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GEOTECHNICAL INVESTIGATION
SOUTHEAST OUTFALL SYSTEM MODIFICATIONS
SAN FRANCISCO, CALIFORNIA
FOR
SAN FRANCISCO CLEAN WATER PROGRAM
CITY & COUNTY OF SAN FRANCISCO
Allstate Geotechnical Services
San Francisco • San Ramon • Oakland
JUNE 1986 World Trade Center, Suite 258, San Francisco, CA 94111 • Phone 415/788-8908
TABLE OF CONTENTS
PAGE
1. INTRODUCTION . 1
1.1 GENERAL STATEMENT 1
1. 2 PROJECT DESCRIPTION .1
1.3 WORK PERFORMED .... 3
2. FINDINGS 5
2.1 SITE CONDITIONS 5
2. 2 GEOLOGY 9
2. 3 EARTH MATERIALS 10
2.3.1 A r t i f i c i a l F i l l (Qaf) 11
2.3.2 Younger Bay Mud (Qyb) .12
2.3.3 Bay Side Sands (Qbs) 13
2.3.4 Older Bay Mud (Qob) 14
2.4 SUBSURFACE CONDITIONS 14
2.4.1 Booster Pump Station ....14
2.4.2 Proposed Pipeline 15
2.5 GROUNDWATER 17
2.6 FAULTS AND SEISMICITY 17
3. CONCLUSIONS AND RECOMMENDATIONS 22
3 • 1 PROJECT FEASIBILITY 22
3.2 SEISMIC DESIGN CONSIDERATIONS 22
3.2.1 Maximum Credible Earthquake 22
3.2.2 Risk Analysis and Design Earthquake 23
3.2.3 Site Response Analyses 28
3.2.4 Fault Rupture 29
3.2.5 Liquefaction 29
3.2.6 Lateral Spreading 30
3.2.7 Seismically Induced Strain ..30
3.2.8 Seismic Earth Pressures .....32
3.3 BOOSTER PUMP STATION .32
3.4 PIPE DESIGN 33
3.4.1 General 33
3.4.2 Foundation Design 34
3.4.3 Earth Loads 38
3.4.4 Surcharge Pressures 40
3.4.5 Modulus of Soil Reaction 40
3.4.6 Thrust Resistance 40
3.4.7 Pipeline Passing Below Shed A 41
3.5 EARTHWORK 42
3.5.1 Excavation characteristics 42
3.5.2 Trench Width 42
3.5.3 Trench B a c k f i l l 42
3.5.4 Pipe Bedding 43
3.6 CONSTRUCTION CONSIDERATIONS 44
3.6.1 Temporary Earth Pressures ' 44
3.6.2 Groundwater Control 45
3.6.3 Excavation Base S t a b i l i t y 45
3.6.4 Pile Driving 46
3.6.5 Construction Loads 46
3.6.6 Construction Induced Settlements 46
3.7 CORROSION 47
4. QUALITY CONTROL 48
5. CLOSURE ...49
6. REFERENCES 50
PLATES
PLATE 1.1
PLATE 1.2
PLATE 2.1
PLATE 2.2
PLATE 2.3
PLATE 2.4
PLATE 2.5
PLATE 2.6
PLATE 3.1
PLATE 3.2
PLATE 3.3
PLATE 3.4
PLATE 3.5
PLATE 3.6
PLATE 3.7
PLATE 3.8
PLATE 3.9
PLATE 3.10
PLATE 3.11
PLATE 3.12
Site Location Map
D r i l l Hole Location Map
Pre-1860 Shoreline of San Francisco
Regional Geology and Fault Map
Idealized Soil Profile
Idealized Transverse Profile Pier 80 South Deck
Legend for Soil Profiles
Earthquake Epicenter Map
Earthquake Acceleration Correlations
Earthquake Recurrence Curves
Seismic Hazard Analysis
Site Response for Profile 1
Site Response for Profile 2
Response Spectra at the Base of Pipeline - Profile 1
ATC Response Spectra
Bending Moments
Earth Load Coefficient - Cd
Vertical Surcharge Pressures
Lateral Surcharge Pressures
Pressure Distribution for Cantilevered Sheet Pile - Simplified Method
TABLES
TABLE 2.1 Active Faults
TABLE 3.1 Number of Seismic Events for Each Source
TABLE 3.2 Return Periods of Earthquakes on the Major Faults Near the Project Site
TABLE 3.3 Parameters for the Maximum Credible Earthquake and Design Earthquake
TABLE 3.4 Seismically Induced Pipe Strain During the Design Earthquake
APPENDIX A - SUPPORTING GEOTECHNICAL DATA A-1
EXPLORATION .A-1
SAMPLING A-2
LABORATORY TESTING A-3
Moisture Content And Density Tests A-3
Consolidation Test A-3
Unconfined Compression Tests A-4
Sieve Analysis Tests A-5
Torvane Shear Strength Tests A-5
Chemical Tests A-5
PLATES
PLATES A-1.1 throung A-1.14
PLATE A-2
PLATE A-3
PLATE A-4
PLATE A-5.1 & A-5.2
TABLE
TABLE A-1
APPENDIX B - SOIL CONTAMINATION
PLATE
PLATE B-1
D r i l l Hole Logs _..
Legend To D r i l l Hole Logs
Consolidation Test Data
Consolidation Test Time -Compression Curves
Unconfined Compression Tests
Chemical Tests
TESTS B-1
GC/MS Priority Pollutant Analysis
1. INTRODUCTION
1.1 GENERAL STATEMENT
This report presents the results of our geotechnical
investigation for the proposed Southeast Outfall System
Modifications in San Francisco, California. The project location
i s shown on Plate 1.1 - Site Location Map. The purpose of this
investigation was to explore the subsurface s o i l conditions and
to provide geotechnical findings, conclusions, and
recommendations for design and construction of the proposed
project.
1.2 PROJECT DESCRIPTION
The Southeast Outfall System discharges effluent from the
City of San Francisco's Southeast Sewage Treatment Plant into
San Francisco Bay about 700 feet beyond the east end of Pier 80
(Army Street Terminal). The proposed modifications to the system
include the placement of a new 60-inch-diameter reinforced
concrete sewer force main to replace the existing 54-inch-
diameter effluent line which extends from the Third Street
Bridge to the offshore diffuser located at the end of Pier 80.
It i s also planned to make modifications to the existing
Southeast Booster Pump Station. The modifications include
replacing the existing pipe in the manifold p i t with a larger
pipe and in s t a l l i n g larger pumps to increase effluent outflow
capacity.
1
The length of the proposed new pipeline alignment is
approximately 3640 feet and is shown on Plate 1.2. Its invert
w i l l be about 4 1/2 to 10 feet below the ground surface, ranging
from Elevation -6 feet to Elevation -12.5 feet. A l l elevations
referenced i n this report are based on San Francisco City Datum
(SFCD).
The new pipeline w i l l connect to the existing manhole
structure near the northwest corner of the Third Street Bridge.
The pipe w i l l extend east between the Reynolds Aluminum property
line and the Is l a i s Creek channel shoreline. Near the southeast
corner of the Reynolds Aluminum property, the pipe w i l l turn
northeast and extend to just south of a wire fence at the
southern edge of a truck t r a i l e r parking lot for Pier 80. The
pipe w i l l then turn east and run parallel to the fenceline. Near
the east edge of the truck t r a i l e r parking area, the pipeline
w i l l extend eastward parallel to the south edge of the Pier 80
terminal. The pipe i s to be placed above a relieving platform
located on the north side of the concrete deck. A portion of the
alignment w i l l be located below the building designated as Shed
A. This building extends over the relieving platform for
approximately 1000 feet. It is planned to demolish the eastern
543 feet of Shed A during proposed modifications to Pier 80.
Near the east end of Pier 80, the pipe w i l l turn north and
continue over the relieving platform along the east edge of the
terminal. The new pipe w i l l connect to the existing 54-inch-
diameter pipe which extends offshore to the diffuser.
2
1.3 WORK PERFORMED
The scope of our work was indicated in our proposal dated
February 14, 1986. The work performed for this investigation
included the following:
1. A review of the available geotechnical, geological, and
seismological data of the project area.
2. A f i e l d exploration which included d r i l l i n g 5 borings to
depths ranging from 17-1/2 to 146 feet. The locations of
the d r i l l holes for this investigation and the locations
of previous borings by ourselves and others are shown on
Plate 1.2 - D r i l l Hole Location Map. Bulk samples,
Standard Penetration Test samples, Modified California
Ring samples, and Shelby Tube samples of the earth
materials encountered were obtained for identification
and laboratory testing purposes. The logs of d r i l l holes
are presented in Appendix A - Supporting Geotechnical
Data.
3. Laboratory testing of samples obtained from d r i l l holes
to determine the engineering characteristics of the
various earth materials encountered. Moisture content,
dry density, Atterberg limits, grain size analyses,
unconfined compression, torvane shear strength, and
consolidation tests were performed. In addition, pH,
sulfate content, chloride content, and r e s i s t i v i t y tests
were performed on s o i l samples to determine their
corrosion potential. Test results and a description of
the test procedures are presented in Appendix A.
4. Laboratory testing of s o i l samples obtained from D r i l l
Hole DH-2 to determine whether the soils are
contaminated. Gas chromatography/mas s spectrometry for
semi-volatiles and o i l and grease tests were performed.
The test results and recommendations for further study
are presented in Appendix B - Soil Contamination
Analysis.
5. Development of geotechnical recommendations for the
proposed force main, including foundation schemes, pile
foundation design parameters, pipe embedment, temporary
shoring, earth pressure, b a c k f i l l requirements, and
u p l i f t forces.
6. Recommendations for protection of the pipe against
corrosion and galvanic actions.
7. Development of seismic design parameters and response
spectra, and evaluation of s o i l liquefaction potential
and seismically induced settlements.
8. Evaluation of pi l e lateral load capacity and deflection
by soil-structure interaction analyses.
9. Review and recommendation of improvements of the City's
proposed force main alignment along the wharf and review
of the foundation conditions of the existing force main
on the south side of the Islais Creek Channel to identify
potential soil-related problems.
4
10. Consultations with the City staff, the Port of San
Francisco engineering staff, and the Port's consultant,
CH2M HILL.
11. Preparation of this report.
2. FINDINGS
2.1 SITE CONDITIONS
The Southeast Outfall System i s located i n the Islais Creek
basin which was formerly a small bay adjoining San Francisco
Bay. Much of this basin was reclaimed from the bay during the
late 19th century and the f i r s t half of the 20th century by the
placement of a r t i f i c i a l f i l l . The original shoreline of Islais
Creek basin i s illustrated on Plate 2.1 - Pre-1860 Shoreline of
San Francisco. Prior to development, the basin was primarily
marshland and shallow t i d a l f l a t s .
Much of the Pier 80 area was reclaimed from the bay in the
early to mid-1960's by dredging a keyway trench along the
pierhead line through the younger bay mud and into the
underlying firm s o i l and then f i l l i n g the trench with dredged
sand. As the construction of the dike progressed, dredged sand
was placed over the younger bay mud in the area enclosed by the
dike. The existing 78-foot-wide concrete pier deck along the
north, south, and east perimeter of the site was constructed on
5
prestressed concrete piles ranging up to about 92 feet in length
driven into the sand dike. A concrete subgrade relieving
platform with a 15-foot-high retaining wall was built at the
inboard edge of the wharf.
The Is l a i s Creek Basin area generally i s experiencing
settlements on the order of one-half inch per year. However, the
central and eastern portions of Pier 80 have undergone
settlements up to 7 feet since placement of the dredged f i l l . As
a result of the large settlements, repairs were made at the east
end of the onshore portion of the existing effluent pipeline
last year.
The Southeast Outfall System, which was constructed in 1966
to 1967, begins at the Southeast Booster Pump Station located on
the south side of the Islais Creek Channel near the southwest
corner of the Third Street Bridge. The pump station is founded
on steel pipe piles which take support in sandy soils at about
elevation -70 feet. From the pump station, a 36-inch-diameter
pipe and a 42-inch-diameter pipe extend across Islais Creek
Channel. The pipes are embedded i n sand f i l l and are supported
on steel pipe piles over the entire crossing. The piles along
the south end of the crossing extend to about elevation -70
feet. Across the center and north end of the crossing, the piles
extend to about elevation -145 feet. The pipes are supported on
pile-supported trestles on the north and south creek banks. The
trestles have some battered piles to resist lateral loads.
From the manhole structure on the north bank of the channel,
an existing 54-inch-diameter pipe extends eastward across Third
Street. On the east side of Third Street, the pipeline turns
northward and continues along Third Street to Marin Street and
then eastward through Pier 80 to the sub-marine outfall in San
Francisco Bay. The existing alignment i s shown on Plate 1.2. The
alignment i s supported on f i l l from the manhole structure on the
north side of the Islais Creek Channel to the east end of the
Pier 80 sand dike. From the end of the sand dike to the end of
the diffuser, the alignment i s supported in younger bay mud.
The alignment of the proposed new pipeline was described
earlier i n the Project Description section. Stations were given
along this alignment by the San Francisco Clean Water Program.
The stations range from 1+00 at the manhole structure on the
west side of Third Street to 37+42 at the intersection of the
proposed pipeline and the existing pipeline at the east end of
the Pier 80 terminal.
At station 1+00, the new pipeline w i l l connect to the
existing manhole structure. The pipeline w i l l then cross Third
Street to Station 1+86. From Station 1+86 to Station 4+15, the
pipeline w i l l pass through a small park area located between the
Reynolds Aluminum property and the Islais Creek Channel. A
wooden shed exists in the northwest corner of the park. A small
retaining wall consisting of concrete panels and wooden piles
exists at the south edge of the park. Panels in the vicinity of
the Third Street Bridge have t i l t e d and have slipped down the
slope. The slope i s higher near the Third Street Bridge and is
covered with some large pieces of concrete.
7
From Station 4+15 to about Station 5+26, the new pipeline
w i l l cross one set of railroad tracks and w i l l pass adjacent to
an abandoned pier. ..Several pipelines extend from the pier to the-
shore and continue below the ground surface. It appears that
these abandoned lines may cross the proposed pipeline alignment.
During our investigation, o i l and grease were encountered in the
s o i l near these pipelines. Remedial work to remove the
contaminated s o i l may be required during pipeline construction.
Chemical laboratory analyses of these soils and recommendations
for further testing and study are contained in Appendix B of
this report.
From Station 5+26 to Station 9+27, the pipeline w i l l pass
through an undeveloped I s l a i s Creek shoreline area south of a
parking lot for container t r a i l e r s . The ground surface i s
covered with numerous large pieces of concrete, boulders, and
other debris along the shoreline area. The slope from the
parking lot to the water line i s relatively f l a t and some
vegetation i s growing between the concrete and boulders.
At Station 9+27, the pipeline w i l l pass beneath an existing
railroad trestle which i s located near the Army Street terminal
pier deck. On the east side of the trestle, the pipeline w i l l
pass through a retaining wall and w i l l continue on top of an
existing relieving platform located inboard of the concrete deck
at the south edge of Pier 80. The concrete relieving platform i s
supported on creosoted wood piles about 55 feet i n length driven
into the sand dike. The relieving platform i s about 3 to 3-1/2
feet thick, 25 feet wide, and the top of the platform is located
approximately 11 feet below the ground surface according to
design drawings.
8
From Station 11+70 to Station 16+27, the pipeline w i l l pass
below the south edge of the existing Shed A at Pier 80. The
waterside edge of the shed is supported on short piers ending on
the relieving platform. Although design drawings indicate the
clearance between the bottom of the shed's floor and the top of
the relieving platform i s only about 5-3/4 feet, a f i e l d
measurement on the west end of the shed by S.F. Clean Water
Program personnel indicated a clearance of about 7 feet.
The pipeline w i l l continue eastward on top of the relieving
platform along the south deck at Pier 80 to Station 34+74 where
i t turns northward and continues on top of the relieving
platform to Station 37+42. At Station 37+42, i t w i l l be
connected to the existing pipeline which extends offshore to the
diffuser.
2.2 GEOLOGY
The San Francisco Bay Area l i e s within the Coast Range
physiographic province of California which i s characterized by a
series of north-northwesterly trending mountains, valleys, and
faults. The geology of the San Francisco Bay Area was mapped by
Schlocker (1970). The map i s shown on Plate 2.2 - Regional
Geology and Fault Map. The San Francisco Bay Area as i t i s known
today came into existence i n mid-to-late Pleistocene time. Rocks
of the Franciscan Formation were deposited at the foot of the
continental slope from late Jurassic to mid-Cretaceous time. The
formations were folded and faulted by a series of earth
movements into the northwest trending structural patterns of the
9
central Coast Ranges. During the end of the Pliocene and the
Pleistocene epochs, the San Francisco Marin block was t i l t e d
toward the east, with the western edge forming the San Francisco
and Marin h i l l s , and the depressed eastern edge forming the
uneven depression in which the bay now l i e s . In Pleistocene
time, the trough was partially f i l l e d with sediments and became
San Francisco Bay as i t was flooded due to the rising in sea
level during the interglacial stages.
San Francisco Bay and the a l l u v i a l and estuarine deposits in
the Is l a i s Creek area occupy a structurally controlled basin
within the Coast Ranges province. Late Pleistocene and Holocene
sediments (less than 1.0 million years old) were deposited in
this basin as i t subsided (Atwater, Hedel, and Helley, 1977). In
the Is l a i s Creek area, these sediments rest on the serpentinites
and gabbros of the northwest trending Fort Point-Hunters Point
shear zone and are locally overlain by a r t i f i c i a l f i l l . Based on
the available geologic data, the depth to bedrock along the
proposed new pipeline alignment varies from about 200 to 250
feet (Bonilla, 1964). The depth to bedrock under the Southeast
Booster Pump Station i s about 255 feet.
2.3 EARTH MATERIALS
Earth materials encountered during this investigation
consist of 8 to 24 feet of a r t i f i c i a l f i l l (Qaf) underlain by
younger bay mud (Qyb). Three d r i l l holes, DH-1, DH-3, and DH-5
were extended below the younger bay mud into the underlying bay
10
side sands (Qbs). The thickness of younger bay mud at these
d r i l l holes was 80, 121, and 43 feet, respectively. D r i l l hole
DH-5 was extended through the bay side sands layer into older
bay mud (Qob). The thickness of the bay side sand layer in d r i l l
hole DH-5 was 20 feet.
Two idealized s o i l profiles included herein on Plates 2.3
and 2.4 have been drawn from d r i l l hole logs for this
investigation and from boring information from a previous
investigation by ourselves. The profiles represent generalized
s o i l sections interpreted from widely spaced borings. Soil
deposits may vary in type, strength and many other important
properties between points of observation and exploration.
2.3.1 A r t i f i c i a l F i l l (Qaf). F i l l materials encountered in the
exploratory program consist of layers of sand (SP), clayey sand
(SC), s i l t y sand (SM), gravelly sand (SP), sandy gravel (GP),
and s i l t y clay (CH), with varying amounts of cobbles, brick, and
wood. Also, the f i l l i n d r i l l hole DH-2 contains some o i l and
grease, possibly from leakage from nearby pipelines. Chemical
tests performed on the contaminated s o i l and recommendations for
further testing and study are included in Appendix B of this
report.
The relative density of the f i l l materials ranges from very
loose to medium dense, with most f i l l being very loose to loose.
Standard Penetration blow counts in the f i l l range from 2 to 31
blows per foot. Moisture contents range from 5 to 52 percent.
11
2.3.2 Younger Bay Mud (Qyb) • Younger bay mud i s the youngest
deposit in San Francisco Bay and i t consists of soft
unconsolidated sediments generally containing more than 90
percent clay and s i l t size particles. Deposition of the mud
extends from approximately 9,000 years ago to the present
(Atwater, et. a l . , 1977). Available information indicates that
normally, the composition of the younger bay mud ranges from 30
to 60 percent clay, 30 to 65 percent s i l t , and 1 to 10 percent
sand. Lenses and irregular segregations of 1/2 inch to several
feet thickness of fine to coarse sand or mollusk shells are
common i n younger bay mud in some places. Younger bay mud i s ,
generally, ' soft to firm and typically i t exhibits a highly
plastic, highly compressible behavior.
The younger bay mud encountered during the exploration
program i s primarily dark gray, soft to firm, high plasticity,
s i l t y clay (CH) with local sand lenses and occasional shell
layers. In addition, a dark brown, s t i f f , peat (Pt) and peaty
clay (OH) layer was encountered at the bottom of the younger bay
mud deposit in d r i l l holes DH-1 and DH-3. The thickness of the
peat layer ranged from 4 to 23 feet in the 2 d r i l l holes. Also,
a 4-foot-thick dark brown, s t i f f peat layer was encountered at
top of the younger bay mud deposit i n d r i l l hole DH-2.
Torvane and unconfined compression t r i a x i a l tests were used
to determine the shear strength of the younger bay mud samples.
The shear strength test values range from 260 pounds per square
foot (psf) at the top of the younger bay mud deposit to 1740 psf
in the peat layer in d r i l l hole DH-3. The shear strength of the
12
peat i s primarily attributable to the s t i f f , compressed, wood
like nature of the organics and the higher shear strength values
are not representative of the overall shear strength of the
younger bay mud.
The tested moisture content of the s i l t y clay layer of the
younger bay mud ranges from 53 to 90 percent. The moisture
content of the peat layers ranges from 38 to 155 percent. The
tested dry density of the younger bay mud for this investigation
ranges from 49 to 65 pcf.
2.3.3 Bay Side Sand (Qbs). The bay side sands may be comprised
of wind blown and a l l u v i a l sands deposited during a low sea
level associated with the Wisconsian glaciation. The bay side
sands are normally bounded above by younger bay mud and below by
older bay mud. Occasionally bay side sands may be underlain
directly by bedrock. The bay side sands are typically medium- to
fine- grained, dense to very dense sand. Induration i s generally
slight and attributable to the presence of s i l t and clay. The
maximum thickness of bay side sands in the San Francisco Bay is
approximately 50 feet.
During this investigation, bay side sand was encountered in
d r i l l holes DH-1, DH-3, and DH-5. The layer i s typically a
green-gray to gray, dense to very dense, medium to fine-grained
clayey sand (SC). The tested dry density and moisture content of
the bay side sand samples obtained ranged from 107 to 118 pcf
and 11 to 28 percent, respectively.
13
2.3.4 Older Bay Mud (Qob) • The texture of older bay mud is
similar to that of younger bay mud. The older bay mud unit,
however, has been overconsolidated by several thousands of
pounds per square foot due to both repeated dessication and the
weight of^overlying soils which were subsequently eroded. Older
bay mud i s believed to be primarily an estuarine clay with
subordinate a l l u v i a l sediments that were deposited during sea
level fluctuations associated with the Sangamon Interglacial
period.
Typically older bay mud comprises a light to dark gray-
green, s t i f f to very s t i f f , moderately to highly plastic s i l t y
clay (CH). Layers and lenses of dark gray to green-gray, dense
to very dense sand (SP-SM), gravelly sand (SW), clayey sand
(SC), and sandy clay (CL) are common throughout the unit. The
shear strength for the older bay mud layer i n d r i l l hole DH-5,
as determined by torvane tests, was 1700 psf. The tested dry
density and moisture content of the sample taken from this layer
was 64 pcf and 62 percent, respectively.
2.4 SUBSURFACE CONDITIONS
2.4.1 Booster Pump Station. D r i l l hole DH-5 was dr i l l e d on the
f i l l embankment near the northeast corner of the Southeast
Booster Pump station. The d r i l l hole was 10 feet north of the
retaining wall along the north edge of the pump station and
about 40 feet east of the existing force main. The thickness of
f i l l i n the d r i l l hole was about 14 feet. The f i l l i s generally
14
poorly compacted sand and clayey sand with gravel and brick
fragments. The f i l l i s underlain by about 43 feet of younger bay
mud which i s underlain by a 20-foot-thick layer of dense to very
dense bay side sands. Based on our findings i n this d r i l l hole,
the pipe piles supporting the booster pump station and the
southern portion of the force main crossing Islais Creek are
embedded about 10 feet into this bay side sand layer.
2.4.2 Proposed Pipeline. The pipe invert w i l l be between 5 and
10 feet below the existing ground surface from Station 1+00 to
the relieving platform inboard of the Pier 80 deck at about
Station 10+75. An idealized subsurface s o i l profile which i s
presented on Plate 2.3 has been drawn between the above stations
based on d r i l l hole logs for this investigation and from boring
information from previous investigations by ourselves and
others. The profile represents generalized s o i l sections
interpreted from widely spaced borings. S o i l deposits may vary
in type, strength and many other important properties between
points of observation and exploration.
Based on our exploration, the pipeline w i l l be founded
mainly i n a r t i f i c i a l f i l l between Stations 1+00 and 10+75.
However, between 6+QO and 8+75, the pipeline may be founded on
or s l i g h t l y below the boundary between younger bay mud and
a r t i f i c i a l f i l l . The f i l l thickness encountered during our
investigation varies from about 24 feet in d r i l l hole DH-1 to
about 8 feet i n d r i l l hole DH-4. The f i l l encountered is
generally poorly compacted heterogeneous granular f i l l with
varying amounts of s i l t , clay, gravel, bricks, and wood debris.
15
The heterogeneous nature of the f i l l makes i t impossible to
predict the composition or material properties of the f i l l at
any given point between Station 1+00 and the edge of_ the sand
dike at Pier 80 at about Station 8+75. From Station 8+75 to
9+75, the a r t i f i c i a l f i l l slopes down to the east at
approximately 5:1 (horizontal:vertical). From Station 9+75 to
10+75 the f i l l slope steepens to about 1:1. The f i l l between
Stations 8+75 and 10+75 i s anticipated to consist of a dense to
very dense, clayey sand or sandy clay for approximately the
upper 10 feet. Below this upper f i l l layer, the f i l l i s mainly a
hydraulically-placed medium to fine-grained sand. The hydraulic
f i l l i s generally medium dense to dense with localized zones of
loose and very dense sand.
The a r t i f i c i a l f i l l from Station 1+00 to 8+75 i s underlain
by approximately 80 to 120 feet of younger bay mud. The top of
the younger bay mud i s mainly very soft to soft, s i l t y clay.
From Station 8+75 to 10+75 the thickness of the younger bay mud
decreases from about 120 feet to approximately 45 feet at
Station 10+75. It i s anticipated that a dense bay side sand
layer underlies the younger bay mud along the proposed alignment
from Station 1+00 to 10+75. However, between Station 1+00 and
about 2+00, the bay side sand layer i s only about 5 feet thick.
The bay side sand layer i s underlain- by older bay mud which i s
underlain by bedrock.
The pipeline w i l l be founded on the relieving platform
inboard of the Pier 80 deck from Station 10+75 to the
intersection with existing pipeline at Station 37+42. As
discussed under Section 2.1 - Site Conditions, the relieving
16
platform i s founded on wood piles driven into the perimeter
containment dike which exists around the north, south, east
edges of Pier 80. The bottom of the sand dike i s founded in
s t i f f older bay mud or dense bay side sands. The bottom of the
sand dike along the proposed pipeline alignment varies from
about elevation - 100 to elevation -147. The inboard and
outboard slopes between the sand dike and the younger bay mud
are 1:1. A typical section view of the sand dike along the
proposed pipeline alignment i s shown on Plate 2.3.
2.5 GROUNDWATER
Groundwater was observed during the d r i l l i n g operations for
this investigation at a depth of 5 to 6 feet below the ground
surface, corresponding to Elevation -4-1/2 to Elevation -7-1/2
feet. Due to the close proximity of the pipeline alignment to
the Is l a i s Creek Channel and the granular nature of the f i l l
materials, i t i s expected that the groundwater elevation w i l l be
approximately the same as the water level in the channel.
2.6 FAULTS AND SEISMICITY
As part of the Coastal Ranges geologic province, the San
Francisco Bay Area i s within a region of high seismic activity.
Epicenters for the recorded earthquakes greater than Richter
Magnitude 2.5 of the area are shown on Plate 2.6 - Earthquake
Epicenter Map. The map also shows the major active faults in the
region.
17
The San Andreas fault dominates the tectonism, geology, and
physiography of the San Francisco Bay region. This fault, which
extends more than 700 miles northwestward from the Gulf of
California to Point Arena, represents the boundary between the
North American and Pacific Ocean crustal plates. Other major
active faults i n the region include the Hayward fault, Calaveras
fault, and the Seal Cove-San Gregorio fault. The Hayward fault
trends northwestward along the base of the h i l l s behind the East
Bay c i t i e s from Fremont northwest to Richmond. North of San
Pablo Bay, the Rogers Creek and Heaidsburg faults continue along
much the same trend. The Calaveras fault diverges northward from
the San Andreas fault south of Hollister and continues northward
along the eastern margin of the Santa Clara Valley and into the
Diablo Range. The San Gregorio fault trends northward across the
mouth of Monterey Bay and along the coast of San Mateo County.
The Seal Cove and associated faults north of Half Moon Bay may
represent a northward continuation of the San Gregorio fault.
A l l these faults trend northwesterly and display a similar
right-lateral, primarily horizontal movement. The proximity of
the site with respect to active faults is presented in Table 2.1
- Active Faults (Kiremidjian and Shah, 1978; Borcherdt, 1975).
Numerous other smaller active faults are present throughout the
region, but are farther from the site and not believed to be
capable of causing significant earthquake shaking within the
project area.
18
TABLE 2.1
ACTIVE FAULTS
Fault
Distance to
The Site
(miles)
Fault
Length
(miles)
Maximum
Richter
Magnitude
(assigned)
Maximum
Richter
Magnitude
(recorded)
San Andreas
Hayward
Calaveras
San Gregorio
Concord
Green Valley
7
11
20
16
23
28
745
45
71
84
12
24
8.3
7.7
7.7
7.5
6.3
6.6
8.3
6.7
6.7
6.1
5.4
5.0
There have been at least 17 recorded earthquakes since 1800
that have caused damage to structures in the San Francisco Bay
Area (Tocher, 1957). The five largest are discussed below.
June 10, 1836. The earthquake was attributed to movement on
the Hayward fault i n the East Bay. Ground rupturing took place
along the base of the Berkeley H i l l s from Mission San Jose to
San Pablo. The Richter Magnitude of this earthquake is believed
to be about 7.
June 1838. The earthquake originated on the San Andreas
fault and resulted in surface rupturing from Santa Clara to San
Francisco. The Richter Magnitude of this earthquake is believed
to be about 7.
19
October 8, 1865. The earthquake was centered on the San
Andreas fault i n the Santa Cruz Mountains and resulted in severe
damage to the entire Bay Area. The Richter Magnitude of this
earthquake i s also believed to be about 7.
October 21, 1868. The earthquake was centered on the
Hayward fault. Surface faulting was about 20 miles. The maximum
horizontal displacement was 3 feet. Damage to buildings occurred
in San Francisco and San Jose, along with 30 f a t a l i t i e s . The
Richter Magnitude of this earthquake i s also believed to be
about 7.
Apr i l 18, 1906. This earthquake was probably California's
greatest shock. Rupture occurred along 270 miles of the San
Andreas fault from San Juan Bautista to southern Humboldt
County. The resultant maximum vertical displacement was 6 to 8
feet at Shelter Cove, and the maximum horizontal displacement
was about 20 feet at the south end of Tomales Bay. Structures in
the San Francisco Bay Area were severely damaged and over 700
f a t a l i t i e s occurred. It had a Richter Magnitude of 8.3.
The Southeast Outfall System l i e s within the Fort Point -
Hunters Point shear zone. The Fort Point - Hunters Point shear
zone was f i r s t described by Schlocker (1974) from outcrops of
sheared serpentinite in Potrero H i l l and Hunters Point. It forms
an indistinct boundary between the graywacke, chert, greenstone
and shale of the Central highlands belt and the massive
graywacke and shale of the Nob H i l l belt to the east. The shear
zone comprises a 5,000- to 8,000-foot wide belt of serpentinite
and cataclasite, with inclusions of sandstone, that extends from
Fort Point southeastward through Potrero H i l l and the Hunters
20
Point area. This shear zone, like
Fault, and City College fault
evidence of recent movement or
considered active.
the San Bruno Fault, Hillside
zone, does not display any
activity, and thus i s not
21
3. CONCLUSION AND RECOMMENDATIONS
3.1 PROJECT FEASIBILITY
Based, on the f i e l d exploration, laboratory testing, and
geotechnical analyses performed, i t i s feasible to construct the
proposed Southeast Outfall System modifications, provided the
recommendations presented in this report are considered in the
project design and construction.
3.2 SEISMIC DESIGN CONSIDERATIONS
3.2.1 Maximum Credible Earthquake- A maximum credible
earthquake i s the largest earthquake that a given fault appears
capable of generating. The maximum credible earthquake that
could affect the site would be one with Richter Magnitude 8.3
occurring along the San Andreas fault at approximately 7 miles
from the project site.. The estimated return period of a Richter
Magnitude 8.3 earthquake on the San Andreas fault i s
approximately 230 years (Kiremidjian and Shah, 1978). The
duration of strong shaking for this earthquake would be
approximately 80 seconds. The maximum credible earthquake would
have a predominant period of approximately 0.4 seconds at
bedrock.
22
Correlations between distance from a causative fault and
peak bedrock accelerations have been developed and are shown on
Plate 3.1 - Earthquake Acceleration Correlations (Seed and
Idriss, 1983). Based_on these correlations, a maximum credible
earthquake occuring on the San Andreas fault would generate a
peak bedrock acceleration of 0.55 g.
3.2.2 Risk Analysis and Design Earthquake. In order to
evaluate the s t a t i s t i c a l probability of a given earthquake
occurring during the l i f e of the project, an analysis was
performed based on the procedures and data developed by
Kiremidjian and Shah (1975).
The number of earthquake events for each of the major faults
in the general v i c i n i t y of the project site are li s t e d in Table
3.1. Because the time period of the data may not be long enough
to include the greatest possible magnitude earthquakes that may
have occurred in the past, the maximum Richter magnitude that i s
assigned i s different and in most cases higher than the maximum
observed value.
23
TABLE 3.1
Number Of Seismic Events For Each Source
Fault Source
Number of Records
San Gregorio-Palo Colorado 106
San Andreas North 280
Hayward-Calaveras 321
Maximum Maximum Focal Richter Magnitude Richter Magnitude Depth
Assigned Recorded (Km)
7.5
8.3
7.7
6.1
8.3
6.7
10
10
10
The return periods for earthquakes of various magnitudes on
the above faults were calculated by a regressional analysis. The
results are presented in-Table 3.2 and on Plate 3.2.
24
TABLE 3.2
Return Periods of Earthquakes On The Major Faults
Near The Project Site
Return Period (years)
Richter Magnitude San Andreas Hayward-Calaveras San Gregorio
M Fault-North Faults Fault
8.3 230
8.0 163
7.7 800
7.5 91 570 400
7.0 50 242 190
6.5 28 103 92
6.0 16 44 44
5.5 9 19 21
5.0 5 8 10
The above data present the recurrence of specific magnitudes
of earthquakes with respect to their causative faults. It is
also necessary to determine the probability that a given number
of specific magnitude earthquakes w i l l occur anywhere on a
particular fault during the l i f e of the structure.
25
Seismic hazard evaluation of the project was based on
procedures and data developed by Kiremidjian and Shah (1975).
Using the return periods for various peak bedrock accelerations
and a correlation between service l i f e of structures, return
period, and risk level, also by Kiremidjian and Shah (1975), the
probability of occurrence for various peak bedrock accelerations
was computed for structures with a service l i f e of 50 years. The
computed values are presented graphically on Plate 3.3 - Seismic
Hazard Analysis.
However, the attenuation relationship for bedrock
acceleration used in the Kiremidjian and Shah analysis i s that
developed by Esteva (1974). The Esteva attenuation relationship
tends to have higher attenuation for small earthquakes but lower
attenuation for large earthquakes, compared with other commonly
used attenuation functions. Another seismic hazard analysis was
performed u t i l i z i n g the computer program EQRISK (McGuire, 1976)
and using the attenuation relationship developed by Schnabel and
Seed (1972). The probability of exceedence for a 50-year design
l i f e i s also shown on Plate 3.3. In addition, probability of
exceedence for the San Andreas fault as a single source was
computed and i s also presented on Plate 3.3.
As shown on Plate 3.3, the probability of exceedence curve
determined by the computer program EQRISK shows higher bedrock
acceleration than that determined by Kiremidjian and Shah for a
probability of exceedence greater than 20 percent. The upper
envelope of the curves by EQRISK and Kiremidjian and Shah was
used for site response analyses.
26
For the type of the structure under consideration, i t seems
to be appropriate to select a peak bedrock acceleration with a
50 percent probability of exceedence during a 50-year structure
l i f e as i t s operating level design earthquake. Based on the
above recommended probability of exceedence curves, the peak
bedrock acceleration for this level of earthquake i s 0.35 g.
The significant parameters for the maximum credible
earthquake and recommended design earthquake are presented in
Table 3.3.
TABLE 3.3
Parameters For The Maximum
Credible Earthquake And Design Earthquake
Earthquake
Peak Bedrock
Richter Acceleration at
Magnitude The Site (g)
Approximate
Epicentral
Predominant Distance
Period From Site
(Seconds) (Miles)
Maximum
Credible
Earthquake 8.3 0.55 0.40
Design
Earthquake 6.5 0.35 0.28
27
3.2.3 Site Response Analyses. One-dimensional, free-field site
response analyses were conducted for two generalized s o i l
profiles. Profile 1 represents the average s o i l conditions
beneath the existing pier. Profile 2 represents the s o i l
conditions i n the undeveloped area. The analyses were conducted
using the computer program SHAKE (Schnabel et a l . , 1972) which
determines the response of a horizontally layered, linear
viscoelastic system to input earthquake rock motions by the
method of wave propagation. Non-linear s o i l behavior is
approximated by the use of strain-dependent, equivalent linear
s o i l properties (Seed and Idriss, 1970). The response of the
s o i l profiles was obtained for the maximum credible earthquake
and design earthquake.
The maximum accelerations and equivalent cyclic shear stress
ratios at various depths were calculated. The results of these
analyses are presented on Plates 3.4 and 3.5. The results show
that the maximum accelerations at the base of the pipe are as
follows:
Response spectra at the base of the pipe were developed for
both earthquake levels and for damping ratios of 2, 5, and 10
percent for Profile 1. The results are shown on Plate 3.6.
Profile 1 Profile 2
Maximum Credible Earthquake
Design Earthquake
- l l g
-07g
.17g
.09g
28
The corresponding response spectra recommended by ATC
(Applied Technology Council) for soft to medium s t i f f clays and
sands normalized to the maximum accelerations l i s t e d above are
shown on Plate 3.7.
3.2.4 Fault Rupture. No known faults are known to cross the
alignment of the proposed effluent line. Therefore, the
potential risk of damage due to fault rupture is minimal.
3.2.5 Licjuefaction. Soil liquefaction i s a phenomenon in which
saturated (submerged) cohesionless soils can be subject to a
temporary loss of strength due to the build-up of excess pore
water pressure, especially during cyclic loadings such as
induced by earthquakes. In the process, the s o i l acquires a
mobility sufficient to permit both horizontal and vertical
movements, i f not confined. Soils most susceptible to
liquefaction are loose, clean, saturated, uniformly graded,
fine-grained sands. S i l t y sands may also liquefy during strong
ground shaking.
The exploratory borings show that the f i l l materials in the
undeveloped area are generally very loose with Standard
Penetration blow counts mostly below 10 blows per foot.
Therefore, we believe that the a r t i f i c i a l f i l l i n this area has
a moderate to high potential of liquefaction. Liquefaction of
the a r t i f i c i a l f i l l could result in significant ground movement,
possibly damaging portions of the proposed pipeline.
29
3.2.6 Lateral Spreading. Lateral spreading of the a r t i f i c i a l
f i l l may occur as a result of the design earthquake. Ground
movement of this type was the cause of nearly a l l major pipeline
breaks during the 1906 San Francisco earthquake (Youd and Hpose,
1978). The shoreline slopes in the undeveloped area of the
project site have a moderate to high potential for lateral
spreading and provisions should be made to allow for repair of
damaged f a c i l i t i e s i f a major earthquake should occur in the
future.
3.2.7 Seismically Induced Strain. Underground structures may
be damaged by seismic ground shaking or vibration, even though
an actual fracture or s l i p of the ground surface does not occur.
The axial and bending strains induced in a pipeline by ground
shaking can be estimated from the following equations (Newmark,
1967):
Axial Strain: € m = + V m/c
Bending Strain: K = a m/c2
Axial strain of the pipe
Soil particle velocity
Soil particle acceleration
Wave propagation velocity i n the direction of
the pipe axis
Reciprocal of the radius of curvature
Where G.m
vm am = c =
k =
30
The wave velocities in the direction of the pipe axis can be
evaluated using the relationship presented in Coats (1980). It
is recommended that the compressive wave velocity (Vp) be used
for the axial wave propagation velocity and the shear_ wave
velocity (Vs) be used for the curvature wave propagation
velocity. Peak ground surface particle velocities were evaluated
based on the empirical relationship between peak acceleration
and velocity developed by Newmark (1973), which suggests a
velocity/acceleration ratio of 48 in/sec/g for alluvium.
For the design earthquake of Richter Magnitude 6.5, the
following values may be used:
V m = 14 inches per second (1.2 feet per second) in s o i l
a m = 0.3g i n s o i l
Vp = 2,500 feet per second i n s o i l
V s = 1,000 feet per second in s o i l
Using the above equations and the velocity and acceleration
values, seismically induced pipe strain was computed and i s
presented in Table 3.4.
31
TABLE 3.4
Seismically Induced Pipe Strain
During The Design Earthquake
Axial Strain Bending Strain
(radians/foot) Pipe Location (feet/foot)
Soil 4.8 x 10"4 1.0 x IO - 5
3.2.8 Seismic Earth Pressures. The increase in earth pressures
that would be produced by the design earthquake has been
estimated using the procedures suggested by Seed and Whitman
(1970) for earth retaining walls. "A rectangular pressure
distribution of 6 pounds .per cubic foot (pcf) times the height
of the buried wall can be used for design.
3-3 BOOSTER PUMP STATION
Our visual observation during the f i e l d exploration
indicates that the dual force main at the booster pump station
at the south side of Islais Creek appears to be stable. However,
slope s t a b i l i t y evaluation of the structure is not within the
scope of this study. We w i l l investigate the s t a b i l i t y further
at your request.
32
The lateral capacity of the existing piles was evaluated
based on the method outlined i n the Navy * s NAVFAC DM-7.2
publication dated May 1982. The computations were performed by
f i r s t assuming level ground conditions. The resulting lateral
loads were then multiplied by a factor of 0.3 to account for the
reduction of passive resistance due to the 2:1 slope near the
piles. The f i l l condition as determined by our recent boring i s
very loose. The coefficient of variation of subgrade reaction
("f" factor) for this condition was assessed to be about 5
tons/ft 3.
The results of the analysis show that, for a recommended
maximum lat e r a l deflection of 1/2 inch at the top of the pile,
the maximum lateral capacity of the existing steel pipe piles i s
about 1.5 kips per p i l e . It should be noted that the batter
piles which were incorporated in the existing foundation system
also provide a significant lateral resistance.
3.4 PIPE DESIGN
3.4.1 General. A 60-inch diameter pipe w i l l be installed by
the cut-and-cover method in trenches about 10 feet deep. The
pipe w i l l be located in f i l l , younger bay mud, and on the
relieving platform. External loads on the pipe w i l l include
loads due to the overlying earth materials, loads due to
construction a c t i v i t i e s , t r a f f i c loads, loads due to nearby
33
structures and the overlying railroad, and earthquake induced
loads. It is recommended that the pipe be designed to resist the
imposed loads with a minimum factor of safety of 1.5 and/or an
acceptable amount of deflection as recommended by the
manufacturer.
3.4.2 Foundation Design. Based on our understanding of the
s o i l conditions along the proposed pipeline alignment, we
believe that i t i s feasible to support the pipe on either the
existing f i l l or piles for the pipe section between the Third
Street and the concrete deck of Pier 80. Under Pier 80, the pipe
w i l l be supported on the relieving platform. The two foundation
schemes are discussed below.
Pipe Supported on Existing F i l l - To support the pipe on the
existing f i l l , a special pipe bedding must be provided and
anticipated large settlements must be considered in the pipe
design. Specific pipe bedding recommendations are presented in
Section 3.5.
Available settlement data in the Islais Creek Basin area
indicates that areal settlement i s occurring at a rate on the
order of one-half inch per year due to consolidation of the
younger bay mud under the weight of the a r t i f i c i a l f i l l . Based
on this settlement data and the results of the consolidation
test in d r i l l hole DH-1, settlement of the pipe section in the
undeveloped area east of Third Street is estimated to be about 2
feet i n 50 years.
34
As indicated in the Subsurface Conditions section earlier i n
this report, the edge of the sand dike begins at about Station
8+75. From Station 8+75 to 10+75, the f i l l thickness beneath the
pipeline alignment increases from approximately 8 to 130 feet.
The younger bay mud thickness in this interval decreases from
about 120 feet at Station 8+75 to 45 feet at Station 10+75. The
relieving platform begins at about Station 10+75. It i s
estimated that the settlement of a pipe supported on the f i l l
between Station 8+75 and 10+75 w i l l vary from about 1 to 1-1/2
feet in 50 years.
The settlement for the pipe section inboard of Pier 80 w i l l
be the same as that of the relieving platform. Based on the
settlement monitoring data at Pier 80, we anticipate that
additional future settlements of the pipe inboard of Pier 80
w i l l be about 1 foot i n 50 years.
Because of the variation i n the anticipated settlement for
the various sections of the pipe, differential settlements of
the pipeline for the different supporting conditions may be as
much as 1 foot. In addition, because the f i l l materials beneath
and around the pipeline are not homogeneous, both in terms of
material type and density, local differential settlements of
several inches may occur over a 50 year period. We recommend
that flexible joints be incorporated to accomodate such
differential settlements. Bedding material recommendations for
the pipeline-on-existing-fill alternative are included later in
this report.
35
Pipe Supported on Piles. The pipe section between Third Street
and the Pier 80 concrete deck may be supported on piles taking
support i n the dense bay side sands. We recommend that
prestressed precast concrete square piles with a minimum width
of 12-inch and a minimum of 5 feet of embedment in the bay side
sands be used. It may be preferrable to use 14-inch-square piles
due to p i l e length and other structural reasons. For these
conditions and provided downdrag loads on the piles are reduced
as discussed i n the following paragraph, an allowable downward
capacity of 50 and 70 tons may be used for 12-inch-square and
14-inch-square piles, respectively. This allowable capacity may
be increased by one-third for seismic and/or wind loading.
Downdrag or negative skin f r i c t i o n due to the consolidation
of the younger bay mud. under the existing f i l l should be
minimized to avoid further reduction of the p i l e capacities. It
is recommended that the entire pile length with the exception of
the lower 5 feet be coated with bitumen to reduce downdrag
loads. In addition, i t i s recommended that a slightly oversized
hole be d r i l l e d i n the f i l l to protect the bitumen coat during
driving.
Our borings indicate that the depth of the bay side sand
layer i n this area varies from about 100 feet to 140 feet.
Therefore, we anticipate that the p i l e lengths w i l l be between
105 feet and 145 feet. However, in the v i c i n i t y of the existing
manhole structure at Station 1+00 and under Third Street, the
bay side sand layer i s only a few feet thick and cannot provide
adequate p i l e support. We recommend that piles in this area be
driven to a similar t i p elevation as the piles supporting the
manhole structure. Based on previous borings and pile driving
records by others, we anticipate p i l e t i p elevations of about
-145 feet.
36
As discussed previously, the edge of the sand dike begins at
about Station 8+75. We recommend that the piles between Station
8+75 and Station 10+00 be extended into the bay side sand layer
as discussed previously. We recommend p r e d r i l l i n g through the
entire f i l l depth between these stations. Between Station 10+00
and the relieving platform, the piles may be terminated in the
sand dike at about elevation -50 feet. The piles terminating in
the sand dike should not be coated with bitumen. Some
predrilling may be needed to reach the recommended t i p
elevation.
Settlements of the piles terminating i n the bay side sand
layer are anticipated to be less than 1/2 inch. As discussed
earlier in the report, i t i s expected that the sand dike w i l l
settle about 1 foot in the next 50 years. Therefore,
d i f f e r e n t i a l settlements on the order of 1 foot should be
expected in the vi c i n i t y of Station 10+00. We recommend that
flexible pipe joints be used in this area.
Alternatively, shorter piles extending into' the lower
portion of the younger bay mud may be used to reduce the amount
of d i f f e r e n t i a l settlement of the pipe. Recommendations w i l l be
provided i f this alternative is to be considered.
Lateral load capacities were computed for 12-inch-sguare
piles supporting the pipe between Station 1+00 and the relieving
platform. The lateral load capacity of individual piles should
be limited to 5.7 kips for 1/2 inch l a t e r a l deflection. Bending
moments along the length of the p i l e caused by different
horizontal forces applied at the top of the p i l e were calculated
and the results are shown on Plate 3.8 - Bending Moments. The
curves are only applicable for a hinged and condition.
37
3.4.3 Earth Loads
Pipes Supported on Piles. Pipes supported on piles should
be designed to resist f u l l overburden pressures. Overburden
pressures may be calculated as the pressure exerted by a f l u i d
weighing 125 pcf above ground water level and 60 pcf below
ground water level. Downdrag loads can be taken as 200 pounds
per square foot (psf) acting on vertical planes extending from
the ground surface to the springline of the pipe.
Pipes Supported on F i l l and S o i l . Loads on the pipe due to
the overlying s o i l w i l l be dependent upon the depth of
placement, the b a c k f i l l type and placement, and the type of
pipe. It i s l i k e l y that the pipe w i l l be placed in trenches with
near vertical sides. No major f i l l i s contemplated above the
existing ground surface and the pipe w i l l thus be i n a "trench"
condition.
The earth load on the pipe may be calculated using formulas
developed by Marston (1930). For a r i g i d pipe in a "trench"
condition, the formula i s :
CdWBd
2
Where: Vertical load on the pipe in pounds per
unit length
An empirical
Marston (1930)
coefficient described by
38
W = Unit weight of the trench b a c k f i l l material
in pcf
B d = Width of the trench at the top of the pipe
in feet
When using this equation, the empirical coefficient, C d i can
be obtained from Plate 3.9 - Earth Load Coefficient C d i and the
unit weight of the trench b a c k f i l l , W, can be assumed as 130
pcf.
If the pipe is flexible and the bedding surrounding the pipe
is placed as recommended in this report, then the bedding and
earth materials surrounding the pipe w i l l carry a portion of the
earth load and the above equation can be modified to:
w
c = CdWBcBd
Where: B c = Outside diameter of the pipe i n feet
It i s believed that most of the pipe w i l l be placed in the
"trench" condition. However, i f the width of the trench is.
greater than twice the diameter of the pipe, then the pipe may
be i n an "embankment" condition and the above equations w i l l not
apply. The earth load should then be calculated on the basis of
Marston's formula for "embankment" conditions (Marston, 1930).
39
3.4.4 Surcharge Pressures. For any surcharge applied on the
pipe, the pressures on the pipe may be estimated using the
pressure diagrams presented on Plate 3.10 for vertical surcharge
pressures and Plate 3.11 for lateral surcharge pressures.
3.4.5 Modulus of Soil Reaction. Flexible and semi-rigid pipes
are typically designed to limit deflections caused by the
applied loads. These deflections can be estimated with the aid
of equations developed by Spangler (1941). A modulus of s o i l
reaction of 100 pounds per square inch (psi) can be assumed for
pipe supported in a r t i f i c i a l f i l l and younger bay mud.
3.4.6 Thrust Resistance. Where the proposed pipeline changes
direction abruptly, resistance to thrust forces can be provided
by mobilizing f r i c t i o n a l resistance between the pipe and
surrounding s o i l , by the use of a thrust block, or by a
combination of the two.
The f r i c t i o n a l resistance can be calculated u t i l i z i n g
coefficients of f r i c t i o n between the pipe and adjacent b a c k f i l l
of 0.30 for the steel pipe. - Pipe segments may be connected by
tension j oints capable of transmitting the required thrust
forces i f more than one segment of pipe i s needed.
40
Passive resistance at a thrust block may be used instead of,
or i n conjunction with, f r i c t i o n a l resistance to resist pipe
thrust. For thrust blocks that are used in a r t i f i c i a l f i l l or
younger bay mud, an equivalent f l u i d pressure of 190 pcf above
the water table and 95 pcf below the water table should be used
for design. These low values are dictated by the soft and
yielding nature of the s o i l .
3.4.7 Pipeline Passing Below Shed A. As described in Section
2.1, a test p i t excavated under the direction of the S.F. Clean
Water Program showed a clearance of about 7 feet between the
bottom of Transit Shed A's floor and the top of the relieving
platform near the west end of the Shed. The clearance between
the bottom of the Transit Shed A's The clearance at this
location i s adequate for the proposed 73-1/2 inch O.D. pipe.
However, the original design drawings indicate that the
clearance i s only 5-3/4 feet. If i t is found that there is
inadequate clearance for the proposed pipe at other locations,
the following alternatives may be considered:
1. Use dual pipes and reduce the pipe size.
2. Change the pipe shape to rectangular.
3. Modify the foundation of the existing shed. One approach
is to d r i l l short piers and have this part of the
structure span over the pipe and be supported on the
relieving platform.
41
For the eastern portion of the shed, CH2M-Hill and AGS w i l l
raise the new foundation in the modification design to provide
sufficient clearance.
3.5 EARTHWORK
3.5.1 Excavation Characteristics. Excavation for the pipeline
w i l l encounter primarily a r t i f i c i a l f i l l . The a r t i f i c i a l f i l l i s
composed of a wide range of materials including gravelly sand,
s i l t y clay, s i l t y sand, cobbles, glass, and brick fragments.
However, we do not expect that excavation of these materials
w i l l present major d i f f i c u l t i e s .
3.5.2 Trench Width. Minimum trench widths should be provided
in order to ensure uniform support and to minimize external
loads on the pipe. The width of the b a c k f i l l , as measured from
the side of the pipe to the side of the trench, should be a
minimum of 12 inches for r i g i d pipes. For flexible or semi-rigid
pipes, the width of the b a c k f i l l should be a minimum of 18
inches i n a r t i f i c i a l f i l l , and 24 inches i n younger bay mud.
3.5.3 Trench B a c k f i l l . Trench b a c k f i l l may consist of
excavated on-site soils provided they are free of organics and
debris, have been screened to remove particles larger than six
inches in diameter, have a plastic l i m i t less than 12 percent
42
and a liquid limit less than 35 percent, and have been properly
blended and dried to near optimum moisture content. Imported
f i l l may also be used provided that the material i s approved by
a qualified geotechnical engineer prior to placement.
Trench b a c k f i l l should be placed in layers not exceeding
eight inches in uncompacted thickness and should be compacted to
90 percent relative compaction as determined by standard test
method ASTM D1557. The upper three feet of trench b a c k f i l l
should be compacted to 95 percent relative compaction in areas
where t r a f f i c or structural loads are anticipated. An
appropriate compaction method should be used to avoid damaging
the pipe.
3.5.4 Pipe Bedding. The proposed pipeline should be completely
surrounded with bedding material to provide uniform support and
protection. Pipe bedding should consist of crushed rock ranging
i n size from 1/4 inch to 1-1/2 inches in diameter for the pipe
sections founded on gravelly miscellaneous f i l l and should
consist of medium to coarse-grained sand, pea gravel, or crush
of rock of less than 1/2 inch in size for the sections of pipe
founded on younger bay mud and fine to medium-grained sand f i l l .
Where the pipe i s to be supported on the gravelly miscellaneous
f i l l , sand should not be used as bedding because i t may be
subjected to migration into the surrounding porous f i l l , leaving
the pipe unsupported. The material should be of uniform
gradation, and should contain less than three percent by weight
passing the No. 200 sieve.
43
Pipe bedding should be placed beneath the pipe with a
minimum thickness of 18 inches over a r t i f i c i a l f i l l and younger
bay mud. The material should be placed to cover the proposed
pipe by a minimum of six inches.
A l l bedding material should be placed carefully to achieve
uniform contact with the pipe and a minimum relative compaction
of 90 percent as determined by standard test method ASTM D1557.
Compaction by jetting or flooding should not be permitted.
3.6 CONSTRUCTION CONSIDERATIONS
3-6.1 Temporary Earth Pressures. The use of sloping sides i n
the pipeline excavation may not be practical at a l l locations.
Excavation at these locations w i l l require a shoring system for
support.
Temporary, internally braced and shored excavations w i l l be
subjected to the generalized earth pressures depicted on Plate
3.12 - Lateral Pressures on Temporary Structures. Lateral
pressures due to surcharge loading, including construction
equipment, should also be considered in design of the temporary
bracing system.
44
3.6.2 Groundwater Control. The lowest invert elevation of the
pipe is at -12.5 feet in the undeveloped area, which w i l l be
lower than the mean lower low water level (MLLW). Therefore,
groundwater w i l l l i k e l y be present in the trench and dewatering
w i l l be required. Dewatering w i l l be d i f f i c u l t i n some.areas due
to the highly permeable nature of the a r t i f i c i a l fi!3r and the
close proximity of the Islais Creek Channel.
To avoid the problems associated with dewatering in the
undeveloped area, i t i s recommended that the excavation be
isolated from the groundwater by an impervious barrier such as
steel sheet p i l i n g . The barrier should extend into the
underlying younger bay mud. Steel sheet p i l i n g w i l l act as a
ground water barrier only i f i t extends into an impermeable
layer and maintains the interlock between sheets. Where the
sheet pi l e interlock f a i l s to retain the groundwater, well
points and sump pumps may be used to alleviate local
accumulation of ground water.
The invert elevation of the pipe under Pier 80 i s -7.5 feet
and we anticipate a minor amount of groundwater flowing into the
excavations. Under this condition, groundwater control may be
handled by pumps placed at the base of the excavation.
3.6.3 Excavation Base Stability. Stability of the excavation
base w i l l be dependent upon the success of the groundwater
control system, the proximity of the soft younger bay mud to the
excavation base, and the dimensions of the trench. When the
excavation i s i n granular materials, i t i s recommended that the
45
groundwater level be maintained a minimum of two feet beneath
the bottom of the excavation throughout construction in order to
minimize the chance of base failure due to high seepage
gradients.
Basal heave may occur where zones of very soft younger bay
mud are , encountered during construction. A qualified
geotechnical engineer should be consulted at that time for
recommendations on how to improve conditions prior to proceeding
with the excavation.
3.6.4 Pile Driving. Pile driving c r i t e r i a should be determined
by an indicator p i l e program before casting of the production
piles. It i s recommended that piles be driven with followers
prior to excavation to avoid surcharging the excavation. Also i t
may be desirable to p r e d r i l l the piles through the heterogeneous
a r t i f i c i a l f i l l . Both the hammer and the piles should be
supported on fixed leads.
3.6.5 Construction Loads. Significant loads may be imposed on
the pipe during compaction of the trench b a c k f i l l by heavy
equipment. No heavy construction equipment should be allowed to
operate within 2-1/2 feet of the top of the pipe.
3.6.6 Construction Induced Settlements. Caution should be
taken to minimize settlements of the ground surface surrounding
the trench excavation as a result of construction activities
such as excavation, dewatering, and sheetpile driving.
46
It i s recommended that the surrounding structures be
monitored during construction to ensure that construction
activities do not result in detrimental settlements. Should
settlements be observed, a qualified geotechnical engineer
should be consulted for recommendation of appropriate
alternative construction techniques.
3.7 CORROSION
Analysis of s o i l samples taken during this study indicates
that the a r t i f i c i a l f i l l has a pH ranging from 7.2 to 10.0, a
re s i s t i v i t y of 1.5xl0 3 to 2.2xl0 4 ohm centimeters, a sulfate
content of 53 to 160 parts per million (ppm), and a chloride
content of 34 to 2700 ppm. Clay zones within the a r t i f i c i a l f i l l
may exhibit lower r e s i s t i v i t y values than the granular zones.
This information indicates that the a r t i f i c i a l , f i l l may be
moderately corrosive to the buried pipeline. Damage to the pipe
can be prevented by application of a protective coating or by
other protective methods.
\
47
4. QUALITY CONTROL
The conclusions and recommendations presented herein are
based - upon interpretations of subsurface conditions encountered
at the boring locations. Should subsurf ace conditions
encountered during construction d i f f e r from those encountered at
the boring locations, a qualified geotechnical engineer should
review the conclusions and recommendations presented herein for
their applicability and completeness i n li g h t of the new
information.
The placement of pipe bedding and trench b a c k f i l l should be
observed i n the f i e l d by a qualified geotechnical engineer or
his representative. Periodic density tests should be made to
verify that construction i s i n conformance with the
specifications. Also, p i l e driving should be observed and
recorded by a qualified geotechnical engineer. The pile driving
c r i t e r i a should be developed following driving 4 to 5 indicator
pi l e s .
It i s recommended that a qualified geotechnical engineer
review the pipeline design, excavation support system, and
ground water control scheme to determine conformance with the
recommendations presented in this report.
48
5. CLOSURE
This report was prepared i n accordance with generally
accepted geotechnical engineering standards for the exclusive
use of the San Francisco Clean Water Program's Southeast Outfall
System Modifications Project. No warranty i s made as to the
accuracy or completeness of information obtained during previous
investigations by others, and no other warranty i s either
expressed or implied.
Respectfully Submitted,
ALLSTATE GEOTECHNICAL SERVICES
C i v i l Engineer 26084
Rdbert jK Wong ^ /
C i v i l Engineer 20107
49
REFERENCES
Atwater, B.F., CW. Hedel, and E.J. Helley, 1977, "Late Quaternary Depositional History, Holocene Seal-Level Changes, and Vertical Crustal Movement, Southern San Francisco Bay, California," U.S. Geological Survey Professional Paper 1014.
Benjamin, J., and CA. Cornell, 1970, Probability Statistics and Decision for C i v i l Engineers: McGraw H i l l Book Company, New York.
Bonilla, M.G., 1971, "Preliminary Geologic Map of the San Francisco South Quadrangle and Part of the Hunters Point Quadrangle, California, "U.S. Geological Survey, Miscellaneous Field Studies Map MF-311.
Bonilla, M.G., 1964, "Bedrock-Surface Map of San Francisco South Quadrangle, California," San Francisco Bay Region Environment and Resources Planning Study, USGS and HUD, Basic Data Contribution 26.
Borcherdt, R.D., 1975, "Studies for Seismic Zonation of the San Francisco Bay Region," U.S. Geological Survey Professional Paper 941-A.
Brown, R.D., Jr., 1970, "Faults that are Historically Active or that Show Evidence of Geologically Young Surface Displacement," San Francisco Bay Region: U.S. Geological Survey/Housing and Urban Development Basic Data Contribution No.7.
California Division of Mines and Geology, 1972, "Earthquake Intensities, 1810-1969," Seismic Safety Information 72-4.
California Division of Mines and Geology, 1969, "Geologic and Engineering Aspects of San Francisco Bay F i l l s , " Special Report 97.
California Division of Mines and Geology, 1973, "Geologic Map of California, San Francisco Sheet."
California Division of Mines and Geology, 1972, "Preliminary Earthquake Epicenter Map of California, 1934-1971 (June 30)," Seismic Safety Information 72-3.
California Department of Water Resources, 1964, "Earthquake Epicenter and Fault Map of California," Bulletin 116-2.
50
Coats, D.W., 1980, "Recommended Revisions to Nuclear Regulatory Commission Seismic Design Criteria," Lawrence Livermore Laboratory.
Dames and Moore, 1960, "Soil Mechanics Engineering Services, Proposed Port Construction, North Side of Islais Creek and East of Station 15+OOS, San Francisco, California," Report for the San Francisco Port Authority.
Dames and Moore, 1970, "Seismic Stability Studies, Proposed Sand Dike for LASH Terminal F a c i l i t y , San Francisco, California," Report for San Francisco Port Commission.
Dames and Moore, 1982, "Geotechnical Investigation, Army Street Terminal (Pier 80), San Francisco, California," Report for San Francisco Port Commission.
Donovan, N.C. and Valera, J.E., (1972), "A Probabilistic Approach to Seismic Zoning of an Industrial Site," Proceedings of the International Conference on Micro-Zonation for Safer Construction, Research and Application, Seattle, Washington.
Esteva, L., (1970), "Seismic Risk and Seismic Design Decisions," from Seismic Design for Nuclear Power Plants edited by Robert J. Hausen, M.I.T. Press, Cambridge, Massachusetts.
Housner, G.W., (1970), "Strong Ground Motion," from Earthquake Engineering, edited by R.L. Weigel, Prentice Hall, New York.
Greensfelder, R.W., 1974, "Maximum Credible Rock Acceleration from Earthquakes in California," California Division of Mines and Geology.
Kiremidjian, A.S., and H.C. Shah, 1975, "Seismic Hazard Mapping of California," the John A. Blume Earthquake Engineering Center, Stanford University, Report No.21.
Kiremidjian, A.S., and H.C. Shah, 1978, "Seismic Risk analysis for the California State Water Project," The John A. Blume Earthquake Engineering Center, Stanford University, Report No.33.
Lawson, A.C., 1914, "San Francisco Folio," U.S. Geological Survey Atlas Folio 193.
51
Louderback, G.D., 1937, "Characteristics of Active Faults in the Central Coast Ranges of California," Bulletin of the Seismological Society of America, Vol.27.
McGuire, R.K., 1976, "EQRISK: Evaluation of Earthquake Risk to Site," U.S. Geological Survey Open-File Report 76-67.
Schlocker, J., 1970, "Generalized Geologic Map of the San Francisco Bay Region, North California," U.S. Geological Survey Open-File Map.
Schlocker, J., 1974, "Geology of the San Francisco North Quadrangle, California," U.S. Geological Survey Professional Paper 782.
Schnabel, P.B., J. Lysmer and H.B. Seed, 1972, SHAKE, a Computer Program for Earthquake Response Analysis of Horizontally Layered Sites, Report No. EERC 72-12, Earthquake Engineering Research Center, University of California, Berkeley.
Schnabel, P.B. and H.B. Seed, 1972, "Accelerations in Rock for Earthquakes in the Western United States," Report No. 72-2, Earthquake Engineering Research Center, University of California, Berkeley.
Seed, H.B., Idriss, I.M. and Kiefer, R.W. (1969), "Characteristics of Rock Motions During Earthquakes," Journal of the Soil Mechanics and Foundations Division, Proceedings of the American Society of C i v i l Engineers. September.
Seed, H.B., Murarka, R., Lysmer, J. and Idriss, I.M., (1975), "Relationships Between Maximum Acceleration, Maximum Velocity, Distance from Source and Local Site Conditions for Moderately Strong Earthquakes," Earthquake Engineering Research Center, University of California, Berkeley, EERC 75-17.
Seed, H.B. and I.M. Idriss, 1983, "Soil Behavior During Earthquakes," EERI Monograph No. 5.
Seed, H.B., R.T. Wong, I.M. Idriss and K. Tokimatsu, 1984, "Moduli and Damping Factors for Dynamic Analyses of Cohesionless Soils," Report No. EERC 84/14, University of California, Earthquake Engineering Research Center, Berkeley, California.
52
Shah, H.C, et. a l . , (1975), Nicaragua," Part I, The J.A. Center, Report No. 11.
"A Study of Seismic Risk for Blume Earthquake Engineering
Shah, H.C, et. a l . , (1976), "A Study of Seismic Risk for Nicaragua," Part II and Commentary, The J.A. Blume Earthquake Engineering Center, Report No. 12A.
Tocher, D., 1957, "Seismic History of the San Francisco Region; San Francisco Earthquake of March, 1957," California Division of Mines and Geology, Special Report 57.
Trask, P.D., and J.W. Rolston, (1951), "Engineering Geology of San Francisco Bay, California," Bulletin of the Geological Society of America, Vol. 62.
Treasher, R.C, 1963, "Geology of the Sedimentary Deposits in San Francisco Bay, California," California Div. Mines and Geology Spec. Report 82, pp. 11-24.
53
SOUTHEAST OUTFALL SYSTEM MODIFICATIONS
P L A T E 1 .1 - SITE LOCATION MAP
26 TH
IS S
T IS
IS
« o UJ A*
(9
S g LO
UlS
IAr
MA
RY
LAI
DEL
AW
AF
\
ARMY
S.F. PORT AUTHORITY JURISDICTION LINE
_ J ARMY ST. TERMINAL
PROPERTY LINE
TULARE
PIER 80 ( ARMY ST. TERMINAL )
EXISTING 54" EFFLUENT ONSHORE LINE
' a -
a.
4 2 I N C H . DIA. D.I. P I P E
( S L A I S C R E E K i „
U N D E R W A T E R C R O S S I N G S — 1 1 1
STATION 11+00-
DH-3
Y77777777777777777777777777777V77777777777A
K SHED A
N F W C n " F C P I t I F N T I I M P — /
6B3.I3"
3B5.38' 297.75
DIFFUSER SECTION
-EFFLUENT OUTFALL OFFSHORE SECTION - 5 4 INCH DIA DUCTILE IRON PIPE
- 3 6 I N C H D I A . D . L P I P E
-THIRD ST a i t l D K
ISLAIS CREEK
NEW 60" EFFLUENT LINE
4 -CHANNEL
ST.
L E G E N D S C A L E : HUNDRED FEET
DH-2 -A- LOCATION AND DESIGNATION OF
DRILL HOLES BY AGS FOR THIS INVESTIGATION
SEE PLATE 2.3 FOR IDEALIZED SOIL PROFILE FROM STATION 1+00 TO STATION 11+00 ALONG PROPOSED PIPELINE ALIGNMENT.
-A- LOCATION OF DRILL HOLE8 BY T AGS FOR PREVIOUS INVESTIGATION
LOCATION OF DRILL HOLES BY OTHERS
\ \ \ REF: SAN FRANCISCO CLEAN WATER PROGRAM GENERAL LOCATION PLAN DATED 8-12-85
DRILLj H O L E LOCATION MAP
SOUTHEAST OUTFALL SYSTEM MODIFICATIONS
JOB NO. SF61002 PATE: APRIL 1886 PLATE - 1.2
Allstate Geotechnicai Services
P R E - 1 860 SHORELINE
/!
3 0 0 0 6 0 0 0
S C A L E IN F E E T (N)
L
P R O J E C T SITE
PLATE 2.1 PRE- 1 860 SHORELINE MAP A D A P T E D F R O M D O W ( 1 9 7 3 )
I—I I—I I—J S C A L E IN M I L E S
Franciscan assemblage KJt-sandstone and shale
chert, metamorphic rocks, I inn stone, sheared rocks (melange)
KJv - volcanic rocks
Contact Dashed where approximately located.
Sandstone, shale, and conglomerate,- locally in oldest part basaltic volcanic rock and chert
Fault known to be active Dotted where concealed
Fault not known to be active Dotted where concealed. Only selected faults shown. Query Indicates uncertainty as to existence of fault PLATE2^- REGIONAL GEOLOGY AND FAULT MAP
o
N
O
z H
> r- co
o
> I— m
c_
O
03
Z O
to
n
cn
o
o.
ro
> m
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_i
CO
01
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D > H
m
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RA
NC
ISC
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ITY
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M -
E
LE
VA
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(FE
ET
)
CD
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cz
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.
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PROJ! 30 FT
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m
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-62
I
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AIL
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AD
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NC
ISC
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ITY
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(FE
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RELIEVING PLATFORM 0-^
Q O U-
co
f-UJ LU U.
z o
< > UJ _J LL)
- 5 0 H
-100-^
-160
ARTIFICIAL FILL (QAF)
" v H ll Wil «» » ll IS I'
ll |i d iii n\Hi «'i
" U il HII
u u u i l * III! W i 1!"
PIER DECK
RIP RAP
ROCK FILL
SAND DIKE
ARTIFICIAL FILL (QAF)
OLDER BAY MUD (QOB) OLDER BAY MUD (QOB)
-200-J 50
1"=50' 50 5
100
scale feet
PLATE 2.4 - IDEALIZED TRANSVERSE PROFILE - PIER 80 SOUTH DECK
LEGEND
QAF Artificial fill
QYB| Younger bay_mud, soft to firm, highly plastic silty clay
QBS j Bay side sands, poorly graded sand, silt, and clay mixture
PT| Peat and peaty clay, stiff to very stiff, highly plastic
QOB I Older bay mud, stiff to very stiff, moderately to highly plastic sandy and siity clays and clayey sands
Geologic contact
Z Proposed pipeline
DH-2 I Location of exploratory drill I
_L by AGS for this investigation
TB-9
X Location of exploratory boring by others for previous investigations
PLATE 2.5 - LEGEND FOR SOIL PROFILES
L O C A T I O N O F
E P I C E N T E R
O
0
O
o
C O R R E S P O N D I N G
R I C H T E R M A G N I T U D E
2 .5 -3 .4
3 .5 -4 .4
4 .5 -5 .4
5.5-6.4
6 .5 -7 .4
7 .5-8.4
D A T A O B T A I N E D F R O M T H E
UNIVERSITY OF C A L I F O R N I A AT B E R K E L E Y
B 0
I—i i—i i—l: S C A L f c IN M I L E S
Franciscan assemblage KJf-sandstone and shale
chert, metamorphic rocks, limestone, sheared rocks (melange)
KJv - volcanic rocks
Contact Dashed where approximately located.
Sandslone, shale, and conglomerate; locally in oldest part basaltic volcanic rock ond cherl
Fault known to be active Dotted where concealed
Fault not known to be active Dotted where concealed Only selected faults shown Query indicates uncertainty as to existence of fault PLATE 2£r- EARTHQUAKE EPICENTER MAP
0 o.a
2 5 10 50 100 HORIZONTAL DISTANCE FROM SOURCE
OF ENERGY RELEASE*. MILES
AVERAGE VALUES OF MAXIMUM ACCELERATIONS IN ROCK
SOFT TO MEDIUM STIFF CLAY AND SAND
0.1 0.2 0.3 0.4 0.5 0.6 0.7
MAXIMUM ACCELERATIONS IN ROCK
FROM SEED AND IDRISS (1983) APPROXIMATE RELATIONSHIPS BETWEEN
MAXIMUM ACCELERATIONS ON ROCK & OTHER LOCAL SITE CONDITIONS
PLATE 3.1 - EARTHQUAKE ACCELERATION CORRELATIONS
10,000
2
uJ 1000
£E 1-0
0.1 I 1 1 1 1 1 I I 3 4 5 6 7 8 9
RICHTER MAGNITUDE, M
P L A T E 3.2 - E A R T H Q U A K E R E C U R R E N C E C U R V E S
MA
XIM
UM
BE
DR
OC
K A
CC
EL
ER
AT
ION
(G
)
MAXIMUM ACCELERATION (G)
0 0.2 0.4 0.6
240
EQUIVALENT CYCLIC SHEAR STRESS RATIO
240
P L A T E 3 .4 - S I T E R E S P O N S E F O R P R O F I L E 1
P L A T E 3 .5 - S I T E R E S P O N S E F O R P R O F I L E 2
1.00i
2 0.75 Z
o
< DC UJ -I Ul o o < _J
< oc o ui CL CO
0.50
0.25
MAXIMUM CREDIBLE EARTHQUAKE
•2% DAMPING
10% DAMPING
0.00 1 ' 0 1 2 3
PERIOD (SEC)
1.001 T T T
DESIGN EARTHQUAKE
z o i— < oc Ul - J U l o o <
< oc H o Ul a. co
0.75
0.50f-
0.25
0.00
2% DAMPING
10% DAMPING
PERIOD (SEC)
P L A T E 3.6 - R E S P O N S E S P E C T R A A T T H E B A S E O F PIPELINE - PROFILE 1
1.00
o z o
< DC Ul - J UI O O <
-1 < DC f -O ui a co
0.75
0.50
0.25
0.00
DAMPING = 5% PROFILE 1
MAXIMUM CREDIBLE EARTHQUAKE
DESIGN EARTHQUAKE
0.5 1.0 1.5 2.0
PERIOD (SEC)
3.0
1.001
O
z O 0.75]
< DC Ul -1 Ul o o < _i < oc o Ul a. co
0.50
0.25
0.00
DAMPING = 5% PROFILE 2
MAXIMUM CREDIBLE EARTHQUAKE
DESIGN EARTHQUAKE
1.5 2.0
PERIOD (SEC)
P L A T E 3.7 - A T C R E S P O N S E S P E C T R A
BE
ND
ING
M
OM
EN
T
(K-F
T)
25 I
1
1
1
I
I
L
PL
AT
E
3.8
-
BE
ND
ING
M
OM
EN
TS
USE CURVE C FOR DESIGN OF PIPELINES FOR THIS PROJECT
P L A T E 3.9 - E A R T H L O A D C O E F F I C I E N T - Ca
q por unit area
0.2 0.4 0.60.81
Note: m • B/z, n - Uz
m and n are interchangeable
°* - tf.
0.01 0.02 0.04 0.06 0.1 0.2 0.4 C P 1.0 2 4 6 10
P L A T E 3 .10 - V E R T I C A L S U R C H A R G E P R E S S U R E S
P L A T E 3.11 - L A T E R A L S U R C H A R G E P R E S S U R E S
GROUND SURFACE-^
2q u- 0
A
eCH 1+H 2) 1
BOTTOM OF EXCAVATION
r I U N * N
V \
Younger Bay Mud (Qyb)
Artificial Fill (Qaf)
non-i 'I 21Hj|'63rl2'l'
H i
o a
D M
Q
NOTES
1) Hi,H2,Do are to be in feet. Pressures are in pounds per square foot.
2) v ^mH1+&>H2 ^ m = 1 2 0 P c f (""it weight of fill above water table) Ce= + , l$fo= 63 pcf (unit weight of fill below water table)
1 2 qu=600 psf (unconfined compression strength of Qyb)
3) Safety factor to be included by designer.
P L A T E 3 .12 - P R E S S U R E DISTRIBUTIOM F O R C A N T I L E V E R E D S H E E T PILE - SIMPLIFIED M E T H O D
APPENDIX A
SUPPORTING GEOTECHNICAL DATA
EXPLORATION
Exploration for this investigation was performed from March
31, 1986 through April 3, 1986, and consisted of d r i l l i n g of 5
d r i l l holes, DH-1 through DH-5. The d r i l l holes ranged in depth
from 17-1/2 feet to 146 feet with a total aggregate depth of
398-1/2 feet. The locations of the d r i l l holes are shown on
Plate 1.2 - D r i l l Hole Location Map. A Failing 750 rotary wash
r i g , provided by Pitcher D r i l l i n g Company of Palo Alto,
California, was used. Both casing and d r i l l e r ' s mud were used in
advancing the d r i l l holes.
The soils encountered were logged continuously in the f i e l d
by an engineer during d r i l l i n g operations. The soils were logged
using the Unified Soil Classification System. Logs of borings
presented on Plates A - l . l through A-1.14 give descriptions of
the earth materials encountered, show a graphic representation
of the s o i l profile found, give the depth at which s o i l samples
were obtained, indicate water levels, i f encountered, and f i e l d
and laboratory tests performed. A legend to the logs i s
presented on Plate A-2. D r i l l hole locations at the Southeast
Outfall System Modifications site were determined by tape
measurements from known points along the alignment. The location
of the d r i l l holes should be considered accurate only to the
degree implied by the method used. Ground surface elevations at
the d r i l l hole locations were determined using a pr o f i l e drawing
of the ground surface along the alignment supplied by the San
Francisco Clean Water Program.
A-1
SAMPLING
Three different types of samplers were u t i l i z e d for s o i l
sampling in this investigation which are tabulated below:
Sampler Method of Advance Sample Dimension
Standard Spl i t Spoon Driven by 140-pound
(2" O.D.) or Standard hammer f a l l i n g
Penetration Test
Sampler
30 inches
1-3/8-inch diameter
x 18 inches
Spli t Spoon
Sample Barrel
(3" O.D.) or
Modified California
Sampler
Driven by 400-pound
hammer f a l l i n g
18 inches
2.4-inch diameter
x 18 inches
Thin-Wall Shelby
Tube Sampler
Pushed into the s o i l . 2.8-inch diameter
Sampler head contains x 30 inches
ba l l check to prevent
water pressure from
forcing the sample
out of tube during
withdrawal.
A-2
The samples were obtained generally by using the Standard
Penetration Test Sampler and the Modified California Sampler on
the f i l l , the bay side sands, and the older bay mud. The Shelby
Tube Sampler was used in the younger bay mud.
LABORATORY TESTING
Laboratory tests were performed on representative s o i l
samples in order to define the engineering properties of the
various earth materials. Testing procedures followed accepted
practice where possible. Where ASTM Standards were used, the
latest edition or revision for each test procedure was employed.
MOISTURE CONTENT AND DENSITY TESTS
Moisture content tests were performed on 38 samples. The
moisture content was determined in accordance with ASTM D2216,
Standard Method for Laboratory Determination of Water (Moisture)
Content of S o i l , Rock, and Soil-Aggregate Mixtures. Density
determinations were performed on 13 undisturbed samples. The
results of the moisture and density tests are presented on the
d r i l l hole logs.
CONSOLIDATION TEST
A one-dimensional consolidation test was performed on 1
selected undisturbed sample i n accordance with Standard Test
Method ASTM D2435-Standard Test Method for One Dimensional
Consolidation Properties of Soils.
A-3
The test sample was 1.0 inches i n height and 2.875 inches i n
diameter. Loads were applied to the samples by the use of air
pressure regulators feeding into the consolidometers. Accuracy
was maintained throughout the loading range by the use of
sensitive o i l and mercury manometers for the lower loads and psi
gauges for the higher loads. Sample deformation was measured to
0.0001 inch. The sample was allowed to consolidate for
approximately 24 hours under each load increment. Time readings
were taken at selected loads. Rebounding was done at twice the
rate of loading and the f i n a l specimen data was calculated at
the last rebound increment. Results of the condolidation test,
in the form of consolidation versus log of pressure, i s
presented on Plate A-3. Time readings, in the form of d i a l
readings versus log of time, are presented on Plate A-4.
UNCONFINED COMPRESSION TESTS
Unconfined compression tests were performed on 2 undisturbed
samples of younger bay mud. The tests were run in accordance
with Standard Test Method ASTM D2166-Standard Test Method for
Unconfined Compression Strength of Cohesive S o i l .
Prior to testing, the specimen's dimensions were measured
and recorded. The tests were performed at f i e l d moisture
conditions. During the tests, the late r a l l y unsupported
cylindrical specimens were subjected to a gradually increased
axial compression load at a rate of strain of 2 percent per
minute u n t i l failure occurred. Displacements and their
corresponding loads were measured and recorded throughout the
tests. Results of the unconfined compression tests are presented
on Plates A-5.1 and A-5.2.
SIEVE ANALYSIS TESTS
Five wash sieve analysis tests were performed on the
obtained samples to assist i n the cl a s s i f i c a t i o n of subsurface
soils and determination of the liquefaction potential. The tests
were performed in accordance with ASTM D422. The results of the
wash tests are shown" on the d r i l l hole logs.
TORVANE SHEAR STRENGTH TESTS
Torvane shear strength tests were performed on 18
undisturbed cohesive s o i l samples. The test results are-
presented on the d r i l l hole logs.
CHEMICAL TESTS
In order to evaluate the potential corrosiveness of the
a r t i f i c i a l f i l l , two samples were submitted for chemical tests.
The results of these tests are presented i n Table A-1 - Chemical
Tests.
TABLE A-1
CHEMICAL TESTS
Boring Depth
(feet)
Soil
Type
PH
at 25°c Resistivity
(ohm-cm)
Sulphate
S0 4
(mg/kg)
Chloride
Cl
(mg/kg)
5 SP 7.2
15 SM 10.1
1500
22000
160
53
34
2700
A-5
LOG OF DRILL HOLE
PROJECT: Southeast Outfall LOGGED B Y : C S
DRILL HOLE N O . : DH-1 CHECKED B Y : C L DRILLING METHOD: Rotary Wash DRILLING DATE: 3/31/86
R E F E R E N C E E L . : H ft. (Approx D A T U M : San Francisco
City Datum (SFCD)
L3i
O
Ul Ul CL - i f
d
z Ui u i _ i _) o_ O.
S < < CO CO
-13*
20
1-23*
L 301
-331.
\ CO \-z O o * o _1 CD
CD O
O I
< DT
GEOTECHNICAL DESCRIPTION
AND CLASSIFICATION
" ARTIFICIAL FILL (Qaf) 11
SAND (SP), gray-brown, fine-grained PEAT (Pt) lens at 2* to 3 feet
" ARTIFICIAL FILL (Qaf) " [_ GRAVELLY SAND (SP), with silt, glass, J L a n d brick fragments, dark gray to gray-brown,
very loose to loose, medium-grained 3/31|nterbedded with SILTY CLAY (CH) at 5 ft. /86
" ARTIFICIAL FILL (Qaf) " GRAVEL AND COBBLES mixed with SILTY CLAY (CH), with glass and br icks, soft, high plasticity
" ARTIFICIAL FILL (Qaf) " SILTY SAND (SM), with organics, black, very loose to loose (23.4% Passing No. 20ft Sieve)
Chunk of wood at 19* ft. Gravel, wood, and bricks in cuttings (No recovery on split spoon samples)
" YOUNGER BAY MUD (Qyb) " SILTY CLAY (CH), gray, very soft to soft, high plasticity
TORVANE = 400 psf
co z Iii Q u _ > o c e o . Q —•
cr" U l ~
* Z
52z O o 2 O
52
80
3 O
£
o I-w <
< z o E J 2 o c o o u i
GS
TV
S H E E T 1 OF 4 P L A T E A - 1.1
LOG OF DRILL HOLE
PROJECT: Southeast Outfall LOGGED B Y : CS D R I L L H O L E NO. : DH-1 CHECKED B Y : CL DRILLING METHOD: Rotary Wash DRILLING DATE: 3/31/86
R E F E R E N C E E L . : DATUM: SFCD
1* ft. (Approx
UJ Q_
CO I-Z
O
o o -J tn
o
GEOTECHNICAL DESCRIPTION
AND CLASSIFICATION
t eo z u _ °u. >• o CC Q_
52z o 0 £ o
5
3 O
h s _i u 0)
<
O
E " Q CO a u i
<i~
35 " YOUNGER BAY MUD (Qyb) " SILTY CLAY (CH), gray, soft to firm, high plasticity
-38*
45
TORVANE = 320 psf 59 TV
-48*
55
-58*
65
65 59 CN
•68*
S H E E T 2 OF 4 P L A T E A - 1.2
LOG OF DRILL HOLE
PROJECT: Southeast Outfall LOGGED B Y : CS D R I L L H O L E NO.: DH-1 CHECKED B Y : CL DRILLING METHOD: Rotary Wash DRILLING DATE: 3/31/86
R E F E R E N C E E L . : i* ft. (Approx DATUM: SFCD
\ CO I-z Z> o o
S o _ l ca
GEOTECHNICAL DESCRIPTION
AND CLASSIFICATION to z
> u CCD. Q —
U J .
« Z
o o 5 O
- J
Q
3
a
9
< a_
-j < z o
E f 2 oto O U J
70 " YOUNGER BAY MUD (Qyb) " SILTY CLAY (CH), gray, firm, high plasticity
b 7 3 i J
80
•83*
TORVANE = 560 psf 53 TV
90
b93f
100
" YOUNGER BAY MUD (Qyb) " SANDY PEAT (Pt), dark brown, stiff, high plasticity
103* " BAY SIDE SAND (Qbs) "
S H E E T 3 OF n P L A T E A - 1-3
LOG OF DRILL HOLE
PROJECT: Southeast Outfall LOGGED B Y : CS DRILL HOLE NO. : DH-1 CHECKED B Y : C L DRILLING METHOD: Rotary Wash DRILLING DATE: 3/31/86
R E F E R E N C E E L . : 1* ft. [Approx D A T U M : SFCD
z o
5 H H
CQ
GEOTECHNICAL DESCRIPTION
AND CLASSIFICATION
H
CO
z UJ _
> o cr o. Q
LU CC
— H O O 5 O
o Z>
o
o r-co < CL
< z o Ei° oto O U I
105 17
,108*J
115
„ t i M 78
125
-128iJ
L
" BAY SIDE SANDS (Qbs) " C L A Y E Y SAND (SC) , gray-green, dense, fine to medium-grained
SANDY C L A Y (CH) , green-gray, very stiff, high plasticity at 104* to 106* feet
TORVANE = 2200 psf on SILTY CLAY (CH) at 105 feet
95 28 TV
Less clay content and color change to gray-brown at 120* feet (5.1% Passing No. 200 Sieve) 108 19 GS
Bottom of boring at 121 feet below the ground surface at approximately elevation -119* feet (SFCD)
S H E E T 4 OF 4 P L A T E A - 1-4
LOG OF DRILL HOLE
PROJECT: Southeast Outfall LOGGED B Y : CS D R I L L H O L E N O . : DH-2 CHECKED B Y : CL R E F E R E N C E E L . : - 3 ft. (Approx DRILLING METHOD: Rotary Wash DRILLING DATE: 4/1/86 D A T U M : SFCD
z
o
I U 3 . Q
ci z
LU LU - J _ i CL CL 2 2
< < CO CO
H LU "S. CO I— z Z> o
o
-J CO
CD o _1
o X 0. < tr CD
GEOTECHNICAL DESCRIPTION
AND CLASSIFICATION CO z UJ _ Q u _ > o orcL
L U .
* Z
H g 2 z o o 2 u
2
ZD O
cr*
O
CO <
< z o E H Q CO Q LU
-8
20
-28
30
-38
11 ARTIFICIAL FILL (Qaf) " CLAYEY SAND (SC), with gravel, brown, fine to medium-grained Color change to gray and oil odor at 3 ft. 14
" ARTIFICIAL FILL (Qaf) " Tgg SANDY GRAVEL (CP), with clay and
oil odor, loose SILTY CLAY (CH), gray, firm at 5*-6 ft.
" ARTIFICIAL FILL (Qaf) 11
SILTY SAND (SM), with gravel and wood, black, loose, fine-grained
(25.4% Passing No. 200 Sieve)
40 GS
Brick and wood in cuttings
" YOUNGER BAY MUD (Qyb) " PEAT (Pt), dark brown, stiff, high plasticity with SILTY SAND (SM) lenses
P55
" YOUNGER BAY MUD (Qyb) " SILTY CLAY (CH),,with shells, gray, soft, high plasticity TORVANE = 470 psf
65 TV
Bottom of boring at 27* feet below the |_ ground surface at approximately
elevation -30* feet (SFCD)
S H E E T 1 OF 1 P L A T E A - 1.5
LOG OF DRILL HOLE
PROJECT: Southeast Outfall LOGGED B Y : CS DRILL HOLE N O . : D H " 3 CHECKED B Y : C L R E F E R E N C E E L . : -2* ft. (Approx DRILLING METHOD: R o t a r Y W a s h DRILLING DATE: 4/1-2/86 D A T U M : SFCD
z 2
U J 3 - 0
o fz LU _ J CL
£
< CO
u. v. CO f-z
o o
o _ J CO
CD O
O
X CL < CC CD
GEOTECHNICAL DESCRIPTION
AND CLASSIFICATION
>•
H
CO
z uJ _ Q L _ > O CCCL O —
U J .
H g
12z O o £ o
o
o 1-co <
o
Q CO O U l
" ARTIFICIAL FILL (Qaf) » CLAYEY SAND (SC), with gravel, fine to coarse grained 5 inches asphaltic concrete at surface
L7* " ARTIFICIAL FILL (Qaf) "
.X.SAND (SP), brown, medium dense.
27 H/\ fine to medium-grained /36 Saturated below 5 ft.
19
L 10.
Ll7f
20
L27*
30
L371
» ARTIFICIAL FILL (Qaf) " SILTY SAND (SM), with peat lenses, black, very loose, fine-grained (6.6% Passing No. 200 Sieve) Mixed with sTlty clay, shells, and peat 12 to 15 feet
29 GS
" YOUNGER BAY MUD (Qyb) " SILTY CLAY (CH), with shells, gray, soft, high plasticity
TORVANE = 330 psf
63 61 TV,| IUC
S H E E T 1 OF 5 P L A T E A - 1.6
LOG OFDRILL HOLE
PROJECT: Southeast Outfall LOGGED BY- c s
D R I L L H O L E N O . : Drl-3 CHECKED B Y : C L R E F E R E N C E E L . : -2* ft. (Approx DRILLING METHOD: Rotary Wash DRILLING DATE: 4/1-2/86 DATUM: SFCD
O
L U 3 . Q
GEOTECHNICAL DESCRIPTION
AND CLASSIFICATION
t CO z UJ _ Q u _ >-u C C Q . o -—
z
U l I-z o u
CT'
t 5 - J
a
o
£T 5 _i
O
I-eo <
E f 2 a co a UJ < * -
35
•42*
L 4*1
J~52*.
55
65
72*
" YOUNGER BAY MUD (Qyb) " SILTY CLAY (CH), gray, soft, high plasticity
TORVANE = 430 psf
Grading to very soft at 55 ft.
TORVANE = 200 psf
90 TV
70 TV
S H E E T 2 OF 5 P L A T E A - 1.7
LOG OF DRILL HOLE
PROJECT: Southeast Outfall LOGGED BY* c s
DRILL HOLE N O . : DH-3 CHECKED BY: C L R E F E R E N C E E L . : -2* ft.(Appro: DRILLING METHOD: Rotary Wash DRILLING DATE: 4/1-2/86 D A T U M : SFCD
ILU I
co
GEOTECHNICAL DESCRIPTION
AND CLASSIFICATION to z UJ _ o
>-o oro. Q
UJ or
= u i to O o S o
2
3 o
t 2 _J CJ
(-to <
CL
< z o E{2 o to O LU < I-
70
U77*
" YOUNGER BAY MUD (Qyb) 11
SILTY CLAY (CH) , gray, firm, high plasticity
TORVANE = 520 psf 69 TV
b B 7 i J
TORVANE = 700 psf 58 TV
L io^
-107*
S H E E T 3 OF 5 P L A T E A - 1.8
LOG OF DRILL HOLE
PROJECT: Southeast Outfall LOGGED B Y : CS D R I L L H O L E N O . : DH-3 CHECKED B Y : CL R E F E R E N C E E L . :-2* ft. (Approx DRILLING METHOD: Rotary Wash DRILLING DATE: 4/1-2/86 DA TUM: SFCD
UJ 3 - O
U.
CO I-z 3 o o
S o _ l CO
CD O
o X a. < cc CD
GEOTECHNICAL DESCRIPTION
AND CLASSIFICATION
> H
CO
z UJ _ > o C C D .
LU CC
" g £ z O o s o
cr*
o
cr*
O
f -CO < _I 0.
< z o
E{2 O CO O U I
<ti-
105
- i m
;122i.
125
bl32iJ
135
id
142*
V7,
14
46
/ / A
Y/A
/ / A
v« v«
V*
4
11 YOUNGER BAY MUD (Qyb) " SILTY CLAY (CH), gray, firm, high plasticity
" YOUNGER BAY MUD (Qyb) " PEATY CLAY (OH), dark brown to black, stiff , high plasticity
TORVANE = 1340 psf
Interbedded PEATY CLAY (OH) and CLAYEY SAND (SC) from 120 feet to 136 feet
54 75 TV
TORVANE = 1740 psf 82 38 TV
Increased sand content at 131 to 135 feet
PEATY CLAY (OH) with sand lens at 135 to 136 feet
" BAY SIDE SANDS (Qbs) " SILTY SAND (SM), green-brown, dense, fine-grained
79
1107 41 20
S H E E T 4 OF 5 P L A T E A - 1.9
LOG OF DRILL HOLE
PROJECT: Southeast Outfall LOGGED B Y : CS DRILL HOLE N O . : DH-3 CHECKED B Y : C L DRILLING METHOD: Rotary Wash DRILLING DATE: 4/1-2/86
R E F E R E N C E E L . : D A T U M : SFCD
•2* ft. (Approx)
UJ3- o
I-u .
CO \~ z 3 o u
o m
CD o _j o x Q_ < ce CD
GEOTECHNICAL DESCRIPTION
AND CLASSIFICATION
>-H CO z UJ _
ceo. Q —-
UJ ,
^ g 52z go S o
o 3 O
t 2 _ l
o H (0
< CL
O
O CO O U I
140 " BAY SIDE SANDS (Qbs) " GRAVELLY SAND (SP), with clay, green-gray, very dense, interbedded with CLAYEY SAND (SC), dark brown, very dense, fine-grained
150
90 10'
11
Bottom of boring at 146 feet below the ground surface at approximately elevation -1481 feet (SFCD)
S H E E T 5 OF 5 P L A T E A - 1.10
LOG OF DRILL HOLE
PROJECT- Southeast Outfall LOGGED B Y : CS D R I L L H O L E NO. : D H ^ CHECKED B Y : C L R E F E R E N C E EL.: -2 ft . (Approx) DRILLING METHOD: Rotary Wash DRILLING DATE: 4/2/86 D A T U M : SFCD
H' U. •v. 5
EL
EV
AT
ION
(F
EE
T)
DE
PT
H
SA
MP
LE
S
AM
PL
E N
O.
BLO
W C
OU
NT
S^
GR
AP
HIC
LO
G
GEOTECHNICAL DESCRIPTION
AND CLASSIFICATION
DR
Y D
EN
SIT
Y
(PC
F)
MO
IST
UR
E
CO
NT
EN
T
(%)
LIQ
UID
LIM
IT (
'
PL
AS
TIC
LIM
IT i
AD
DIT
ION
AL
T
ES
TS
0 " ARTIFICIAL FILL (Qaf) " CLAYEY SAND (SC), with gravel, fine to coarse-grained 5 inches asphaltic concrete at surface
-7 _
i • 31
" ARTIFICIAL FILL (Qaf) 11
SAND (SP), brown, dense, -fine to medium-grained 8
-
1(f
" YOUNGER BAY MUD (Qyb) " CLAYEY SILT (OH), with organics and sand
-• 2 1
» YOUNGER BAY MUD (Qyb) ." SILTY CLAY (CH), interbedded with organic CLAYEY SILT (OH), soft, high plasticity
49 85 T V , UC
-17
• 3 I - TORVANE = 300 psf
Extensive shells at 17 feet 61
—
L 2 ( L Bottom of boring at 17* feet below the ground surface at approximately elevation -19* feet (SFCD)
Z 27 —
- - — - —
S H E E T 1 OF 1 P L A T E A - 1.11
LOG OF DRILL HOLE
PROJECT: Southeast Outfall LOGGED B Y : CS DRILL HOLE N O . : DH-5 CHECKED BY : CL DRILLING METHOD: Rotary Wash DRILLING D A T E : 4/2-3/86
R E F E R E N C E E L . : Oft. (Approx) DATUM: SFCD
52
- a s U J 3 Q
u-\ CO \— z 3 O o
s o _ l CO
CD o -I
o X Q.
< or CD
GEOTECHNICAL DESCRIPTION
AND CLASSIFICATION
>-CO z UJ _
>• o C C O . Q — i
UJ
cc
<2z o o z o
3 O
o
CO
< z o
E{2 Q CO O U J
1 Q M
-15
20
-25
L 30J
" ARTIFICIAL FILL (Qaf) " SAND (SP), brown, fine-grained, loose Chunk of clay at 3 feet
" ARTIFICIAL FILL (Qaf) " CLAYEY SAND (SC), with gravel, shells and brick fragments, gray-brown and brown, very loose to loose, fine to medium-grained Saturated below 8 feet
(24.1% Passing No. 200 Sieve) Extensive gravel and color change to gray-brown and black at 10 feet
" YOUNGER BAY MUD (Qyb) " SILTY CLAY (CH), with shells and some organics, dark gray, soft to firm, high plasticity
TORVANE = 500 psf
Organic odor at 25 feet TORVANE = 430 psf
63
10
16 GS
16
60 TV
88 TV
S H E E T 1 OF 3 P L A T E A-1.12
LOG OF DRILL HOLE
PROJECT: Southeast Outfall LOGGED B Y : c s
D R I L L H O L E N O . : D H " 5 CHECKED B Y : C L R E F E R E N C E E L . : o ft. (Approx) DRILLING METHOD: Rotary Wash DRILLING DATE: 4/2-3/86 D A TUM: SFCD
111 U I 3 - Q
U l _ l Q_
< to
o Iz U l _J CL
s < to m
GEOTECHNICAL DESCRIPTION
AND CLASSIFICATION
t to z UJ _ Qu_ >u t C C L Q -—
_ l
Q
O
o I-to <
< z o
to f Z I— o to Q UJ
<»-35
ko
" YOUNGER BAY MUD (Qyb) " SILTY CLAY (CH), gray, soft to firm, high plasticity
TORVANE = 500 psf
L at TORVANE = 500 psf
•50
55
•60
" BAY SIDE SANDS (Qbs) " CLAYEY SAND (SC), gray, dense to very dense, fine-grained
Decreased clay content (SP-SC) and fine to medium-grained at 65 feet
r-70
59 TV
63 TV
15
118 18
S H E E T 2 OF 3 P L A T E A - 1.13
LOG OF DRILL HOLE
PROJECT: Southeast Outfall LOGGED B Y : CS DRILL HOLE NO. : DH-5 CHECKED B Y : CL R E F E R E N C E E L . : Oft.(Approx) DRILLING METHOD: Rotary Wash DRILLING DATE: 4/2-3/86 D A T U M : SFCD
z o
U 1 3 Q
U i - J CU S
< CO
LU
< CO
u.
CO
z z> o o
o - J CQ
CD O - J
o X
cu < cc CD
GEOTECHNICAL DESCRIPTION
AND CLASSIFICATION
H CO
z
> o CCCL a ~ i
ui cc
" g
<2z O o S o
H 2 _l
o z> a
cr-
2 _I
o H CO < _l CL
o E J 2 O CO out
70
-75 id 80
9"
" BAY SIDE SAND (Qbs) " CLAYEY SAND (SP-SC), gray, very dense, fine to medium-grained
SAND (SP), brown, fine-grained, very dense at 75 feet
111 21
80
" OLDER BAY MUD (Qob) " SILTY CLAY (CH) , gray-green, stiff, moderate to high plasticity
-85
hi 10 TORVANE = 1700 psf 64 62 TV
9QJ
Bottom of boring at 86* feet below the ground surface at approximately elevation -86* feet (SFCD)
-95
S H E E T 3 OF 3 P L A T E A-1.14
I 1
I i
r~i
CT
C
T
CT
CT
?
EC
T C
T
LC
T E
CT
CT
CC
T
CT
L
CT
CT
C
CT
CT
Fine
-gra
ined
sai
ls
(Mo
re t
hin
hal
f m
ater
ial
it s
mal
ler
than
No
. 200
sie
ve)
Coa
rse-
grai
ned
toils
(M
ora
than
hal
t o
l m
ater
ial Ii
larg
er t
han
No
. 200
sfa
ve s
ize)
Hig
hly
orga
nic
•oil*
Sil
ti a
nd c
layi
(L
iqu
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N O T E : Consolidation curves are for 24 hour load increments
HOLE HQ.
SAMPLE NO.
DEPTH ( f t )
INITIAL SPECIMEN DATA
DRY DENSITY
WATER CONTENT
VOID RATIO
FINAL SPECIMEN DATA
DRY DENSITY
WATER CONTENT
DE6REE OF SATURATION
£S)
1-6 65 65.3 58.8 1.676 77.8 44.5 100
Southeast Outfall System Modifications San Francisco, California
CONSOLIDATION TEST Southeast Outfall System Modifications San Francisco, California
P R O I E C T N O . D A T E F I G U R E H O .
Southeast Outfall System Modifications San Francisco, California
SF510O2 MAY 1986 A-3
0.1 1.0 10 100 1000 10,000
TIME, B i n u t i s • -
KEY
(7) 2000-1,000 psf Boring: : DH-1
(2) 4000-8000 psf Sample No : 1-6
Sample Depth : 65 ft.
Southeast Outfall System Modifications San Francisco, California
CONSOLIDATION TEST TIME - COMPRESSION CURVES
Southeast Outfall System Modifications San Francisco, California
P S 0 J E C T H O . D A T E f t S U R E N D .
Sr-51002 MAY 198(3 A-4
800
AXIAL STRAIN. %
Southeast Outfall System Modifications San Francisco, California
UNCQNFINED COMPRESSION TEST
P R O J E C T M O . O I T t
SF51QQ2 F I G U R E N O .
A-5.1
TO]
AXIAL STRAIN, %
Southeast Outfall System Modifications UNCQNFINED COMPRESSION TEST
San Francisco, California P R O J E C T MO. O t T E F I G U R E H Q .
SF31602 MAY 1986 A-5 .2
APPENDIX B
SOIL CONTAMINATION TESTS
During our f i e l d i n v e s t i g a t i o n , the s o i l s encountered i n
d r i l l hole DH-2 at approximately 3 to 8 feet below the ground
surface had on " o i l y " appearance and odor. Samples of these
s o i l s were taken to a chemical t e s t i n g laboratory to determine
i f they contained hazardous substances. A gas
chromatography/mass spectrometry (GC/MS) t e s t f o r semi-volatile
compounds (U.S. EPA Method 8270) was performed on a drive sample
and an o i l and grease analyses was performed on a bag sample.
The r e s u l t s of the GC/MS te s t f or semi-volatiles are shown on
Plate B-1. The r e s u l t s indicate that the s o i l does not contain
p r i o r i t y or non-priority pollutant compounds i n excess of the
l i m i t s determined by the EPA. However, the o i l and grease
analyses showed that the s o i l materials at a depth of 6 to 7
feet contained 870 mg/kg of o i l and grease.
The EPA does not have s p e c i f i c upper l i m i t s f o r the amount
of o i l and grease a s o i l may contain. However, the presence of
o i l and grease may indicate that the s o i l contains v o l a t i l e
p r i o r i t y p o l lutant compounds and/or the s o i l may have a
flashpoint below the upper l i m i t determined by the EPA.
Specialized sampling and storage equipment i s needed to obtain
s o i l samples f o r laboratory analyses for v o l a t i l e compounds and
flashpoint t e s t i n g . Since t h i s equipment was not available at
the time d r i l l hole DH-2 was d r i l l e d , the s o i l samples taken
were not sampled or stored adequately and t e s t s f or v o l a t i l e
compounds and flashpoint were not performed.
B-1
In conclusion, the s o i l encountered i n d r i l l hole DH-2
contains o i l and grease but does not contain semi-volatile
pollutants above the l i m i t s determined by the EPA. However, due
to the u n a v a i l a b i l i t y of sampling and storage equipment during
d r i l l i n g , i t has not been determined i f the s o i l contains
v o l a t i l e pollutant compounds or has a flashpoint below the upper
l i m i t determined by the EPA. Recommendations for further study
are contained i n our proposal to the San Francisco Clean Water
Program dated June 11, 1986.
B-2
GC/MS P r i o r i t y P o l l u t a n t A n a l y s i s Kennedy/Jenks/Chilton, Laboratory D i v i s i o n 657 Howard Street San F r a n c i s c o , CA 94105 415-362-6065
For A l l s t a t e Geotechnical Services A t t e n t i o n C r a i g S. S h i e l d , A s s o c i a t e Received 4/17/86 Address World Trade Center, Suite 258 Reported 5/12/86
Page 2 of 2
Lab.No. 862106 Date C o l l e c t e d - C o l l e c t e d by A l l s t a t e Geotechnical S e r v i c e s
Source S.E. O u t f a l l Time C o l l e c t e d - Sample Type: Sediment: DH-2 5 f t SF51002
PRIORITY POLLUTANT COMPOUNDS COMPOUNDS mg/kg(ppm) COMPOUNDS mg/kg(ppm)
phenol <0.5 2 , 6 - d i n i t r o t o l u e n e <0.5
2-chlorophenol <0.'5 acenaphthene <0.5
2- n i t r o p h e n o l <0.5 2 , 4 - d i n i t r o t o l u e n e <0.5 2,4—dimethylphenol <0.5 f l u o r e n e <0.5
2,4-dichlorophenol <0.5 d i e t h y l p h t h a l a t e <0.5 4-chloro-3 —methy1pheno1 <0.5 4-chlorophenylphenyl ether <0.5
2 , 4 , 6 - t r i c h l o r o p h e n o l <0.5 N-ni t r o s od iphenylamine <0.5 2, 4 - d i n i t r o p h e n o l <2.5 1,2-diphenylhydrazine (azobenzene) <0.5
2-methyl-4,6-dinitrophenol <2.5 4—bromophenylphenyl ether <0.5 4-nitro p h e n o l <0.5 hexachlorobenzene <0.5 pentachlorophenol <0.5 phenanthrene <0.5 b i s ( 2 — c h l o r o e t h y l ) e t h e r <0.5 anthracene <0.5 1,3-dichlorobenzene <0.5 ' d i - n - b u t y l p h t h a l a t e <0.5 1,4-dichlorobenzene <0.5 fluor a n t h e n e <0.5
1,2-dichlorobenzene <0.5 be n z i d i n e <2-5
b i s ( 2 - c h l o r o i s o p r o p y l ) e t h e r <0.5 pyrene <0.5
hexachloroethane <0.5 ben z y l b u t y l p h t h a l a t e <0.5 N-nitrosodi-n-propylamine <0.5 benz[a]anthracene <0.5
nitrobenzene <0.5 3, 3 ' - d i c h l o r o b e n z i d i n e <1
isophorone <0.5 chrysene <0.5
b i s ( 2 - c h l o r o e t h o x y ) methane <0.5 b i s ( 2 - e t h y l h e x y 1 ) p h t h a l a t e 0.6
1,2,4-trichlorobenzene <0.5 d i - n - o c t y l p h t h a l a t e <0.5
naphthalene <0.5 benzof b ] f l u o r a n t h e n e <0.5
hexachlorobutadiene <0.5 benzo[k]fluoranthene <0.5 hexachlorocyclopentadiene <0.5 benzo[a]pyrene <0.5
2-chloronaphthalene <0.5 indeno[1,2,3-cd]pyrene <0.5 dimethyl p h t h a l a t e <0.5 dib e n z [ a ,h]anthracene <0.5 acenapbthylene <0.5 benzo[ghi]perylene <0.5
NON—PRIORITY POLLUTANT COMPOUNDS benzoic a c i d <5 4 — c h l o r o a n i l i n e <2-5 2-methylphenol <0.5 2-methylnaphthalene <0.5 4-methylphenol <0.5 2 - n i t r o a n i l i n e <2.5 2, 4 , 5 - t r i c h l o r o p h e n o l <0.5 3 - n i t r o a n i l i n e <2.5 a n i l i n e <0.5 dibenzofuran <0.5 benz y l a l c o h o l <1 4 — n i t r o a n i l i n e <2.5
A n a l y s i s by U.S. EPA Method 8270, reported i n m i l l i g r a m s per ki l o g r a m , wet (as recei v e d ) we.ight b a s i s .
A n a l y s t JW Manager
Tnis r e p o r t appiies o n l y to t n e s a m o i e m v e B i i g a t e a a n d J S n o t n e c e s s a r i l y i n d i c a t i v e o f t h e q u a l i t y of a o c a r e n t l y i d e n t i c a l o r s i m i t a r s a m o l e s . The liabilit y of tne l a b o r a t o r y is l i m i t e d to t n e a m o u n t p a d far t n e r e p o r t by the issuee. The i s s u e e a s s u m e s all l a b i l i t y t o r t h e f u r t h e r d i s t r i D u t i o n of this r e p o r t
or i t s c o n t e n t s a n d b y m a k i n g s u c n a i s t n o u i i G r ; a g r e e s to hoid t h e l a b o r a i o r y h a r m l e s s a g a i n s t all c l a i m s of p e r s o n s s o i n f o r m e d of t h e c o n t e n t s
h e r e o f .
Recommended