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

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RELIEVING PLATFORM 0-^

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z o

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- 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

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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 .