
tom
)
50 I
I
a 10
20
)0
40
50
60
70
80
UNCO
RREC
TED
BECK
ER B
LOW
COUN
T, NB
FIG
. 66
UN
CORR
ECTE
D BE
CKER
BLO
WCO
UNTS
FR
OM
INIT
IAL
AND
REOR
IVIN
G TE
ST A
T MA
CKAY
TE
ST S
ITE
GW
110
II
n I~.
liD
t·
80
'.0
zo
o au
11
7 1
70
n
o
I-'
o ex>
109
above data is that, at least for cohesionless soils, casing friction has a
minimal effect on the Becker blowcount values.
110
Chapter 4
DEVELOPMENT OF A CORRELATION BETWEEN BECKER AND SPT BLOWCOUNTS
In the preceding chapter, it has been shown how different drilling pro
cedures and equipment can affect the Becker blowcounts. As summarized in
Table 5, the Becker blowcount can be changed significantly depending on how
the test is performed. This does not mean, however, that the test cannot give
meaningful results. Rather, it indicates the need to perform the test care
fully in a manner which will eliminate most of the potential variability.
Table 6 lists the equipment and procedure recommended for obtaining standard
values of corrected Becker blowcounts.
The principal purpose of performing all the investigations concerning
the Becker Penetration Test was to obtain a useful correlation between Becker
blowcounts and SPT blowcounts ip soils where both tests give meaningful
results. As described previously, the sites where good quality SPT tests
existed in sands and silts were the Salinas, Thermalito, and San Diego Test
Sites. The development of the desired correlation between SPT N-values and
Becker blowcount values at these sites involved three steps:
1. At each of the three sites, the uncorrected SPT blowcounts were
corrected to N60 blowcounts. The correction factors used to per
form this test were described previously.
2. The second step consisted of correcting the uncorrected Becker
blowcounts to NBC blowcounts. The procedure to perform this task
is outlined in Table 6. (Note: Both N60 and NBC data obtained at
less than lO-foot depths were multiplied by a correction factor of
0.75 to account for energy losses ~n the short length of drill
rods or casing.
Tab
le 5
: In
flu
ence
s o
f P
roce
dure
s an
d E
quip
men
t on
B
ecke
r B
low
coun
ts
VARI
ABLE
IN
FLLE
NCE
I.
DRI
LL
RIG
A.
AP
-IOO
O
(new
st
yle
) B.
8-
180
(old
sty
le)
(NaC
)AP
-100
0 =
1.5
X (
Nac
)B-1
80
II.
BLOW
ER
OR
SUPE
RCHA
RGER
(N
B)b
10w
er =
(0.4
to
0.8
) X
(N
B)n
o bl
ower
III.
TH
ROTT
LE
SETT
ING
IV.
CASI
NG
DIA
MET
ER
A.
5.5
-in
ch 0
.0.
B.
6.6
-in
ch 0
.0.
V.
BIT
PLU
G A.
P
lugg
ed C
row
d-ou
t b
it
B.
Ope
n C
row
d-ou
t b
it
Infi
nit
ely
va
ria
ble
(Nac
)6.6
= J
.O X
(N
BC)5
.5
Any
whe
re
betw
een
0 an
d in
fin
ity
(dep
ends
up
on
soil
ty
pe)
INVE
STIG
A TI
ON
1.
San
Die
go
Tes
t S
ite
2.
Den
ver
Tes
t S
ite
1.
2.
J.
Den
ver
Tes
t S
ite
Mac
kay
Tes
t S
ite
Sa
lin
as
Tes
t S
ite
1.
Mac
kay
Te
st
Sit
e
2.
Sa
lin
as
Tes
t S
ite
1.
Den
ver
Tes
t S
i te
1.
San
Die
go.
Sa
lin
as.
&
T
herm
alit
o T
est
Sit
es
2.
Den
ver
Tes
t S
ite
J.
Mac
kay
Tes
t S
ite
i--'
i-
-'
i--'
Table 6: Recommended Procedure for Obtaining Becker Blowcounts
EQUIPMENT
Drill Rig: AP-lOOO
Diesel Pile Hammer: ICE 180
Throttle Setting: Full throttle with blower on
Casing Diameter: 6.6-inch 0.0.
Drill Bit: Closed 6.6-inch 0.0., B-tooth Crowd-out
PROCEDURE
1. Measure Becker blowcounts and bounce pressures.
112
2. Correct bounce pressures measured at high elevations to equivalent bounce pressures at sea level.
3. Use corrected bounce pressure and Becker blowcount together with calibration chart (Figure 59) to obtain the corrected Becker blowcount, NBC
and, tentatively,
4. If Becker blowcounts were obtained using a B-IBO Drill rig, first use Figure 59 to obtain corrected Becker blowcounts, NBC. Then multiply the corrected blowcounts by 1.5 to obtain equivalent AP-lOOO rig corrected Becker blowcounts.
5. If Becker blowcounts were obtained using the 5.5-inch 0.0. casing, first use Figure 59 to obtain corrected Becker blowcounts, NBC. Then multiply the corrected blowcounts by 3.0 to obtain equivalent 6.6-inch 0.0. corrected Becker blowcounts.
113
3. The final step consisted of averaging both sets of corrected data
across depth intervals varying between 1 and 7 feet. The selec
tion of each interval size was based on the uniformity of blow
count data along the depth profile at each site.
The results of the development process for the Becker-SPT correlation
are summarized in Table 7 and plotted in Figure 67. Although there is some
scatter, the amount of scatter is significantly less than that found in pre
vious correlations. In addition, the data from the different sites agree
relatively well with each other.
The correlation curve shown ~n Figure 67 is based on a judged best fit
of the data. The trend of the curve suggests a roughly 1:1 ratio for cor
_rected blowcounts of less than about 20. This is consistent with some of the
previous correlations shown previously in Figure 10. However, for corrected
SPT blowcounts above about 20, the correlation curve bends downward. This
later trend is significantly different from that indicated by most of the
previous correlations. Since the new correlation is the only one which incor
porates procedures and corrections to reduce the potentially large variability
of the Becker Penetration Test procedures, it seems reasonable to conclude
that it ~s a distinct improvement over those presented previously and can be
used with a good degree of confidence for evaluating the engineering pro
perties of coarse-grained cohesionless soils.
Tab
le
7:
Sum
mar
y o
f D
ata
Use
d to
Dev
elop
Cor
rect
ed B
ecke
r-SP
T B
1ow
coun
t C
orr
ela
tio
n
Dep
th
Cor
rect
ed B
ecke
r B
1ow
coun
t, NB
C C
orre
cted
SPT
B
1ow
coun
t, N6
0 S
ite
(feet)
R
ange
M
ean
Ran
ge
Mea
n
4 -
6 2
.5 -
3.5
3
. 3
. -
4.5
3
.5
7 -
9 3
. -
4.5
3
.5
3.
-4
.5
3.5
10
-
12
3.5
-8
. 5
.5
1.5
-7
.5
5.
13
-15
4
.5 -
8.
6.5
7
.5 -
7.5
6
.5
16
-18
6
. -
13
. 8
. 7
.5 -
16
. 1
1.5
SA
LIN
AS,
CA
19 -
21
9.
-1
6.
12
. 1
1.
-1
3.5
1
2.
22
-24
9
.5 -
23.
15
.5
7.5
-1
3.5
1
1.5
25
-
27
9.5
-26
. 1
8.
6.5
-1
7.5
1
2.5
28
-
30
J4.
-26
. 20
.5
12
. -
15
. 1
4.
31
-33
1
8.
-29
. 2
2.5
1
3.5
-20
. 1
8.
34
-37
1
3.5
-23
. 1
9.5
1
3.5
-2
1.5
1
7.5
11
-12
1
9.
-2
8.
23
.5
9.
-5
4.5
2
6.5
14
-
16
13
. -
36.
26.
15
.5 -
28
.5
22.
18
-19
1
8.
-30
. 2
5.5
1
4.5
-3
8.5
2
4.5
TH
ERM
AL I
TO,
CA
21
-23
25
. -
36
. 3
0.5
1
7.
-2
8.5
22
. 25
-
26
30.
-3
7.
34
.5
20.
-3
8.5
25
. 28
-
29
43.
-5
6.
50.
24
.5 -
70.
36
.5
3 -
5 7
.5 -
9.5
8
. 1
8.5
-1
9.)
1
9.
6 -
7 8
.5 -
8.5
8
.5
11
. -
15
.5
13
. 8
-11
9
.5 -
11
. 10
. 1
1.
-1
2.5
1
1.5
12
8
.5
8.5
7
.5
7.5
13
-
14
8.
-8
.5
8.5
1
. -
1.
1.
SAN
DIE
GO
, CA
15
-
19
13
. -
13
.5
13
. 1
7.5
-25
. 20
. 20
-
25
12
. -
26
.5
18
. 2
4.5
-2
8.5
2
6.5
26
-
31
48.
-6
6.5
57
. 3
6.5
-4
2.5
3
9.5
32
-
38
59
. -
90.
72
.5
39
.5 -
57
.5
50
.5
39 -
44
76.
-9
6.
82
.5
50.
-9
3.
72.
45
-49
74
.5 -
108.
5 10
2.
64.
-103
.5
74
.5
So
il
Type
fviL ML
M
L ML
SM
SP-S
M
SP-S
M
SP-S
M
SP-S
M
SP-.9
1 SP
-SJv
I
SP-S
M
SP-S
M
SP-S
M
SP-S
M
I
SP-S
M
I
SP-S
M
I i
SP-.9
1 I
SP-.9
1 SM
SM
.9
1 SM
SM
SM
SN
.91 SM
I-
' I-
' .p
.
10
- 0 0 -..... 1/1 ~
0 .Q
60
- 0 • Z I- Z
:l
0 U ~
0 ...J
CO
l- n.
V)
0 W
.....
U w
a:
a:
0 u
20
4
0
10
1
0
• ~
SAL
INA
S H
IT
IIT
IE
(SIL
T
• SA
ND
I
• T
HIE
RM
AL
ITO
T
IEST
II
TIE
IIA
ND
I
• SA
N
DIIE
OO
T
IEST
II
TIE
(S
ILT
Y
lAN
D
• IA
ND
I
12
0
CO
RR
EC
TE
D
BE
CK
ER
B
LOW
CO
UN
T, N
BC (
blow
slfo
otl
FIG
. 67
CO
RREL
ATIO
N BE
TWEE
N CO
RREC
TED
BECK
ER A
ND S
PT B
LOW
COUN
TS
14
0
t ....
I-'
V1
REFERENCES
1. Andrus, R. D., Youd, T. L., and Carter, R. R. (1986), "Geotechnical Evaluation of a Liquefaction Induced Lateral Spread, Thousand Springs Valley Idaho", Proceedings of the Twenty-Second Annual Symposium on Engineering Geology and Soils Engineering, Boise, ID, February 24-26, 1984.
2. Becker Drills, Inc., Literature and file data, Denver, Colorado.
116
3. California Department of Water Resources (1983), "Thermalito Afterbay Dam Seismic Evaluation," Final Draft Report and supplemental file data.
4. Coulter, H. W. and Migliaccio, R. R. (1966), "Effects of the Earthquake of March 27, 1964 at Valdez, Alaska," U. S. Geological Survey Professional Paper 542-C, U. S. Department of the Interior.
5. Decker, M. D., Holtz, R. D. and Kovacs, W. D., "Energy Transfer of SPT Hammers," in preparation.
6. Ertec Western, Inc. (1981) "Evaluation of the Cone Penetrometer for Liquefaction Hazard Assessment," Report to the U.S. Geological Survey.
7. Ertec Western, Inc. (1984), "Cone Penetrometer Test: Pore Pressure Measurements and SPT Hammer Energy Calibration for Liquefaction Hazard Assessment," Report to the u.s. Geological Survey.
8. Fuller, Frank M. (1983), Engineering of Pile Installations, McGraw-Hill, Inc., New York.
9. Geotechnical Consultants, Inc. (1981), "Geotechnical Evaluation of Alluvium, Santa Felicia Dam, Ventura County, California," Report to the United Water Conservation District, October.
10. Geotechnical Consultants, Inc. (1983), "Geotechnical Investigation for Vern Freeman Diversion Structure, Santa Clara River near Saticoy, Ventura County, California," Report to the United Water Conservation District, November.
11. Harder, Jr., Leslie F. (1986), "Use of Penetration Tests to Determine the Liquefaction Potential of Soils During Earthquake Shaking," Dissertation submitted in partial fulfillment for Doctor of Philosophy Degree, University of California, Berkeley, (In preparation).
12. Harder, Jr., Leslie F. (1986), "Evaluation of Becker Penetration Tests Performed at the Mormon Island Dike, Folsom Dam," Report prepared for the Waterways Experiment Station, U.S. Army Corps of Engineers (In preparation) .
13. International Construction Equipment, Inc., Calibration charts for diesel hammer energies.
117
14. Ishihara, Kenji (1985), "Stability of Natural Deposits During Earthquakes," Proceedings of the Eleventh International Conference on Soil Mechanics and Foundation Engineering, San Francisco, California, 1985.
15. Jones, Walter V. and Christensen, Curt (1982), "Performance of HeavilyLoaded Shallow Foundations Supported on Gravels," Paper presented at the 1982 ASCE National Convention, New Orleans, Louisiana, October 25-29, 1982.
16. Last, Tony (1985), International Construction Equipment, Inc., Personal c ormnuni cat ion.
17. Liang, Nancy (1983), "An Examination of the Standard Penetration Test with Comparisons to Other In Situ Tests," Senior Thesis, University of British Columbia, April.
18. Mitchell, James K. (1986), "Practical Problems From Surprising Soil Behavior," The Twentieth Karl Terzaghi Lecture, Journal of the Geotechnical Engineering Division, ASCE, Vol. 112, No.3, March.
19. Northern Engineering and Testing, Inc., File data for Job Nos. 68-16, 68-17, 68-19, and 68-204.
20. Peck, Ralph, Hanson, W. E., and Thornburn, T. H. (1974), Foundation Engineering, Second Edition, Wiley, New York.
21. Rempe, D. M. and Davisson, M. T. (1977), "Performance of Diesel Pile Harmners," Proceedings of the Ninth International Conference of Soil Mechanics and Foundation Engineering, Tokyo, Japan, 1977.
22. Seed, H. Bolton, Tokimatsu, K., Harder, L. F., and Chung, Riley M. (1985), "Influence of SPT Procedures in Soil Liquefaction Resistance Evaluations," Journal of the Geotechnical Engineering Division, ASCE, Vol. 111, No. 12, December.
23. Sergent, Hauskings and Beckwi th (1973), "An Inves tigation of the Load Carrying Capacity of Drilled Cast-In-Place Concrete Piles Bearing On Coarse Granular Soils and Cemented Alluvial Fan Deposits," Report to the Arizona Highway Department, Phoenix, Arizona.
24. Terzaghi, K. (1943), Theoretical Soil Mechanics, John Wiley and Sons, New York.
25. Wang, Wenshao (1984), IIEarthquake Damages to Earth Dams and Levees ~n Relation to Soil Liquefaction,1I Proceedings of the International Conference on Case Histories in Geotechnical Engineering, 1984.
26. Youd, T. L., Harp, E. L., Keefer, D. K., and Wilson, R. C. (1985), liThe Borah Peak, Idaho Earthquake of October 28, 1983--liquefaction,1I Earthquake Spectra, Earthquake Engineering Research Institute, Vol. 2, No.1, November.
General
APPENDIX
DERIVATIONS OF RELATIONSHIPS BETWEEN DIESEL HAMMER ENERGY AND BOUNCE CHAMBER PRESSURE
118
This appendix presents the derivations of potential energy stored in the
bounce chamber, total potential energy, and kinetic energy of ram impact. The
derived energies are correlated to the peak pressure measured in the bounce
chamber and are based on the laws of thermodynamics. The derived equations
for potential energies were used by International Construction Equipment, Inc.
(ICE) to produce the energy correlation charts shown in Figure 29b. Details
of the derivations were provided by Tony Last, ICE representative.
Derivation of Potential Energy Stored in Bounce Chamber
A diesel pile hammer is basically a single cylinder diesel engine. For
the ICE Model 180, the top of the cylinder is closed off and, during the up-
ward travel of the ram, air is trapped above the ram in the upper half of the
cylinder (compression cylinder) and in an adjoining bounce chamber. This
trapped air is compressed by the ram and acts as a spring on the ram. Much of
the potential energy of the ram comes from the stroke energy (ram weight times
stroke distance). However, the trapped air above the ram also provides a
substantial portion of the potential energy.
To calculate the potential energy stored Ln the compressed aLr above the
ram, the following gas law for polytropic expansion and compression was used:
pvn = constant (A.1)
where P = absolute pressure
v = volume
n = exponent
119
Shown in Figure A.I is a curve which represents the application of this
pressure-volume relationship during the upstroke of the ram. Just as the ram
closes the atmospheric ports of the compression cylinder on its upstroke, the
initial absolute pressure, PI' is equal to atmospheric pressure. The volume
of air above the ram in the compression cylinder and bounce chamber at
atmospheric port closure is denoted as VI. For the ICE Model 180 ha~~er, this
volume is equal to 6773 cubic inches. As the ram continues upward, the volume
of air LS compressed and the pressure is increased. At the top of the stroke,
the trapped volume reaches a minimum value ot V2
and the compressed aLr
pressure reaches a maximum value of P2
. Using appropriate fittings and a
gage, this peak pressure, P2
, can be monitored during driving and is denoted
as the bounce chamber pressure.
During the downstroke of the ram, potential energy in the trapped air
performs work on the ram by expanding back along the curve shown in Figure A.I
until the initial conditions are restored. The increment of work is
represented by:
Increment of work = F • ds = P • A • ds = P • dv (A.2)
where F = Force acting on ram
A = Ram area
P = Pressure acting on ram
dS = Increment of ram travel along the cylinder
dV = Increment of volume change in the cylinder
The total gross work performed on the ram by the expansion of the trapped air,
ignoring mechanical friction, then becomes:
VI
Total gross work, EC =~ p. dV (A.3)
V2
•
w Pz - - __ a:: ::> en en w a:: a.. w .-::> ....J o en CD <t
dV
VOLUME
= CONSTANT
PI = Initial absolute pressure above ram in compression cylinder and bounce chamber oefore ram oegins its upstroke.
= aosol ute atmospheric pressure.
P2 = Peak absolute pressure above ram in compression cylinder and bounce chamber at top of ram stroke. Measured Oy pressure gage.
VI = Total trapped air volume above ram in compression cylinder and bounce chamber at atmospheric vent closure.
= 6773 cu. in. for ICE Model 180 diesel hammer.
V2 = Volume of compressea air above ram in compression cylinder and bounce chamber at top of ram stroke .
. n = Exponent = 1.4 for adiabatic conditions.
FIG. A.l PRESSURE-VOLUME RELATIONSHIP USED FOR DERIVING POTENTIAL ENERGY STORED IN BOUNCE CHAMBER
120
121
This total gross work is equivalent to the area beneath the curve shown in
Figure A.I. To solve the above equation, it should be noted, from Equation
n A.I, that PV = constant and therefore:
PVn = constant
and n
p P1V1
= Vn
~/1 =/1 n /1 P • dV P1V1 dV P1v1
n V-n dV EC Vn
V2 V2
V2
Thus
= 1 - n
= (A.4)
To obtain the useful work, EBC ' stored in the compression cylinder and
bounce chamber, one must subtract the work performed by the atmosphere on the
ram, EA' This work LS represented by the cross-hatched area shown in Figure
Thus, the useful work that is stored Ln the compression cylinder and
bounce chamber becomes:
(A.5)
In this equation, parameters PI and VI are known quantities before the test
and P2 is simply the pressure measured in the bounce chamber. The parameter,
V2 ' is calculated using equation A.l:
122
(A.6)
The value of the exponent, n, is equal to 1.4 for the adiabatic (no heat
transfer) compression and expansion of air. Although the action within the
compression cylinder is not strictly adiabatic because of the potential for
heat transfer between the air and the metallic surfaces of the cylinder and
ram, the cycle is so rapid that little time exists for heat transfer and the
process approaches adiabatic conditions. Thus, for volumes expressed in cubic
inches, pressures in psia, and energy expressed in ft-lb., equation A.S
becomes:
EBC
P1
V1 - P2V
2 PI (V 1 - V 2)
12(1 - 1.4) 12
P2
V2
- P1
Vl Pl (V1
- V2) (A. 7) = 4.B 12
Calculation of Total Potential Energy
As previously described, the total potential energy is composed of (1)
the energy stored in the a1r compressed above the ram, EBC ' and (2) the stroke
energy, EWH
, of the ram. To obtain the stroke energy, it is necessary to
determine the product of the weight of the ram and the maximum upward travel
or stroke of the ram. For the ICE Model lBO, the ram weighs 1724 pounds. To
determine the stroke of the ram, the volume change of the air trapped above
the ram is simply divided by the area of the ram. For the ICE Model 180, the
area of the ram is 95.0 square inches.
Compression Cylinder Ram Stroke
Thus:
Volume Change of Trapped Air Ram Area
Vl - Vz cu. in.
95.0 sq. in. (A.8)
123
Because the ram does not close off the atmospheric ports in the upper cylinder
until after 1 inch of upward travel after striking the anvil, the total ram
stroke equals the stroke calculated from the compression cylinder volume o
change plus 1 inch. Thus:
(VI - V2) cu. in. Total Ram Stroke, H = 95 0 . + 1 inch • sq. In.
The stroke energy of the ram then becomes:
W H = 1724 lb. 12 . [ (VI - V2) cu. in.
95.0 sq. in. + 1 inCh] ft.-lb.
(A.9)
(A.10)
The total potential energy values calculated by ICE for their energy vs.
bounce chamber curves (Figure 29b) are the sum of EBC
and EWH . To demonstrate
the use of the above equations, an example 1S shown in Figure A.2 for the case
where an ICE Model 180 hammer is operating at sea level and a bounce pressure
reading of 20 psig is recorded. For such a case the total potential energy of
the ram, EpE ' is 6804 ft-Ib.
Impact Kinetic Energy
The above calculations show how the total potential energy of the ram is
determined. However, not all of this potential energy is converted into the
kinetic energy of the falling ram. As the ram falls towards the anvil and
compresses the fuel-air mixture in the combustion chamber, some of the
potential energy is lost as a result of the work required to compress the
fuel-air mixture. The magnitude of this lost work can be calculated using
equation A.7:
Work Done in Compression =
EXAMPLE: ICE Model 180 Diesel Pile Hammer Operating at Sea Level
Bounce Chamber Pressure = 20 psig
PI = 14.7 psia
VI = 6773 cu. in.
P2
= 20 psig + 14.7
Equation A.6 V2 = 1.4 V 1.4
1 1 P2
psi = 34.7 psia
1 4~14.7)(6773)1.4 • 34.7
Potential Energy Stored in Bounce Chamber:
Equation A:7 EBC
3667 cu. in.
124
= .=...34.;.....:...;.7...",(.;:,..36:....;6'-'-7-'-:) _--='1'-'-4...:..... 7'-'-(~6...:....7.;....7 3:....<-) 4.8
_1...;...4 .;.....7--'(...;;..6.;....77--:3:-----"-36:....:6;.....7..:-) = 12 1962 ft.-lb.
Maximum Stroke of Ram:
Equation A.9 H VI - V2 --'---- + 1 inch = Ram Area
Potential Stroke of Ram:
(6773 - 3667)cu. in. + 1 inch = 33.7 in. 95.0 sq. in.
Equation A.lO l\m == WxH 1724 lb ·33.7 in./12 in./ft. = 4842 ft.-lb.
Total Potential Energy of Ram
Total Potential Energy == Bounce Chamber Potential Energy + Ram 'Stroke Potential Energy
EpE = 1962 + 4842 ft. lb.
EpE == 6804 ft. lb.
FIG. A.2 EXAMPLE CALCULATION OF POTENTIAL ENERGY OF DIESEL PILE HAMMER RM1
where
125
PI = Absolute atmospheric pressure (psia)
VI = Volume of air trapped beneath the ram after the ram closes
the intake and exhaust ports 1n the lower cylinder (for ICE
Model lBO, VI = 777 cu. in. )
V2 = Volume of air trapped in the combustion chamber
strikes the anvil (for ICE Model
P = Absolute compression pressure = 2
as the ram
cu. in.)
For sea level conditions:
Thus:
. (777 )1.4 14.7 pS1a 51
= (666) (51) - 14.7 (777)
4.B
= 3807 ft-1b.
= 666 psia
14.7(777 - 51) 12
This work performed in the compreSS10n of the fuel-air mixture is energy
lost from the total potential energy of the ram. Thus the amount of energy
available as kinetic energy at ram impact is significantly reduced. It should
be noted that this compression energy loss is a constant regardless of the
bounce chamber pressure and depends only on the atmospheric pressure. Thus,
the proportion of the potential energy available as kinetic energy is greatly
reduced as the bounce chamber pressures, and therefore the potential energies,
become lower. For example, a bounce chamber pressure of 20 psig recorded at
sea level yields a total potential energy of 6804 ft-lb. By subtracting the
compression energy loss (3807 ft-lb.), the impact kinetic energy becomes 2994
ft-lb. However, a bounce chamber pressure of 15 psig recorded at sea ~evel
yields a total potential energy of about 5530 ft-lb. and an impact kinetic
energy of about 1720 ft-lb. In general:
Impact Kinetic Energy = Total Potential Energy - Compression Loss
or
Thus:
126
for (BP)SL = 20 psig, Impact Kinetic Energy = 6804 - 3907 = 2997 ft-lb
for (BP)SL = 15 psig, Impact Kinetic Energy = 5530 - 3807 = 1723 ft-lb
Thus the Impact Kinetic Energy is significantly less than the Potential
Energy and this difference must be considered ~n evaluating the effective
energy determining the penetration resistance of the casing.
EARTHQUAKE ENGINEERING RESEARCH CENTER REPORTS
NOTf: Numtlers in parentheses are Access ion Numbers assigned by the Na tional Technical Information Serv icc; the se ilre follow~d by a price code. Copies of the reports may be ordered from the National Technical Information Service, 5285 Port Royal Road, Springfield, Virginia, 22161. Accession Numbers should be quoted on orders for reports (PB --- ---I and remittance must accompany each order. Reports without this information were not available at time of printing. The complete list of EERC reports (from EERC 67-1) is available upon request from the Earthquake Engineering Research Center, University of California, Berkeley, 47th Street and Hoffman Boulevard, Richmond, California 94804.
UCD/H:RC-79/0i "lIysteretic Behavior of Lightweight ~einforced Ooncrete Beam-Column Subassembiages," by B. forzani, E.P. Popov and V.V. Bertero - Ap~il 1979(PB 298 267)A06
UCil/J:J":IIC-79/02 "The Development of II Mathematical ~del to Predict the Flexural Response of Reinforced Concrete Beams to Cyclic Loads, Using System Identification," by J. Stanton & H. McNiven - Jan. 1979(PB 295 875)"10
UCR/EFnC-79/0] "Linear and Nonlinear Earthquake Response of Simple Torsionally Ooupled Systems," by C.L. Kan and A.K, Chopra - Feb. 1979(PB 298 262)A06
UCB/EERC-79/04 "A Mathematical ~del of Masonry for Predicting its Linear Seismic Response Claracteristics," by Y. Mengi and H.D. McNiven - Feb. 1979(PB 298 266)A06
UCB/r:F.RC-79/05 "Mechanical Behavior of Lightweight Concrete Confined by Different Types of Lateral Reinforcement," by M.A. Manrique, V.V. Bertero and E.P. Popov - May 1979(PB 301 114)A06
UCB/F:I:RC-79/06 "Static Tilt Tests of a Tall Cylindrical Liquid Storage Tank," by R.W. Clough and A. Niwa - F'eb. 1979 (PB 301 167)1\06
UCB/E:ERC-79/07 "The Design of Steel Energy Absorbing Restrainers and !lIeir Incorporation into Nuclear Po·.rer Plants for Enhanced Safety: Volume 1 - SW11I1ary Report," by P.N. Spencer, V.F. zackay, and E.R. Parker-Feb. 1979(UCB/EERC-79/07)A09 "
UOl/Ef:RC-79/08 "The Design of Steel Energy Absorbing Restrainers and Their Incorporation into Nuclear Power plants for Enhanced Safety: Volume 2 - The Development of Analyses for Reactor System Piping, ""Simple Systems" by M.C. Lee, J. Penzien, A.K. Clopra and K, Suzuki "Complex Systems" by G.H. PowelL E.t-. Wilson, R.W. Clough and D.G. Row - Feb. 1979(UCB/EERC-79/08)A10
UCIl/r::r::RC-79/09 '''r1te Design of Steel Energy Absorbing Restrainers and Their Incorporation into Nuclear Power Plants for Enhanced Safety: Volume ]- Evaluation of Commercial Steels," by W.S. o,.,en, R.M.tl. Pelloux, R.O. Ritchie, M. Faral, T. Ohhashi, J. Toplosky, S.J. Hartman, V.F. Zackay and E.R. Parker -Feb. 1979(UCB/EERC-79/09)A04
UCB/FT:I,C- 79/10 "The Design 0 f Steel En"ergy Absorbing Res trai ners and Their Inco rporation in to Nuc lear Power Plan ts for EnJ.anced Sa fety: Vol ume 4 - A Review of Energy-Absorbing Devices," by J. M. Kelly and M.S. Skinner - feb. 1979(UCB/EERC-79/10)A04
UCil/[THC-79/11 "Conservatism In Summation Rules for Closely Spaced MOdes," by J.M. Kelly and J.L. Sackmiln - May 1979 (PB 301 328) AO)
UCB/fF.I<C-79/l2 "cyclic Loading Tests of Masonry Single Piers; Volume] - Height to Width Ratio of 0.5," by P.A. Hidalgo, R.L. Mayes, H.D. McNiven and R.W. Clough - May 1979(PB 301 ]21)A08
UCB/Ef.fIC- 79/lJ "Cyclic Behavior of Dense Oourse-Grained Materials in Relation to the Seismic StaJ:>ility of Dams," by N.G. Banerjee, H.B. Seed and C.K. Chan - June 1979(PB 301 )7])AIJ
UCB/Ef.RC-79/l4 "Seismic Behavior of Reinforced Ooncrete Interior Beam-Column Subassemblages," by S. Viwathanatepa, E.P. Popov and V.V. Bertero - June 1979(PB ]01 326)AIO
UCB/Ef~r.C-79/l5 "Optimal Des ign of Locali zed Nonlinear systems wi th Dual Per formance Cri teria Under Earthquake Excitations," by M.A. Bhatti - July 1979(PB 80 167 109)A06
UCil/E:J';RC-79/16 "OPTDYN - A General Purpose Optimization Proqram for Problems with or wi thout Dynamic Constraints ," by M.A. Bhatti, E. polak and K.S. Pister - July 1979(PB 80 167 091)A05
UCIl/f:J-:HC-7Cl/17 "A NSR-II, Analysis of NOnlinear Structural Response, Users Manual," by D.P. ~ndkar and G.H. Powell July 1979 (PB 80 113 30l)A05
UCD/Frr~r-7'l/tA "Soil Structure Interaction in Di fferent Seismic Environments," A. Gomez-Masso, J. Lysmer, J .-C. Chen and H.B. Seed - August 1979(PB 80 101 520)A04
UCR/EERC-79/19 "ARMA /'tldels for Earthquake Ground Motions," by M.K. Clang, J.W. Kwiatkowski, R.F. Nau, ~.M. Oliver and K.S. Pister - July 1979(P8 301 l66)A05
UCB/f:r:HC- 79/20 "Hys teretic Behavior 0 f Rein fo rced Concrete S tructura1 Walls," by J. M. Vallenas, V. V. Be rtero and E.P. Popov - August 1979(PB 80 165 905)1112
UCB/F.:F1!C-79/2l "Studies on High-Frequency Vibrations of Buildings - 1; !lie Oolumn Effect," by J. Lubliner - August 1979 (PB 80 158 5S3)AO]
UCB/Ef.HC-79/22 "Effects of Generalized Loadings on Bond Reinforcing Bars Embedded in Confined Concrete BloCks," by S. Viwathanatepa, E.P. Popov and V.V. Bertero - August 1979(P8 81 124 018)A14
UCD/EE:PC-7'l/23 "Shaking Tabl e Study 0 f Single-S tory Masonry Houses, Volume 1 : Test Structures 1 and 2, " by P. Gulkan, R.L. Mayes and R.W. Clough - Sept. 1979 (HUD-OOO l76])A12
UCB/E:f.HC-79/24 "Shaking Table Study of "Single-Story Masonry Houses. Volume 2: Test Structures 3 and 4, " by P. Gulkan, R. L. Mayes and R.W. Clough - Sept. 1979 (HUD-OOO 1836)A12
UCB/Ef.RC-79/25 '·Shalling Table Study of Single-Story Masonry Houses, Volume 3: Summary, Oonciusions and Recommendations," by R.W. Clough, R.L. Mayes and P. Gulkan - Sept. 1979 (HUD-OOO 1837)A06
uOI.:n:HC-N/26 "Reo:"nmen<Jations tor a U.S.-Japan Cooperative Research Program Ut1lizing Large-Scaif! Testing f'"ci li tic,,, ," by U.S.-Japan Planning Group - Sept. 1979(PB 301 407)A06
UCI'," t-:f:RC-7'l/2 7 "Earthquake - Induced Lique faction Nea r Lake Arnati tlan, Gua temala," by II. B. Seed, I. IIranqo, C. K. (:han, A. Gomez-Masso and R. Grant de Ascoli - Sept. 1979(NUREG-CRl341)1I03
u('n/F:f::"C-7~/2f1 "lnHll Panels: 'Their Influence on Seismic Response of Buildings," by J.W. IIx1ey and V.V. Bertero Sept. 1979(PB BO 16.1 371) AlO
UrH/CU<C-7':1/29 "3D Truss Bar Element (Type 1) for the ANSR-II Program," by D.P. to'ondkar and G.H. Powell - Nov. 1979 (PR 80 169 709)1102
UCiI/EERC-79/30 "20 Beam-Column Element (Type 5 - Parallel Element 'Theory) for the ANSR-II Program, " by D.G. Row, G.H. Powell and D.P. to'ondkar - Dec. 1979(PB BO 167 224) 1\03
U(11/F.F.!c.- 79131 "3D Beam-Column Element (Type 2 - Parall e1 Element 'Theory) for the IINSR- I I Progrilm," by II. Riahi, G.I!. Powell and D.P. to'ondkar - Dec. 1979(PB BO 167 216) 1103
u('n/EFI~c-79/32 "On Response of Structures to Stationary Excitation,· by A. Der Kiureghian - Dec. 1979(PB 8r) 16(929)1103
UCH,'CF.RC-79/33 "Undisturbed Sampling and Cyclic Load Testing of Sands," by S. Singh, H.B. Seed and C.K. Ch,ln Dec. 1979(1\011 DB7 29B)A07
UC'T1/EEHC-791J4 "Interaction Effects of Simul taneous Torsional and Compressional Cyclic Loading 0 f Sand," by P.M. r.riffin and W.N. Houston - Dec. 1979(ADA 092 352)1115
UC(I,F.EHC-AO/Ol "Earthquake Response of Concrete Gravity Dams Including Hydrodynamic and foundation Interilction Effects," by A.K. Chopra, P. Chakrabarti and S. Gupta - Jan. 19BO(AD-AOA7297)A\O
IlCI!/I:.'I:I'C-BD/02 "Rocking Response of Rigid Blocks to Earthquakes," by C.S. 'lim, II.K. Chopra and J. Penzien - Jan. l':1HO (PBAO 166 (02)11(14
UC'IJ/I-:t:RC-flO/'J3 "Optimum Inelastic Design of Seismic-Resistant Reinforced Concrete Frame Structures," by S.W. Zagajeski and V.V. Bertero' - Jan. 19BO(PB80 164 635)1106
U(,II/Et:kC-80/04 "Effects of Amount and Arrangement of Wall-Panel Reinforcement on Hysteretic Behavior of Reinforced Concrete Walls," by R. Iliya and V.V. Bertero - Feb. 19BO(PBBI 122 525)~09
UClJ/f.F:HC-BO/OS "Shaking Table Research on Concrete Dam Models," by ~. Niwa and R.W. Clough - Sept. 1980(PB81122 36B),vJ6
UCI','t:I:RC-80/06 "The Design of Steel Energy-Absorbing Restrainers and their Incorporation into Nuclear Pm,er Plallts for Enhanced Safety (Vol lAl: Piping with Energy Absorbing Restrainers: Parameter Study on Small Systems," by G.Il. Powell, C. Oughourlian and J. Simons - June 1980
UCB/EERC-BO/07 "Inelastic Torsional Response of Structures Subjected to Earthquake Ground Motions," by Y. Yamazaki April 19BO(PBBl 122 327)AOB
ucr/EERC-B%a "Study of X-Braced Steel frame Structures Under Earthquake Simulation," by 'l. Ghanaat - April 19Br) (PBBl 122 335)All
[J(:n/i:f:f,C-BO/09 "Hybrid Modelling of Soil-Structure Interaction," by S. Gupta, T. W. Lin, J. Penzien and C. S. Yeh May 19BO(PBBl 122 319)A07
UCn/EEIlC-BO/lO "General Applicability of a Nonlinear Model of a One Story Steel Frame," by B.1. Sveinsson and H.D. McNiven - !'lay 19BO(PBBl 124 877)1106
UCB/EEkC-BO/ll "A Green-Function Method for Wave Interaction with a Submerged Body," by W. Kioka - April 19BO (PBBI 122 269)A07
lICfl/f.f.I<C-BO/12 "Hydrodynamic Pressure and Added tlass for Axisynunetric Bodies," by F. Nilrat - May 1980 (PBBI 122 343) AOf:!
UCB/F.f.RC-BO/13 "Treatment of Non-Linear Drag f'orces IIcting on Offshore Platforms," by B.V. Dao and J. Penzien May 19BO(PBBl 153 413)1107
UCB/f.ER~-BO/14 "20 Plane/Axisymmetric Solid Element (Type 3 - Elastic or Elastic-Perfectly Plastic) for the IINSR-II Program," by D.P. Mondkar and G.H. Powell - July 19BO(PBBl 122 350)A03
UCB/Ef.RC-BO/15 "~Response Spectrum Method for Random Vibrations," by ~. Der Kiureghian - June' 1980(PBBl 122 301)~03
UCIlI \,;EHC-BO/16 "Cyclic Inelastic Buckling of Tubular Steel Braces," by V.A. Zayas, E.P. Popov and S.A. r1ailin June 19BO(PBBl 124 BB5)1I10
UCA/EERC-BO/17 "Dynamic Response of Simple ~rch Dams Including Hydrodynamic Interaction," by C.S. Porter and A.K. Chopra - July 19BO(PBBl 124 000)A13
L'CB/EERC-BO/IB "Experimental Testing of a Friction Damped Aseismic Base Isolation System with Fail-Safe Characteristics," by J.M. Kelly, K.E. Beucke and M.S. Skinner - July 19BO(PBBl 14B 595)1104
UCB/f.ERC-BO/19 "The Design of Steel Energy-Absorbing Restrainers and their Incorporation into Nuclear Power Plants for Enhanced Safety (Vol IB): Stochastic Seismic Analyses of Nuclear Power Plant Structures and Piping Systems Subjected to Multiple SUPpOrt EXCitations," by M.C. Lee and J. Penzien - June 19BO
UCD/EEI<C-BO/20 "The Design of Steel Energy-Absorbing Restriliners and th .. ir Incorporation Intn Nuc\eilr Power Plants for Enhanced Safety (Vol lC): Numerical Method for Dynamic Substructure AnalYSis," by J.M. Dickf!ns and E.L. Wilson - June 19BO
UCB/E~:RC-BO/21 "The Design of Steel Energy-Absorbing Restrainers and their Incorporation into Nuclear Power Plants for Enhanced Safety (Vol 2): Development and Testing of Restraints for Nuclear Piping Systems," by J.M. Kelly and M.S. Skinner - June 19BO
UCB/t:ERC-BO/22 "3D Solid Element (Type 4-Elastic or Elastic-perfectly-Plastic) for the IINSR-II Program," by D.P. Mondkar and G.H. Powell - July 1980(PBBl 12] 242)A03
UCB/r.ERC-BO/23 "Gap-Friction Element (Type 5) for the ANSR-II program," by D.P. Mondkar and G.H. Powell - July 19BO (PBBl 122 2B5)AO]
;.:69
UCfl/I-:i:I(l'-HO(24 "U-Bar ~estraint Element (Type 11) for the ANSR-II Program," by C. Ougilourliall and G.H. Powell July 19BOIPBBl 122 29))AOJ
UCfI/ITI,('-HO(25 "Tc~ting of a Natural Rubber Base Isolation System by an Explosively Simulated Earth'!llakE'," 1,,'1 J.M. Kelly - August 19BOIPBBl 201 )60)"04
UCB/r~Rr-RO(26 "Input Identification from Structural Vibrational Response," by Y. Hu - August 1980(PB81 152 308)"05
U~O/~I:rn'-80(27 "Cyclic Inelastic Behavior of Steel Offshore Structures," by V.A. Zayas, S.A. Mahin and E.P. Popov August 19BOIPS81 196 18o)A15
UC1\/fTIW-i:l0/2B "Shakinq T.J.ble Testing of a Reinforced Concrete Frame with BiaKial Response," by M.G. Oliva October 19BO(PB81 154 )04)A10
UCB/EEilC-BO/29 "Dynamic Properties of a Twelve-Story Prefabricated Panel Building," by J .G. Bouwkamp, J.P. and R.M. Stephen - October 1980(PBB2 117 128)AOG
L1CB/I:I:HC-AO/ )0 "Dynamic Properties of an Eight-Story Prefabricated Panel Building, " by J.G. Bouwkamp, J.P. and R.M. Stephen - October 1980(PB81 200 313) 1105
I<Dllegger
Kollegger
UCB/Ef.RC-BO/31 "Predictive Dynamic Response of Panel Type Structures Under Earthquakes," by J.P. Kullegger and J.G. Bouwkamp - October 1980(PS8l 152 316)1104
UCS/Er.RC-BO/32 "The Design of Steel Energy-Absorbing Restrainers and their Incorporation into Nuclear Power Plants for Enhanced Safety (Vol 3): Testing of Commercial Steels in Low-Cycle Torsional Fatigue," by P. ~r~~r~r, E.R. Parker, E. Jongewaard and M. Orory
UCI\i!:.I'_kC-~0/33 "Tht! 1J,,~igll of Steel Energy-Absorbing Restrainers and their Incorporation into Nuciear FO"'''t Plants for Enhanced Safety (Vol 4): Shaking Table Tests of piping Systems with Energy-llbsorbing Restrainers," by S.F. Stiemer and w.G. Godden - Sept. 19BO
UCfl/FI:RC-\l0/34 "The Design of Steel Energy-Absorbing Restrainers and their Incorporation into Nuclear Power Plants for Enhanced Safety (Vol 5): Summary Report," by P. Spencer
UC3/FERC-A0/35 "experimental Testing of an Energy-Absorbing Base Isolation System," by J.M. Kelly, 11.S. Sl<inner and K.E. Beucke - October 19BO(PB81 154 072)A04
UCB/Er.RC-BO/36 "Simulating and Analyzing Artificial Non-Stationary Earthquake Ground Motions," by R.r. Nau, R.M. Oliver and K.S. Pister - October 1980(PB8l 153 397)A04
UCB/I:~:I'C-flo/37 "Earthquake Engineering at Berkeley - 1980." - Sept. 1980(PB1:!1 205 1374) A09
UCB/[:I:RC-80/3B "Ina las tic Seismic Ana 1ys is of Large Panel Buildings," by V. Schricker ann G. H. Powe 11 - Sept. 19\10 (PBBI 154 33B)A1)
UCIl/ITI<C-A0/39 "Oynamic Response of Embankment, Concrete-Gravity and IIrch Dams Including Hydrodynamic Interaction," by J.F. Hall and A.K. Chopra - October 1980(PB81 152 324)1111
UCB/n:Hc-80/40 "Inelastic Buckling of Steel Struts Under cyclic Load Reversal," by R.G. Black, W.A. Wenger and E.P. Popov - October 1980(PB81 154 312)A08
L1CI1/I'f:P.C-AO/41 "Influence 0 f Si te Characteristics on Building Damage During the October ), 1974 Lima Earth4uilke," by P. Repetto, I. Arango and H.B. Seed - Sept. 19BO(PB81 161 739)A05
UCB/l:EIlC-BO/42 "Evaluation of a Shaking Table Test Program on Response Behavior of a Two Story Reinforced Concrete Frame," by J.M. Slondet, R.W. Clough and S.A. Mahin
UCIl/EEHC-aO/43 "~Iodelling of Soil-Structure Interaction by Finite and Infinite Elements," by f'. Medina -December 1980(PB81 2~9 270)A04
UCB/rXRC-81/01 "Control of Seismic Response of Piping Systems and Other Structures by Base Isolation," edited by J .M. Kelly - January 1981 (PBBl 200 735)A05
UCB/EERC-B1j02 "OPTNSR - An Interactive Software System for Optimal Design of Statically and Dynamically Loaded Structures with Nonlinear Response," by M.A. Bhatti, V. Ciampi and K.S. Pister - January ]981 (PBBl 21B B51lA09
UCfl/I:I,:nC-B1/03 "Analysis of Local Variations in Free Field Seismic Ground Motions," by J.-C. Chen, J. Lysmer and II.B. Seed - January 1981 (AD-A09950B)Al3
UCB/CERC-8l(04 "InelastiC Structural Modeling of Braced Offshore Platforms for Seismic Loading," by V.A. Zayas, P.-S.B. Shing, S.A. Mahin and E.P. Popov - January 1981(PB82 138 777)~07
UCB(EERC-81/05 "Oynamic Response of Light Equipment in Structures," by II. Der Kiureghian, J.L. Sackman and B. NourOmid - April 1981 (PBBl 21B 497)A04
UCB/CEPC-SI/06 "Preliminary Experimental Investigation of a Broad Base Liquid Storage Tank," by J .G. Bouwkamp, J. P. Kollegger and R.M. Stephen - May 1981(PB82 140 385)AO)
UCB/r.ERC-Bl/07 "The Seismic Resistant Design of Reinforced Concrete Coupled Structural Walls," by A.E. Aktan and V.V. Bertero - June 1981(PBB2 113 358)All
L1CB/r:ERe-Bl/OB "The Undrained Shearing Resistance of Cohesive Soils at Large Deformations," by H. R. P· .. l"~ and H. B. Seed - August 19B1
UCB/f.ERC-Bl(09 "Experimental Behavior of a Spatial Piping System with Steel Energy Absorbers Subjected to a Simulated Differential Seismic Input," by S.F. Stiemer, W.G. Godden and J.M. Kelly - July 19B1
UCU/EERC-BI/I0 "EvalUoltion ot SeismJ.c Design Providons tor Masonry in the United States," by B.I. Sveinsson, H.L. Hayes and H.D. McNiven - August 19B1 (PBB2 166 07sl~08
UCD/EERc-el/11 "Two-Dimensional Hybrid Modelling of Soil-Structure Interaction," by T.-J. Tzong, S. Cupta and J. Penzien - August 1981(PBe2 142 lle)A04
UCB/EERC-81/12 "Studies on Effects of Infills in seismic Reaistant RIC Construction," by S. Brokken and V.V. Bertero -September 1981 (FBe2 166 190)A09
UCD/EERC-81/1l "Linear Hodels to Predict the Nonlinear Seismic Behavior of a One-Story Steel Frame," by II. ValdUnarsson, A.H. Shah and H.D. McNiven - Septe~er 19B1(PB82 138 79l)A07
UCB/EERC-81/14 "TLUSIII A Computer Proqram for the Three-Dimensiona 1 Dynamic Ana I ysis a f Earth Dams," by T. Kaqa""a, L.H. Mejia, H.B. Seed and J. Lysmer - September 1981(PB82 139 940)A06
UCB/EEHC-81/1S "Three Dimensional Dynamic Response Analysis of Earth Dams," by L.II. Mejia and H.B. Seed - September 1381 (PBe2 137 274)A12
UCB/EERC-8l/16 "Experimental Study of Lead and Elastomeric Dampers for Base Isolation Systems," by J.M. Kelly and S.B. lIodder - October 1981 (PB82 166 182)AOS
UCB/EERC-81/17 "The Influence at Base Isolation on the Seismic Response of Liqht Secondary Equipment," by J.M. r~lly -April 1981 (PBB2 255 266)A04
UCB/EERC-Bl/18 "StudIes on Evaluation of Shaking Table Response Analysis Procedures," by J. Marcial Blondet - November 1981 (PBB2 197 278)AlO
UCB/EERC-81/19 "DELIGHT.STRUCT: A Computer-Aided Design Environment for Structural Engineering," by R.J. Ballinq, K.S. Pister and E. Polak - December 1981 (PB82 218 4961A07
UCB/EERC-8l/20 "Optimai Design of SeismiC-Resistant Planar Steel Frames," by R.J. Balling, V. Clampi, K.S. pister and E. Polak - December 1981 (PB82 220 1791A07
UCB/EERC-82/01 "Dynamic Behavior of Ground for Seismic Analysis of Lifeline Systems," by T. Sato and A. Der Kiureqhian -January 1982 (PB82 218 9261A05
UCB/EERC-B2/02 "Shaking Table Tests of a TUbular Steel Frame HodeL," by Y. Ghanaat and R. W. CLough - January 198. (PBB2 220 161)A07
UCB/EERC-B2/0l "Behavior of a Piping System under Seismic Excitation: Experimental Investigations of a spatial Piping system supported by Mechanical Shock Arrestors and Steel Energy Absorbing Devices under Seismic Excitation," by S. schneider, H.-H. Lee and W. G. Godden - Hay 1982 (PB8l 172 S44)A09
UCB/EERC-82/04 "New Approaches for the Dynamic Analysis of Large Structural Systems," by E. L. Wilson - June 1982 (PBBl l4B 080)AOs
UCB/EERC-82/0S "Hodel Study of Effects of Damage on the Vibration Properties of Steel Offshore Platforms," by F. Shahrivar and J. G. Bouwkamp - June 1982 (PB8l 148 742)AlO
UCB/EERC-82/06 "States ot the Art and PractiCe in the Optimum Seismic Design and Analytical Response Prediction of RIC Frame-Wall Structures," by A. E. Aktan and V. V. Bertero - July 1982 (PBBJ 147 7361AOS
UCB/EERC-82/07 "Further Study of the Earthquake Response of a Broad Cylindrical Liquid-Storage Tank Hodel," by G. C. Hanos and R. W. Clough - July 1982 (PBS3 147 744)All
UCB/EERC-B2/0B "An Evaluation of the Design and Analytical Seismic Response of a Seven Story Reinforced Concrete Frame - Wall Structure," by F. A. Charney and V. V. Bertero - July 1982(PB8l 157 628)A09
UCB/EERC-82/09 "Fluid-Structure Interactions: Added Mass Computations Cor Incompresaible Fluid," by J. S.-H. Kuo -August 1982 (PB8l 156 2B11A07
UCB/EERC-82/l0 "Joint-opening Nonlinear Mechanism. Interface Smeared Crack Hodel," by J. S.-H. Kuo -August 1982 (PBBl 149 19s)AOS
UCB/EERC-82/11 "Oynamic Response Analysis of Techi Dam," by R. W. Clough, R. M. Stephen and J. S.-H. Kuo -August 1982 (PB8l 147 496)A06
UCB/EERC-82/12 "Prediction of the Seismic Responses of RIC Frame-Coupled Wall Structures," by A. E. Aktan. V. V. Bertsro and M. Piazza - August 19B2 (PB8l 149 20l~09
UCB/EERC-82/l3 "Preliminary Report on the SMART 1 Strong Motion Array in Taiwan," by B. A. Bolt, C. H. Loh, J. Penzien, Y. B. Tsai and Y. T. Yeh - August 1982 (PB83 159 400)AlO
UCB/EERC-82/l4 "Shaking-Table Studies of an Eccentrically X-Braced Steel Structure," by H. S. Yang - Septe~er
1982 (PBel 260 778JAl2
UCB/EERC-B2/1s "The Performance of Stairways in Earthquakes," by C. Roha, J. W. Axley and V. V. Bertero - September 1982 (PB8l 157 69lJ A07
UCB/EERC-82/l6 "The Behavior of Submerged Multiple Bodiee in Earthquakes," by W.-~ Liao - Sept. 1962 (PBel 158 7091A07
UCD/EERC-Y2/17 "Effects of Concrete Types and Loading Conditions on Local Bond-Slip Rel~tionships," by A. D. Cowull, E. P. Popov and V. V. Bertero - September 1982 (PB8l 1Sl 5771A04
OCD/tERC-B2I1B
UCB/EERC-82/19
UC8/EERC-82/20
UCB/EERC-B2/21
UCB/EERC-82122
UCB/EERC-B2/23
UCB/EERC-82/24
UCB/EERC-82/25
UCB/EERC-82/26
UCB/EERC-82/27
UCB/EERC-83/01
UCB/EERC-83/02
UCB/EERC-83/03
UCB/EERC-83/04
UCB/EERC-83/0S
UCB/EERC-B3/06
UCB/EERC-B3/07
UCB/EERC-B3/0F!
UCB/EERC-B3/09
UCB/EERC-B3/10
UCB/EERC-83/11
UCB/EERC-Bl/12
UCB/EERC-Bl/IJ
UCB/EERC-B3/14
UCl/EERC-B3/15
UCB/EERC-B3/16
UCB/EERC-B 3/1 7
)3/
"Mechanical Behavior o~ She.sr Wall Vertical BOWldary Membarg, An Experimental Investigation," by M. T. Wagner and V. V. Bertero - October 19B2 (PBBl 159 764)A05
"Experimental Studies ot Multi-support Seismic Loading on Piping Systems," by J. H. Kelly and A. D. Cowell - Novel!lber 1982
"Generalized Plastic Hinge Concepts tor lD Beam-Column Elements," by P. F.-S. Chen and C. H. Powell" November 19B2 (PBOl 217 '81)All
"ANSR-III, General Purpose Computer Program for Nonlinear Structural An&lysis," by C. V. Oughourllan and C. H. Powell - November 19B2 (PBBl 251 330)A12
"Solution Strategies for StaticallY Loaded Nonlinear Structures," by J. W. Slmons and C. H. Powell -November 1982 (PBB3 197 970)A06
"Analytical Hodel of Deformed Bar Anchorages under Generalized Excitations," by V. Ciampi, R. Eligehausen, V. V. Bertero and E. P. Popov - November 19B2 (PBB3 169 532)A06
"A Hathematical Hodel tor the Response of Masonry Walls to Dynamic Excitations," by H. Sucuoglu, Y. Hengi and H. D. HeNiven - November 19B2 (PBB3 169 Oll)A07
"Earth~uake Response Considerations of Broad Liquid Storage Tanks," by F. J. C~ra - November 1982 (PBBl .51 215lA09
"Computational Models tor Cyclic Plasticity, Rate Dependence and Creep," by B. Hosaddad and C. H. Poweli - November 1982 (PBBl 245 B29lAOB
"Inelastlc Analysis of Piping and Tubular Structures," by M. Hahasuverachai and C. H. Powell - November 1982 .lPBBl 249 987lA07
"The Economic Feasibility of Seismic Rehabilitation of Buildings by Base Isolation," by J. M. Kelly -January 1983 (PB83 197 9BB)A05
"Seismic Homept Connections for Moment-Resisting Steel Frames," by E. P. Popov - January 19B3 (PB8l 195 4l2)A04
"Design of Links and Beam-to-Column Connections for Eccentrically Braced Steel Frames,· by E. P. Popov and J. O. Ka11ey - January 19B3 (PBBl 194 B1lIA04
"Numerical Techniques for the Evaluation of Soil-Structure Interaction Effects in the Time Domain," by E. Sayo and E. L. Wilson - February 1983· (PB83 245 60S) A09
"A Transducer for He.ssuring the Internal Forces in the Columns of a Frame-Wall Reinforced Concrete Structure," by R. Sause and V. V. Bertero - Kay 19B3 (FaB4 .ll9 4941A06
"Dynamic Interactions between Floating Ice and Offshore Structures," by P. Croteau - Hay 1983 (PR84 .ll9 4861Al6
"Dynamic Analysls of Multiply Tuned and Arbitrarily Supported .Secondary Syste"",," by T. Igusa and A. Der JC!ureghian - June 1983 (FB84 118 272IAll
"A Laboratory study of Submerged Multi-body Systems in Earthquakes," by C. R. Ansari - June 19B3 (PB8l 261 B42)Al7
"Effects of Transient Foundation Uplift on Earthquake Response of Structures," by C.-S. Yim and A. ~. Chopra - June 19B3 {PB8l 261 396)A07
"Optimal Design of Friction-Braced Frames under. Seismic Loading,~ by M, A. Austin and K, S, Pister -June 1983 (PBB4 119 2BBIA06
"Shaking Table Study of Single-Story Hasonry Houses. Dynamic Performance under Three Component Seis~c Input and Recommendations," by C. C. Hanos, R. w. Clough and R. L. Hayes - June 19B)
"Experimental Error propagation in pseudodynamic Testing," by P. B. Shing and S. A. Mahin - June 1981 (PBB4 119 270lA09
"Experimental and Analytical Predictions ot the Mechanical Characteristics of a LIS-scale Hodel of a 7-story RIC Frame-Wall Building Structure," by A. E. Aktan, V. V. Bertero, A. A. Chowdhury and T. Nagashima - August 19B3 (PBB4 119 21)IA07
"Shaking Table Tests ot Large-panel Precast Concrete Building System Assemblages," by H. C. Oliva and R. W. Clough - Auqust 1983
"Seismic Behavior of Active Beam Linka in Eccentrically Braced Frames," by K. D. Hjelmstad and E. P. Popov - July 19B3 (PBB4 119 676JA09
"System Identification of Structures with Joint Rotation," by J. S. Dimsdale and H. D. HeNiven -July 19B3
"Construction ot Inelastic Response Spectra for Slngle-Oegree-of-Freedom Systems," by S. Mahin and J. Lin - July 1983
/3")...-
UCB/EERC-BJ/19 "Interactive Computer Analysis Methods (or Predicting the Inelastic Cyclic Behaviour of Structural Sections," by S. Kaba and S. Hahin - July 19B1 (PBB4 192 012) A06
UCB/EERC-BJ/19 "E:ffects of Bond Deterioration on Hyster.etic Behavior of Reinforced Concrete Joints," by F.C. Filippou, E.P. Popov and V.V. Bertero - August 19B3 (PBB4 192 020) AIO
UCBjEE:RC-BJ/20 "Analytical and Experimental Correlation of Large-Panel Precast Building System Performance," by M.G. Oliva, R.W. Clough, M. Velkov, P. Gavrilovlc and J. Petrovski - November 19B3
UCB/EERC-BJ/21 "Mechanical Characteristics of Materials Used in a liS Scale Hodel of a 7-Story Reinforced Concrete Test Structure," by V.V. Bertero, A.E. Aktan, H.G. Harris and A.A. Chowdhury - September 19B) (PB84 19J 697) AOS
UCBIEERC-8JI22 "Hybrid Modelling of Soil-Structure Interaction in Layered Media," by T. -J. Tzong and J. Penzien -October 19B) (PBB4 192 178) AOB
UCB/EERC-B)/2J "Local Bond Stress-Slip Ralationships ot Deformed Bars under Generalized Excitations," by R. Eligehausen, E.P. popov and V.V. Bertero - October 1983 (PBB4 192 B48) A09
UCB/E:ERC-Bl/24 "Design Considerations for Shear Links in Eccentrically Braced Frames," by J.O. Malley and E.P. Popov -November 19B3 (PB84 192 186) A07
UCB/EERC-84/01 "Pseudodynamic Test Method for Seismic Performance Evaluation: Theory and Implementation," by P.-S. B. Shing and S. A. Mahin - January 1984 (PB84 190 644) AOB
UCB/EERC-B4/02 "Dynamic Response Behavior of Xiang Hong Dian Dam," by R.W, Clough, K.-T. Chang, H.-Q. Chen, R.M. Stephen, G.-L. Wang, and Y. Ghanaat - April 19B4
UCB/EERC-B4/03 "Refined Modelling of Reinforced Concrete Columns for Seismic Analysis," by S.A. Kaba and S.A. Hahin -April, 1994
UCB/EERC-B4/04 "A New Floor Response Spectrum Hethod for Seismic Analysis of Multiply Supported Secondary Systems," by A. Asfura and A. Der Klureghian - June 1994
UCB/EERC-84/0S "tarthquaJce Simulation Tests and Associated St:udies o·f a l/Sth-scale Model of a 7-story RIC Frame-Wall Test Structure," by V.V. Bertero, A.E. Aktan, F.A. Charney and R. Sause - June 1984
UCB/EERC-84/0G "R/C St:ructural Walls: Seismic Design for Shear," by A.E. Aktan and V,V. Bertero
UCB/EERC-84/07 -Behavior of Interior and Exterior Flat-Plate Connections Subjected to Inelastic Load Reversals," by H.L. Zee and J.P. Moehle
UCB/EERC-84/08 "Experimental Study of the Seismic Behavior of a two-story Flat-plate Structure," by J.W. Diebold and J. P. Moehle.
UCB/EERC-84/09 "Phenomenological Modeling of Steel Braces under Cyclic Loading," by K. Ikeda, S.A. Hahin and S. N. Denni tzakis - May 1994
UCB/E:ERC-84/l0 "EarthquaJce Analysis and Response of Concrete Gravity Dams," by G. Fenves and A.K. Chopra - August 1984
UCB/EERC-84/l1 "EAGD-84: A Computer Program for Earthquake Analysis of Concrete Gravity Dams," by G. Fenves and A.K. Chopra - August 19B4
UCB/E£RC-84/12 "A Refined Physical Theory Hodel for predicting the Seismic Behavior of Braced Steel Frames," by K. Ikeda and S. A. Mahin - Jul y 1994
UCB/EfRC-84/1J "Earthquake Engineering Research at Berkeley - 1984" - August 1994
UCB/EERC-84/14 "Moduli and Damping Factors for Dynamic Analyses ot Cohesionless Soils," by H.B. Seed, R.T. Wong, I.H. Idriss and K. Tokimatsu - September 1984
UCB/EERC-84/1S "The Influence of SPT Procedures in Soil Liquefaction Resiatance Evaluations," by H. B. Seed, K. TokLmatau, L. F. Harder and R, M. Chung - October 1994
UCBIEERC-84/l6 "Simplified Procedures for tha Evaluation of Settlements in Sands DUB to Earthquake Shaking," by K. Tokimatsu and H. B. Seed - October 1984
UCB/EERC-84/17 "Evaluation and Improvement of Energy ADsorption Characteristics of Bridges under Seismic Conditions," by R. A. Imbsen and J. Penzien - November 1984
UCB/EERC-84/l9 "Structure-Foundation Interactions under Dynamic Loads," by W. D. Liu and J. Penzien - November 1984
UCB/EtRC-94/19 "Seismic Modelling of Deep Foundations," by C.-H. Chen and J. Penzien - November 19B4
UCB/E:ERC-84/20 "Dynamic Response Behavior of Quan Shui Dam," by R. w. Clough, K.-T. Chang, H.-Q. Chen, R. H. Stephen, Y. t::hanaat and J.-II. Qi - November 1994
NA UCB/EERC-8S/01 "Simplifled Methods of Analysis for Earthquake Resistant Desiqn of BuUdings," by E. F. Cruz and A.K. Chopra - Feb. ·1985 (PBB6 112299/A5) A12
UCB/EERC-85/02 "Eseimation of Seismic Wave Coherency and Rupture Velocity using the SMART 1 Strong-MoHon Array Recordings," by N./I. Abrahamson - March 1985
UCB/EERC-85/03 "Dynamic Properties of a Thirty Story Condominium Tower: Building," by R. M. Stephen, E. L. W11son and N. Stander - April 1985 (PB86 llB965/115) A06
UCB/EERC-85/04 "Development ot Substructur:ing Techniques tor On-Line Compueer Coner011ed Seismic Performance Teseing," by 5, Dermiezak1s and 5, Mahin - February 1985 (PBIl6 1329H/AS) AOB
UCB/EERC-BS/05 "A Simple Model for Reinforcing Bar Anchorages undsr Cyclic Excitatione," by F.C. FiUppou - March 19B5 (PBB6 112919/115) A05
UCB/EERC-85/06 "Racking Behavior ot Wood-Framed Gypeum Panele under Dynamic Load," by M.G, Oliva - June 19B5
UCB/EERC-85/07 "Earthquake Analysis and Response of Concrete Arch Dams," by K,-L. Fok and A.K. Chopra - June 1985 (PB86 139672/AS) 1110
UCB/EERC-BS/OB "Effect of Inelastic Behavior on ths Analysis and Desiqn of Earthquaks Resistant Structures," by J.P. Lin and S.A. Mahin - June 19B5 (PB86 135340/AS) AOB
UCB/EERC-85/09 "Earthquake Simulator Testing of a Base-Isolated Bridge Deck," by J.M. Kelly, I,G. Buckle and H.-C, Tsai - January 1986
UCB/EERC-B5/10 "Simplified Analysis for Earthquake Resistant Desiqn of Concrete Gravity Dams,· by G. Fenves and A.K. Chopra - September 19B5
UCB/EERC-85/ll "Dynamic Interaction Effects in Arch Dams," by R.W. Clough, K.-T. Chang, H.-Q. Chen and Y. Ghanaae _ October 19B5 (PBB6 l35027/AS) A05
UCB/EERC-85/l2 "Dynamic Response of Long Valley Dam in the Mammoth Laks Earthquake Serles of May 25-27, 19BO," by S. Lai and H.R. Seed - November 19B5 (PBB6 142304/115) AOS
UCB/EERC-B5/l3 "A Methodology for Computer-Aided Desiqn of Earehquake-Resiotant Steel Seructures," by M.A. Austin, K.S. pister and S.A. Mahin - December 1985 (PBB6 lS94BO/AS) A10
UCB/EERC-85/l4 "Response of Tension-Leg Platforms to Vertical Seismic Excitations," by G.-S .• Liou, J. Penzien. and R.W. Yeung - December 1985
UCB/EERC-B5/1S -Cyclic Loading Test9 of Masonry S1ngle Piersl Volume 4 - Additional Tests with Height to Width Ratio of 1," by H. Sucuoglu, H.D. l~cNiven and B. Sveinsson - December 19B5
UCB/EERC-B5/16 "An Experimental Program for Studying the Dynamic Response of a Steel Frame with a Variety of Infi11 Partitions," by B. 'lanev and H.D. McNiven - December 19B5
UCB/EERC-B6/0l "A Study of Seismically Resistant Eccentrically Braced Steel Frame Systems," by K. Kasal and E.P. Popov -January 1986
UCB/EERC-86/02 "Design Problems in Soil Liquefaction," by H.B. Seed - February 19B6
UCB/EERC-B6/03 "Lessons Learned from Recent Earthquakes and Research, and Implications for: Earthquake Resistane Design of Building Structures in ehe United Staees," by V.V. Bertero - March 19B6
UCB/EERC-B6/04 "The Use of Load Dependent Vectors for: Dynamic and Earthquake Analyses," by P. ~ger, E.L. Wilson and R.W. Clough - March 1986
UaJ/EERC-86/05 "Two Beam'-To-Column Web·Connections," by K.-C. Tsa! and E.P, Popov - April 19B6
UCB!EERC-86/06 "Determination of Penetration Resistance for Coarse-Grained Soils using the Becker Hammer Drill," by L.F, Harder and H.B. Seed - May 19B6
