HomeMy WebLinkAbout3182 | 3528; Vista/Carlsbad Interceptor Sewer/ S CV Storm Drain; Vista/Carlsbad Inter Sewer/ S CV Storm Drain Pt 1; 1998-01-30REPORT
GEOTECHNICAL INVESTIGATION
VISTA/CARLSBAD
INTERCEPTOR SEWER
REPLACEMENT AND
SOUTH CARLSBAD VILLAGE
STORM DRAIN PROJECTS
CARLSBAD, CALIFORNIA
Prepared/or
Carlsbad Municipal Water District
5950 El Camino Real
Carlsbad, CA 92008
CMWD Project No. 91-403
City of Carlsbad Project No. 3538
Woodward-Clyde Project No. 97.51028A-0007
January 30, 1998
Woodward-Clyde
Pacific Center II, Suite 1000
1615 Murray Canyon Road
San Diego, CA 92108-4314
619-294-9400 Fax: 619-293-7920
n
Woodward-Clyde
Engineering & sciences applied to the earth & its environment
January 30, 1998
Ms. Kelly J.Efimoff,P.E.
Carlsbad Municipal Water District
5950 El Camino Real
Carlsbad, CA 92008
Subject: Geotechnical Investigation
Vista/Carlsbad Interceptor Sewer Replacement Project
and South Carlsbad Village Storm Drain Project
Carlsbad, California
(CMWD Project No. 91-403 and City Project No. 3538)
Woodward-Clyde Project No. 9751028 A-0007
Dear Ms. Efimoff:
Woodward-Clyde International-Americas is pleased to provide the Carlsbad Municipal Water
District (CMWD) the attached report which presents our geotechnical engineering design
recommendations for the subject project. Our work has been performed in general
accordance with the CMWD's Agreement dated August 12, 1997.
The attached report presents discussions, conclusions, and recommendations pertaining to the
geotechnical aspects of the design of proposed sewer and storm drain pipelines and ancillary
features.
If the CMWD or their subconsultants have any questions, or if we can be of further service,
please feel free to give us a call.
Very truly yours,
WOODWARD-CLYDE INTERNATIONAL-AMERICAS
David L. Schug,
Associate
Woodward-Clyde Consultants • A subsidiary of Woodward-Clyde Group, Inc.
Sunroad Plaza 3, Suite 1000 • 1615 Murray Canyon Road • San Diego, California 92108
619-294-9400 • Fax 619-293-7920
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TABU OF CONTENTS
Section 1 Introduction 1-1
1.1 Sewer Replacement Project Description 1-1
1.2 Storm Drain Project Description 1-1
1.3 Purpose and Scope of Work 1-1
Section 2 Field Explorations 2-1
2.1 Site Reconnaissance, Work Plan, and Permits 2-1
2.2 Subsurface Explorations 2-1
2.2.1 Hollow-Stem Auger Borings 2-1
2.2.2 Cone Penetrometer Test Soundings 2-2
2.3 Groundwater Sampling 2-3
2.4 Groundwater Pump Tests 2-3
2.4.1 Well Installation 2-3
2.4.2 Well Development 2-3
2.4.3 Aquifier Testing 2-4
2.4.4 Aquifier Tests Data Evaluation 2-5
2.4.5 Aquifier Testing Results 2-7
2.4.6 Discussion of Aquifier Testing Results 2-7
Sections Laboratory Testing 3-1
3.1 Geotechnical Testing 3-1
3.2 Analytical Testing...;. 3-1
3.2.1 Groundwater Sample Analytical Results 3-1
3.2.2 Soil Sample Analytical Results 3-2
Section 4 Site, Soil, and Geologic Conditions 4-1
4.1 Surface Conditions 4-1
4.2 Geologic and Subsurface Conditions 4-1
4.2.1 Fill Soils '. 4-2
4.2.2 Terrace Deposits 4-2
4.2.3 Santiago Formation 4-4
4.3 Groundwater Conditions 4-4
4.3.1 Jefferson Street 4-5
4.3.2 Oak Avenue 4-5
4.3.3 Chestnut Avenue 4-5
4.3.4 NCTD Right-of-Way 4-6
4.4 Seismicity 4-6
4.4.1 Tectonic Setting 4-6
4.4.2 Faulting 4-6
4.4.3 Historical Seismicity 4-6
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TABIE OF CONTENTS
Section 5 Pipeline Design and Construction Considerations 5-1
5.1 General 5-1
5.2 Geologic Hazards 5-1
5.2.1 Fault Rupture 5-1
5.2.2 Ground Motion 5-1
5.2.3 Liquefaction 5-2
5.2.4 Landslides 5-3
5.3 Cut and Cover Construction 5-3
5.3.1 Excavation 5-3
5.3.2 Construction Slopes 5-4
5.3.3 Shoring 5-5
5.3.4 Dewatering 5-7
5.3.5 Trench Bedding and Backfill Materials 5-10
5.3.6 Backfill Compaction 5-10
5.3.7 Trench Cutoffs 5-11
5.3.8 Pipe Loads 5-11
5.3.9 Erosion, Sediment and Drainage Control 5-12
5.3.10 Pavement Restoration 5-12
5.4 Microtunnelling and Pipe Jacking 5-13
5.4.1 Anticipated Microtunnelling and Pipe Jacking Areas 5-13
5.4.2 Anticipated Ground Conditions and Behavior 5-13
5.4.3 Applicable Tunnel Excavation Methods 5-14
5.4.4 Frictional Resistance 5-16
5.4.5 Tunnel Muck Disposal 5-16
5.4.6 Settlement Estimates 5-16
5.4.7 Shaft Construction 5-17
5.4.8 Jacking Pipe Design Considerations 5-18
5.4.9 Instrumentation and Monitoring 5-18
5.5 Inlets and Access Holes 5-19
5.5.1 Foundation Preparation 5-19
5.5.2 Lateral Earth Pressures 5-20
5.5.3 Backfill Recommendations 5-20
5.5.4 Storm Drain Slope Anchors and Outlet Headwall 5-21
Section 6 Uncertainty and Limitations 6-1
Section? References 7-1
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List of Tables, Figures and Appendices
Tables
Table 1
Table 2
Table 3
Figures
Figure 1
Figure 2
Figure 3
Appendices
Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
Summary of Groundwater Analytical Testing
Summary of Construction Dewatering Estimates Carlsbad/Vista Sewer/Storm Drain
Categories of Ground Conditions For Soft Ground Tunnels
Vicinity Map and Alignment Map
Site Plan and Geologic Cross Section of Proposed Alignment
Regional Fault and Epicenter Map
Soil Boring Logs
CPT Soundings
Geotechnical Laboratory Test Results
Groundwater Dewatering Wells and Pump Test Results
Analytical Groundwater and Soil Test Results
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SECTION! )NE Introduction
This report presents the results of Woodward-Clyde International-Americas' (Woodward-Clyde)
geotechnical investigation for the subject project located in Carlsbad, California (Figure 1). This
report has been prepared exclusively for Carlsbad Municipal Water District (CMWD), the City
of Carlsbad (City), and their consultants for their use in evaluating the pipeline alignments and
for project design. In addition, this report may be used by the contractor to develop a general
understanding of the subsurface conditions that may affect construction but not a definitive
representation of site conditions in areas not explored during our field investigations.
For our study, we have discussed the project with Ms. Kelly Efimoff and Mr. Bill Plummer of
the CMWD, Mr. Doug Helming of Helming Engineering, Inc., representing the City of Carlsbad
engineering department. Mr. Terry Smith of Malcolm Pirnie, Inc., Mr. Steve Smith of Earth
Tech, Inc., and other members of the design team. We have also been provided with various
project drawings and conceptual plans for our use. Woodward-Clyde has reviewed information
including background data, geologic and topographic maps and reports, aerial photographs,
geotechnical reports for nearby project sites, and pertinent Woodward-Clyde project files.
1.1 SEWER REPLACEMENT PROJECT DESCRIPTION
The proposed sewer replacement pipeline will consist of approximately 2,700 lineal feet of
36-inch diameter pipeline along Jefferson Street, 3,500 lineal feet of 42-inch diameter pipeline
along Jefferson Street and Oak Avenue, 5,700 lineal feet of 48-inch diameter pipeline along the
North County Transit District (NCTD) right-of-way, and 1,750 lineal feet of 12-inch diameter
pipeline along Chestnut Avenue (Figure 1). A total of 24 sewer access holes are planned. Sewer
invert depths below grade will range from approximately 6 to 21 feet. We understand that there
are not any pump stations planned and the sewer will connect to existing laterals and sewers.
Specific components of the project may have changed since the issuance of this report.
1.2 STORM DRAIN PROJECT DESCRIPTION
The proposed storm drain pipeline will consist of approximately 5,500 lineal feet of pipeline
along the NCTD right-of-way, 700 lineal feet of pipeline along Oak Avenue and 1,750 lineal feet
of pipeline along Chestnut Avenue (Figure 1). The storm drain may be constructed in the same
trench as the sewer where the alignments are parallel. The storm drain pipe sizes are anticipated
to range from 30 to 102 inches in diameter. Storm drain invert depths below grade will range
from approximately 6 to 20 feet. The storm drain will ultimately flow into Agua Hedionda
Lagoon. Specific components of the project may have changed since the issuance of this report.
1.3 PURPOSE AND SCOPE OF WORK
The purpose of our geotechnical investigation is to provide geologic and geotechnical
information pertaining to the design and construction of both proposed sewer and storm drain
pipelines.
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SECTIONONE IntroductionnLJOur investigation addresses:
I • Surface and subsurface conditions
• Groundwater conditions
.r-, • Geologic hazards
} j • Construction dewatering
• Preliminary groundwater contamination screening
0 » Soil corrosivity
• Remedial earthwork measures
• Excavation characteristics
D « Temporary construction slopes
• Earthwork specifications
• Trench excavations and shoring
0 » Pipe loadings and settlements
• Pipe on slope stabilization measures
„ • Trenchless technology considerations
i • Pavements
— The discussions, conclusions and recommendations presented in this report are based on the
1 information provided to us, results of our field explorations and laboratory testing, review of
available information, geotechnical analyses, and professional judgment.
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SECTIONTWO Field Explorations
2.1 SITE RECONNAISSANCE, WORK PLAN, AND PERMITS
Prior to the initiation of field activities, Woodward-Clyde personnel conducted a site
reconnaissance of the proposed pipeline alignments to layout exploration locations and evaluate
access. Woodward-Clyde prepared a work plan prior to the start of field activities for the project.
The work plan described utility clearance measures, planned exploration locations, groundwater
sampling, and other planning information. Traffic control plans, street encroachment permits,
NCTD right-of-way access permission, and exploration permits were obtained prior to the start
of the field activities. Field meetings were held with representatives of the City, NCTD, and
local underground utility companies to discuss the areas to be investigated and to obtain
clearance for the subsurface explorations. An underground utility locating company was used to
survey the exploration locations for the presence of underground utilities prior to performing
field activities.
In addition, a general geologic and geotechnical reconnaissance of the pipeline alignments and
low elevation areas was performed from the southerly shores of Buena Vista Lagoon, around the
coastal shoreline, and to the northerly shores of Agua Hedionda Lagoon.
2.2 SUBSURFACE EXPLORATIONS
During the period from August 18 to August 26, 1997, Woodward-Clyde conducted a subsurface
investigation that included advancing 10 hollow-stem-auger soil borings, soil sampling, 23 cone
penetrometer test (CPT) soundings, and in-situ groundwater sampling. All field activities were
performed under the direction of a Woodward-Clyde engineer or geologist. Hollow-stem-auger
soil borings and CPT soundings were advanced at approximately 300- to 500-foot intervals along
H the proposed pipeline alignments at the approximate locations indicated on Figure 2.
To assess the presence of groundwater contamination along the proposed alignment, groundwater
samples were collected from 6 of the 23 CPT soundings in areas of existing or potential
groundwater contamination (e.g. service stations with documented hydrocarbon releases). Soil
samples collected from the upper 6.5 feet of selected soil borings were also submitted for
geochemical analysis to evaluate the presence of subsurface contaminants resulting from
historical activities in the vicinity of the alignment.
2.2.1 Hollow-Stem Auger Borings
Ten hollow-stem auger borings (Borings B-2, -8, -11, -14, -17, -22, -24, -27, -30 and -33) were
advanced at the approximate locations indicated on Figure 2. The borings are numbered
sequentially with the CPTs. The borings were advanced between August 21 and 26, 1997, by
Tri-County Drilling utilizing a CME-75HT drill rig equipped with 8!/2-inch diameter hollow-
jj stem augers to depths ranging from 29.5 to 40.5 feet. Soil samples were collected from each
- boring. Drive samples were generally collected at about 5-foot intervals using a modified
California sampler with stainless-steel liner tubes. When very dense soils were encountered and
collection of drive samples was not possible, soil samples were collected using a 5-foot-long NX
coring system. In addition, bulk soil samples of representative materials were collected from
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SECTIONTWO Held Explorations
selected soil borings. The soil borings were logged by a geologist in general accordance with
ASTM D 2488. Soil samples were also monitored in the field for the presence of organic vapors
using an organic vapor analyzer (OVA). All OVA readings were at a value of zero or one ppm.
A description of the soils encountered and specific sample intervals are presented on the boring
logs in Appendix A.
Relatively undisturbed soil samples retained for geochemical and geotechnical analysis were
sealed by placing polyethylene caps over each end of the stainless-steel tube. Soil samples
retained for geochemical analyses were placed in an insulated cooler with ice for transport to
Pacific Treatment Analytical Services, Inc. in San Diego, California, for analyses.
Woodward-Clyde chain-of-custody procedures were followed. Soil samples retained for
geotechnical laboratory analyses were transported to the Woodward-Clyde Geotechnical
Laboratory in San Diego. Soil samples will remain available for examination by the design
teams and bidding contractors.
Soil sampling equipment was decontaminated between uses by washing in an Alconox solution
and rinsing twice with distilled water. Soil cuttings from the soil borings were placed into
55-gallon drums and transported to the CMWD Calaveras Treatment Plant in Carlsbad for
temporary storage and disposal. Following the completion of drilling and sampling, the soil
borings were backfilled with bentonite grout and/or hydrated bentonite chips. Soil borings
advanced in the street were capped with asphalt to match the existing paving, and sealed with an
asphaltic sealing compound.
2.2.2 Cone Penetrometer Test Soundings
Twenty-three CPT soundings (C-l, -3, -4, -6, -7, -9, -10, -12, -13, -15, -16, -18, -19, -20, -21,
-23, -25, -26, -28, -29-31, -32 and -34) were advanced at the approximate locations indicated on
Figure 2. The CPT soundings were advanced between August 18 and 21, 1997 by Gregg In Situ,
Inc. utilizing a truck-mounted 20-ton capacity CPT rig. The CPT soundings were advanced to a
predetermined target depth or to refusal conditions, whichever occurred first. The CPT
soundings were advanced to depths ranging from 16 to 43 feet. Copies of the CPT soundings are
I provided in Appendix B.
The CPT soundings provide a continuous record of in-situ resistance utilizing an electric
piezocone. The piezocone measures soil bearing resistance at the cone tip, soil friction resistance
along the cylindrical friction sleeve, and pore water pressure. These parameters can be used with
empirical correlations to classify the soil types. However, the Soil Behavior Type (SBT)
j| indicated in the right-hand column on the CPT soundings (Appendix B) has classified soils with
*-* cementation as slightly more fine-grained than what is indicated in grain size distribution tests
performed on samples of soils from the borings. This condition may also be observed in
overconsolidated soils. In this respect, information presented on the boring logs take precedence
over the SBT descriptions on the CPT soundings.
Holes below the ground surface created by the CPT soundings were backfilled by grouting from
the bottom of the hole to the surface with a bentonite grout mix. CPT soundings advanced in the
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SECTIONTWO Field Explorations
street were capped with asphalt to match the existing paving, and sealed with an asphaltic sealing
compound.
2.3 GROUNDWATER SAMPLING
In-situ groundwater samples were collected at 6 CPT sounding secondary locations (C-3, -6, -10,
-16, -21 and -29) at depths approximately 2 to 3 feet below the estimated depth of groundwater.
Secondary locations are defined as immediately adjacent to the CPT location used for developing
the stratagraphic subsurface profile. Upon reaching the desired groundwater sampling depth, the
outer sleeve of the unit was retracted to expose a PVC screen within the steel rods. When
j | sufficient groundwater had accumulated within the PVC screen, a water sample was collected
using a teflon bailer (for filling sample containers for volatile organic compound analysis) or a
peristaltic pump (for filling sample containers for non-volatile organic compound analysis).
Water samples were placed into laboratory supplied containers, labeled, and placed in an
insulated cooler with ice for transport under chain-of-custody procedures.
2.4 GROUNDWATER PUMP TESTS
2.4.1 Well Installation
During the period from November 20 though November 24, 1997, eight groundwater monitoring
wells were installed in clusters of two (MW-11A/B, MW-18A/B, MW-22A/B, and MW-27A/B)
along the proposed alignment. Borings for the eight wells were drilled by West Hazmat Drilling
using 10-inch-diameter hollow-stem-augers. In order to prevent soil from entering the augers
during drilling, the lead auger was sealed with a wooden plug. Once the desired drilling depth
was achieved, the wooden plug was knocked out of the lead auger and the wells were installed
inside the augers.
The wells were constructed of 4-inch diameter Schedule 40 PVC, slotted (0.010-inch) over the
lower 20 feet in all eight wells, except well MW-27A which is slotted over the lower 25 feet.
The annulus surrounding the well casing was backfilled with No. 2/16 Lonestar sand to a depth
f | approximately 1.5- to 2-feet above the top of the slotted section. Approximately 2.5 to 6.5 feet
^ of medium-bentonite chips were placed above the sand filter pack. The bentonite was hydrated
with water after placement in the annulus of the borehole. The remainder of the borehole was
filled with concrete, into which a traffic-rated well covers were set. Well construction details are
provided on the boring logs and well construction diagrams included as Appendix D, and are
summarized in Table D-l.
2.4.2 Well Development
The eight wells were developed by West Hazmat Drilling by surging and bailing water from the
screened interval of each well. The screened section of each well was surged for about 20
minutes, and then bailed for approximately 30 to 45 minutes when the water was relatively free
of suspended sediment. Approximately 45 to 55 gallons of groundwater water was bailed from
each well during development.
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2.4.3 Aquifier Testing
2.4.3.1 Step-Drawdown Tests
Step drawdown tests were conducted in wells MW-11A, MW-18A, MW-22A and MW-27A on
November 25 and 26, 1997. A Jacuzzi Sandhandler™ electric submersible pump was utilized
for the tests and was set approximately one foot off the bottom of each well. The step-drawdown
tests were conducted to determine a sustainable discharge rate for the constant rate discharge
tests. Well MW-11A was pumped at rates of 0.7 and 1.0 gallons per minute (gpm), MW-18A
was pumped at rates of 1 and 2 gpm, MW-22A was pumped at rates of 3.1 and 5.5 gpm, and
MW-27 was pumped at rates of 1.1, 4.3, 7.0 and 10 gpm. Based on the results of the step
drawdown testing, a sustainable pumping rates of 0.70, 1.6, 5.1 and 7.1 gpm were selected for
wells MW-11 A, -18A, -22A and -27A, respectively.
Water levels were continuously monitored in the pumping well during pumping and recovery
using an In-Situ™ 4-channel data logger connected to a pressure transducer placed above the
pump inlet in each well. Manual measurements were also collected using an electronic water
level meter. Water discharge rates from the pumping well were monitored using a flowmeter,
bucket and a stopwatch. Water generated during each test was pumped into a temporary storage
tank located at each well cluster.
2.4.3.2 Constant Rate Discharge Tests
Constant rate discharge tests were conducted during the period from December 1 to December 8,
1997 at each of the four well clusters to determine hydrogeologic characteristics along the
proposed pipeline alignment. The results of the tests were utilized to obtain preliminary
estimates of transmissivity, storativity and hydraulic conductivity for future pipeline construction
purposes. Water generated during each test was pumped into a temporary storage tank located at
each well cluster. Specific details of the testing conducted at each well cluster is discussed
below.
2.4.3.2.1 Well Cluster MW-11A/B
A submersible pump was placed approximately 1 foot off of the bottom of the well and the
constant rate test was started at 1015 hours on December 1, 1997. Pumping continued for 375
minutes at an average rate of 0.70 gpm and concluded at 1630 hours when the pump was
stopped. Recovery was monitored for 60 minutes, from 1630 to 1730 hours. During pumping
and recovery, water levels were monitored in the pumping well (MW-11 A) and an observation
well (MW-1 IB) located 13.5 feet from the pumping well, using an In-Situ 4-channel data logger
connected to a pressure transducer placed in each well.
2.4.3.2.2 Well Cluster MW-18A/B
A submersible pump was placed approximately 1 foot off of the bottom of the well and the
constant rate test was started at 0947 hours on December 4, 1997. Pumping continued for 403
minutes at an average rate of 1.63 gpm and concluded at 1630 hours when the pump was
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SECTIONTWO Field Explorations
stopped. Recovery was monitored for 60 minutes, from 1630 to 1730 hours. During pumping
and recovery, water levels were monitored in the pumping well (MW-18A) and an observation
well (MW-18B) located 14 feet from the pumping well, using an In-Situ 4-channel data logger
connected to a pressure transducer placed in each well.
2.4.3.2.3 Well Cluster MW-22A/B
A submersible pump was placed approximately 1 foot off of the bottom of the well and the
constant rate test was started at 0945 hours on December 2, 1997. Pumping continued for 405
minutes at an average rate of 5.16 gpm and concluded at 1630 hours when the pump was
stopped. Recovery was monitored for 60 minutes, from 1630 to 1730 hours. During pumping
and recovery, water levels were monitored in the pumping well (MW-22A) and an observation
well (MW-22B) located 15.5 feet from the pumping well, using an In-Situ 4-channel data logger
connected to a pressure transducer placed in each well.
2.4.3.2.4 Well Cluster MW-27A/B
A submersible pump was placed approximately 1 foot off of the bottom of the well and the
constant rate test was started at 0905 hours on December 8, 1997. Pumping continued for 420
minutes at an average rate of 7.13 gpm and concluded at 1605 hours when the pump was
stopped. Recovery was monitored for 60 minutes, from 1605 to 1705 hours. During pumping
and recovery, water levels were monitored in the pumping well (MW-27A) and an observation
well (MW-27B) located 15 feet from the pumping well, using an In-Situ 4-channel data logger
connected to a pressure transducer placed in each well.
2.4.4 Aquifier Tests Data Evaluation
2.4.4.1 Constant Rate Discharge Tests
The constant rate discharge tests were analyzed using the AQTESOLV™ software package,
Theis solution for the analysis of pumping tests conducted in an unconfmed aquifer. The Theis
equations are as follows:
T = Q
4(7t)(s)
S =
,"'
K-b
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SECTIONTWO Field Explorations
where:
jj T = Transmissivity (ft2/day)
S = Storativity (unitless)
K = Hydraulic conductivity (ft/day)
b = saturated thickness of the aquifer (ft)
O r = distance from the observation well to the pumping well (ft)
s = drawdown in the observation well (ft)
t = time since pumping started (min)
Q = pumping rate in ft /min
TT = 3.14159...
W(u) = Dimensionless drawdown from the Theis type curve
1/u = Dimensionless time from the Theis type curve
A summary of the transmissivity, Storativity and hydraulic conductivity values calculated are
presented in Table D-2.
2.4.4.2 Recovery Tests
Theis's method of analysis of aquifer recovery test data (Kruseman and De Ridder, 1979) was
used to calculate aquifer transmissivities from the data collected during step-drawdown and
constant rate discharge aquifer testing during November and December 1997. Theis's method
involves plotting the residual drawdown (s') of the water level in a well, following cessation of
pumping, versus time since pumping started over time since pumping stopped (t/t') on a semi-log
scale. A straight line of best fit is then drawn through a section of the data deemed most likely to
relate to recovery of water level in the well associated with groundwater flow from the aquifer.
The equation used to calculate transmissivity (T) is as follows:
T = 2.30(Q)
4:i (6s)
where:
T = aquifer transmissivity (m2/d)
Q = groundwater discharge from the well (m3/d)
5s = the change in residual drawdown over one log cycle of t/t' of the line of best fit
through the recovery test data.
Recovery test data for wells MW-11 A, -18A, -22A and -27A included in Appendix D.
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The hydraulic conductivity of the aquifer surrounding the monitoring wells may be estimated by
dividing the calculated transmissivity by the thickness of saturated material penetrated by the well.
Based on the interpretations of recovery data, the calculated aquifer transmissivities and hydraulic
conductivities are shown on Table D-2.
2.4.5 Aquifier Testing Results
2.4.5.1 Constant Rate Discharge Test Results
Drawdown data collected from the four observation wells (MW-1 IB, -18B, -22B and -27B) were
utilized in calculating transmissivity, storativity and hydraulic conductivity. Evaluation of the
constant rate discharge test results using AQTESOLV™ indicated that transmissivities along the
proposed pipeline alignment range from 25.4 to 99 m /day, and storativity values range from 3.2
x 10~2 to 7.8 x 10"2. Hydraulic conductivities were calculated by dividing the transmissivity by
the saturated thickness of the aquifer. For the purposes of our calculations, the saturated interval
of the aquifer penetrated by the screened portion of the pumping wells was utilized as the
saturated thickness. The saturated thicknesses used in the hydraulic conductivity calculations
ranged from 16.8 feet (5.1 m) in well MW-22B to 23.4 feet (7.1 m) in well MW-27B. Calculated
hydraulic conductivities ranged from 1.14 x 10~2 to 6.95 x 10"3 cm/sec. It should be noted that
these calculated values are average values based on the thickness of the saturated sediments
penetrated by the wells. Due to the widely variable depositional sequences encountered along
the alignment, the heterogeneity of both the saturated terrace deposits and underling Santiago
Formation^ and the variation in the thickness and presence of the coarse materials encountered at
some locations, it is possible that thin layers or lenses of higher permeability soils are
contributing most of the water encountered during our investigation. Therefore, the pipeline
construction contractor should be prepared for the potential of significantly higher
transmissivities and hydraulic conductivities than those measured during this investigation.
2.4.5.2 Recovery Test Results
Evaluation of recovery test data from both the step-drawdown and constant rate discharge tests in
the pumping wells at each of the four well clusters indicated that transmissivity values ranged
from 0.22 m2/day in well MW-11A to 3.55 m2/day in well MW-27A, and hydraulic conductivity
values ranged from 4.94 x 10"5 cm/sec in well MW-11A to 5.89 x 10"4 cm/sec in well MW-27A.
In general, transmissivities and hydraulic conductivities measured during recovery testing were
one to two orders of magnitude lower than those measured during the constant rate discharge
tests.
2.4.6 Discussion of Aquifier Testing Results
There are limitations to the aquifer tests which must be considered. These include the following:
0 » Due to the geometry of the subsurface system (depth the pipeline invert, depths to
groundwater and thicknesses of geologic units) in which the aquifer tests were conducted, it
was not possible to avoid the effects of partially penetrating wells.
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• Project constraints did not allow for long-term pumping tests (24 to 72 hours) to be
conducted. Pumping duration ranged from seven to eight hours at each of the four selected
locations.
• It is assumed that the surrounding aquifer conditions where aquifer tests were conducted are
representative of conditions likely to be encountered during construction.
• The transmissivities, storitivities and hydraulic conductivities calculated from the test results
are average values within a possible range of values for soils in the saturated thickness of the
aquifer material penetrated.
The calculated transmissivities for each of the four monitoring clusters are in the range expected
for the materials in which they have been constructed. However, drawdowns observed in the
monitoring wells were typically inconsistent with drawdowns observed in the pumping wells,
which may be related to well construction. It is possible that fine sand and/or silt from the
formation has clogged or fouled the filter pack, thereby reducing hydraulic communication with
the surrounding formation. Additionally, the pumping duration, and casing and storage effects
observed in the data plots may lead to the overestimation of transmissivity and, subsequently,
hydraulic conductivity.
A comparison of the boring logs and the pumping test results suggest that the material at the
contact between the terrace deposits and the Santiago Formations and/or thin sand lenses within
the screened interval may be contributing a significant amount of water to the wells. Again, it
should be noted that these aquifer test results provide average transmissivity, hydraulic
conductivity and storativity values for the entire screened interval.
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SECTIONTHREE laboratorv Testing
3.1 GEOTECHNICAL TESTING
Samples of subsurface materials obtained during the field explorations were returned to
Woodward-Clyde's geotechmcal laboratory for further examination and testing. Soil testing
included moisture content, density, grain size distribution, compaction, direct shear and
unconfmed strength, permeability, and corrosion potential. Testing was performed in accordance
with applicable ASTM or other testing methods and procedures. Soil corrosivity potential testing
included pH, electrical resistivity, water soluble sulfate and water soluble chloride tests. The soil
corrosivity tests were performed by Clarkson Laboratory and Supply, Inc., of Chula Vista. The
results of laboratory testing indicate that subsurface materials are moderate to fairly corrosive to
metals. However, these materials may have a negligible attack rating for concrete.
The strength of the soils was evaluated by considering the density and moisture content of the
relatively undisturbed samples, the penetration resistance of the drive sampler, strength testing, and
other empirical correlations between soil characteristics, physical properties, and CPT soundings.
The results of geotechnical testing of soil samples are presented on the boring logs (Appendix A)
and in Appendix C.
3.2 ANALYTICAL TESTING
Soil and groundwater samples collected during this investigation were submitted for analyses to
Pacific Treatment Analytical Services, Inc., a state-certified laboratory located in San Diego,
California. Soil and groundwater samples were analyzed for volatile organic compounds
(VOCs) by EPA Method 8260, semi-volatile organic compounds (SVOCs) by EPA Method
8270, polychlorinated biphenyls (PCBs) by EPA Method 8080, and EPA Priority Pollutant
Metals by EPA Method 6010/7000. Soil samples were also analyzed for total petroleum
hydrocarbons (TPH), extended range, quantified as gasoline, diesel fuel and motor oil, by the
Department of Health Services (DHS) leaking underground fuel tank (LUFT) Method.
Groundwater samples were also analyzed for total recoverable petroleum hydrocarbons (TRPH)
by EPA Method 418.1.
3.2.1 Groundwater Sample Analytical Results
Groundwater sample analytical results are summarized in Table 1. Groundwater sample
analytical results indicate that TRPH, VOCs and PCBs were not detected in samples collected
from the six CPT sounding locations. With the exception of 9 micrograms per liter (ug/1) bis(2-
ethylhexyl)phthalate (trace concentration of a common lab contaminant) detected in the
groundwater sample collected from CPT sounding C-3, SVOCs were not detected.
Groundwater samples collected from CPT sounding locations C-6, -10, -16 and -29 contained
chromium at concentrations ranging from 0.3 to 0.7 milligrams per liter (mg/1). Copper was
detected at a concentration of 0.1 mg/1 in the groundwater sample collected from CPT sounding
C-29. Groundwater samples collected from CPT soundings C-6, -16 and -29 contained lead at
concentrations ranging from 0.1 to 0.2 mg/1. Groundwater samples collected from CPT
soundings C-6, -10 and -16 contained nickel at concentrations ranging from 0.1 to 0.2 mg/1.
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SECTIONTHREE laboratory Testing
Groundwater samples collected from CPT soundings C-6, -10, -16 and -29 contained zinc at
concentrations ranging from 0.3 to 0.8 mg/1. Mercury was detected in groundwater samples
collected from CPT soundings C-3, -6, -10, -16 and -29 at concentrations ranging from 0.0001 to
0.0009 mg/1. Selenium was detected in groundwater samples collected from CPT soundings C-3
and -16 at concentrations of 0.004 and 0.04 mg/1, respectively. No other metals were detected at
the detection limits specified on the laboratory data sheets included in Appendix D.
3.2.2 Soil Sample Analytical Results
Laboratory analytical results indicated that VOCs, SVOCs, PCBs and TPH were not detected in
j soil samples collected from Borings B-l 1, -14, -17 and -24. Soil samples collected from Borings
^ B-2, -8, -22, -27, -30 and -33 were only analyzed for TPH and did not contain detectable
concentrations.
Soil samples collected from Borings B-ll, -14, -17 and -24 contained chromium at
concentrations ranging from 14 to 16 mg/kg. In addition, the soil sample collected from boring
B-24 contained 12 mg/kg zinc. No other metals were detected at the detection limits specified on
the laboratory data sheets included in Appendix D.
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SECTIONFOUR Site, Soil and Geologic Conditions
Our knowledge of the site conditions has been developed from a review of available information,
area geology, pervious investigations in the vicinity, and the field and laboratory programs
undertaken for this investigation.
4.1 SURFACE CONDITIONS
The coastal area of Carlsbad between Buena Vista Lagoon and Agua Hedionda Lagoon is
characterized by narrow sand and cobble beaches backed by seacliffs and moderate to steeply
sloping coastal bluffs. A narrow linear ridge parallels the coastline immediately east of the bluff
top with elevations ranging from +50 to +60 feet MSL. The east facing slopes of this ridge
extend down to the NCTD right-of-way. Elevations along the NCTD right-of-way in Carlsbad
area range from about +30 to +45 feet MSL. East of the NCTD right-of-way, the topography
rises in a series of stepped terraces for several miles.
Surface elevations along Jefferson Street in the project area range from +55 to + 69 feet MSL
from south to north, respectively. Along Oak Avenue the elevations range from +40 to +55 from
west to east, respectively. Along Chestnut Avenue elevations range from +43 to +60 from west
to east, respectively. Along the NCTD right-of-way the elevations range from +5 to +44; the low
point is located adjacent to Agua Hedionda Lagoon and 2 high points are located near Tamarack
Avenue and at the terminus of Acacia Avenue. The project segments along Jefferson Street, Oak
Avenue, and Chestnut Avenue are adjacent to residential and commercial properties and have
significant street improvements, sidewalks, driveway entrances, above and below ground
utilities, trees, and other surface features.
The project segment along the NCTD right-of-way is basically undeveloped with the exception
of NCTD railroad tracks and utilities. The majority of the ground surface is covered with sparse
vegetation and localized debris. However, a narrow unlined drainage ditch is present along the
east side of the right-of-way between Juniper Avenue and Oak Avenue in the project area. The
east side of the southern end of the NCTD right-of-way steeply descends toward Agua Hedionda
Lagoon. A concrete-lined V-shaped drainage ditch about 200 feet long with about 30 feet of
elevation change currently exists in this area. Vegetation along the shoreline of Agua Hedionda
Lagoon is relatively heavy.
4.2 GEOLOGIC AND SUBSURFACE CONDITIONS
The geology of the Carlsbad area is dominated by Quaternary-age terrace deposits that have been
deposited on wavecut platforms cut into Tertiary-age sedimentary deposits of the Santiago
Formation. These terraces were formed as step-like benches cut by ancient seas and
subsequently elevated above sea level. Once elevated above sea level, the wave-cut bench
(abrasion platform) and overlying thin marine deposits collect non-marine sedimentary cover
consisting primarily of sandy deposits. There are a series of progressively older and higher
terrace surfaces benched into the Tertiary sedimentary deposits in the Carlsbad area. The
lithology of the underlying Tertiary sedimentary deposits include sandstones (predominantely
cemented sand) and siltstones (predominantely cemented silt) of the Santiago Formation.
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SECTIONFOUR Site, Soil and Geologic Conditions
For the purpose of site characterization, the subsurface materials encountered at the exploratory
locations are categorized (in the order of increasing age) into three geologic units consisting of
man-placed fill soils, Pleistocene-age terrace deposits, and Tertiary-age Santiago Formation.
Each geologic unit can be distinguished by its origin or depositional character and has somewhat
("I different compositional characteristics. These geologic units are described in the following
^ paragraphs with generalized discussions pertaining to the site geology. A generalized geologic and
groundwater profile is shown on Figure 2.
4.2.1 Fill Soils
Fill soil encountered during the investigation generally consisted of dry to moist, loose to
medium dense sandy soils with trace amounts of gravel. Fill soils were encountered in
explorations C-l, B-2, B-l 1, C-32, B-33 and C-34 at depths ranging from 1 to 14 feet. Although
significant thicknesses of fill soil were not encountered in most explorations along the proposed
alignment, shallow fill soils are expected to be present at other locations along the proposed
alignment. Additionally, existing roadways, the NCTD right-of-way, and backfilled underground
utility easements having variably thick fill soils will likely intersect or run parallel with the
proposed pipeline alignments. The depth and consistency of the fill soils may be expected to
vary significantly depending on the amount of development or other man-made disturbance that
has occurred at a particular location.
The results of this investigation and observations of existing surface conditions suggest that fill
soils are likely to consist of a wide variety of sandy to fine-grained material. Fill soils may have
varying amounts of gravel and cobbles. Fill soils may range from loose to dense depending
Q original method of placement in either City streets or the NCTD right-of-way. CPT tip
resistance values range from 10 to 150 tsf for fill soils. Trenches excavated vertically in these fill
soils may be considered unstable below depths of 2 to 3 feet.
4.2.2 Terrace Deposits
Nonmarine Pleistocene-age terrace deposits are found locally throughout the proposed pipeline
alignments. The moist to wet, medium dense to very dense terrace deposits encountered during
our field explorations are characterized as yellowish to reddish brown to light gray and olive,
weakly to moderately cemented, silty to poorly graded medium to very fine sands. Terrace
deposits are anticipated to depths ranging from 15 to 30 feet along the entire proposed alignment
with the exception of the area adjacent to Agua Hedionda Lagoon where the thickness reduces to
less than 10 feet (Figure 2).
In general, tested upper portions of the terrace deposits (0 to 10-foot depths) have fine-grained
contents (percent passing the No. 200 sieve) on the order of 15 to 25 percent. Although not
encountered in our borings, these upper terrace deposits may also have localized areas of clayey
sand. The tested lower portions of the terrace deposits (depths greater than 10 feet) have fine-
grained contents ranging from 1 to 11 percent with the exception of sample B-l4-3 (at a depth of
11 feet) which have a 17 percent fine-grained content. The terrace deposits are not considered
cohesive or very expansive based on their low fine-grained content.
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SECTIONFOUR Site, Soil and Geologic Conditions
Terrace deposits may also have gravels in localized areas as revealed in Borings B-2, B-8, and
B-22. Terrace deposit gravels were not observed in any other borings. However, observations
during the field reconnaissance around the local lagoons and shoreline areas indicated that
exposed lower contacts of the terrace deposits may have some basal gravels. Cobbles were not
encountered in our borings. Nevertheless, cobbles were observed in the exposed contact between
the terrace deposits and Santiago Formation in the near vertical cut slope along the west side of
the NCTD right-of-way near Agua Hedionda Lagoon. However, for the most part, significant
gravels and cobbles are not likely to be present along the geologic contact but should be
anticipated in localized areas.
Blow counts in the terrace deposits typically ranged from 15 to 52 blows per foot and generally
increased with depth. However, observed terrace deposits in Boring B-33 near Agua Hedionda
Lagoon had equivalent blow counts on the order of 11 to 17 blows per inch (134 to 200 blows
j| per foot). From a blow count perspective, the terrace deposits may be considered medium dense
^ to very dense.
As noted in Section 2.2.2 of this report, the CPT soundings may typically classify
overconsolidated sandy soils with cementation as slightly more fine-grained than what is
indicated in grain size analyses of the soil samples. As a result, the indicated SBTs presented on
the CPTs at depths corresponding to the terrace deposits also include silts and sandy silts.
However, high silt content materials were not directly observed in the borings. In this respect,
CPT tip resistance results may be considered indicative of the dry strength of the terrace deposits
only. CPT tip resistance in the terrace deposits generally ranged from 50 to 500 tsf. The majority
of CPT tip resistance values were in excess of 100 tsf.
Moisture content and dry densities of the upper terrace deposits ranged from 4 to 17 percent and
99 to 112 pcf, respectively. Moisture content and dry densities of the lower terrace deposits
ranged from 5 to 26 percent and 94 to 107 pcf, respectively. The results of 3 laboratory
compaction tests indicated maximum dry densities of 127.5 to 135 pcf and optimum moisture
contents of 9.5 to 7.5 percent, respectively. Based on these results, it appears that terrace
deposits may be considered to be at less than 90 percent relative compaction and could be subject
to fast raveling upon wetting and 10 to 15 percent volume shrinkage if recompacted.
The terrace deposits contain higher percentages of clay and iron weathering products that
enhance the apparent dry strength of the material. Saturated direct shear strength tests indicated
peak internal friction angles of 39 to 42 degrees and saturated cohesion intercepts of 0 to 200 psf
In our opinion, a friction angle of 38 degrees and no cohesion may be used to characterize the
terrace deposits for long-term engineering design purposes. However, these materials do exhibit
variable dry strength from weak to moderate cementation which may be lost upon wetting.
Based on empirical correlations between grain size distribution and density, it is anticipated that the
upper terrace deposits may have permeability values on the order of 10"4 to 10"6 cm/sec. Lower
terrace deposits may have permeability values on the order of 10"3 to 10"5 cm/sec. More and less
permeable materials may exist in the terrace deposits in localized zones.
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SECTIONFOU R Site, Soil and Geologic Conditions
The results of pH and resistivity testing of terrace deposits indicate that these soils are moderate to
fairly corrosive to metals. However, based on water soluble chloride and sulfate testing, these soils
may have a negligible degree of attack on concrete structures.
In our opinion, the upper and lower portions of the terrace deposits may be considered as medium
and high quality feeder-beach nourishment fill material. Due to the predominant oxidized
brownish colors of the terrace deposits, these soils may be less suitable for conventional beach
fill construction and therefore could be placed directly into the surf zone if desired.
4.2.3 Santiago Formation
The Tertiary-age Santiago Formation was encountered to the maximum depth explored beneath
the terrace deposits along the entire length of the proposed alignment. The Santiago Formation
encountered during our investigation generally consisted of interbedded, moist to wet, dense to
very dense, weakly to moderately-cemented sandstone and hard siltstone. The observed Santiago
Formation was predominately light gray and light brown in color with subtle shades of yellow
and olive. Tested samples from the Santiago Formation have fine-grained contents on the order
of 8 to 72 percent; typically, the formation has fine-grained contents of 15 to 50 percent which)
may be correlated silty to clayey sands. Our borings did not indicate the presence of gravel or
cobbles in the Santiago Formation. Moisture contents and dry densities of the Santiago
Formation ranged from 11 to 20 percent and 109 to 125 pcf, respectively, with the exception of
0 sample B-30-9 (at a depth of 36 feet) which had a moisture content of 30 percent and dry density
of 91 pcf.
In general, blow counts in the Santiago Formation were in excess of 100 blows per foot.
However, the observed Santiago Formation in Boring B-2 had blow counts ranging from 71 to
87 blows per foot. Blow counts of 39 and 29 blows per foot were registered in Borings B-8 and
B-30, respectively. From a blow count perspective, the Santiago Formation may be considered _
very dense. CPT soundings indicate stiff fine-grained materials and moderately to highly
U cemented sands in the Santiago Formation. Unconfined compressive strengths for 8 selected test >.
samples ranged from 49 to 21,321 psf. Only 2 of the tested samples had unconfmed compressive
strengths less than 5,000 psf. High strength concretions were not encountered on our borings,
but may exist throughout the pipeline alignments in the Santiago Formation.
Based on empirical correlations between grain size distribution and density, it is anticipated that
the silty sands of the Santiago Formation have permeability values on the order of 10"5 to
1 f\ fi10" cm/sec. Clayey sands have permeability values on the order of 10 to 10" cm/sec. More and
less permeable materials may exist in localized zones.
4.3 GROUNDWATER CONDITIONS
Groundwater was encountered at the time of drilling at depths ranging from 9 to 34 feet below
ground surface in 9 of the 10 soil borings advanced along the proposed alignment. In general,
groundwater was typically encountered within 10 to 15 feet of the ground surface and was
encountered at greater depths approaching the northern (toward Buena Vista Lagoon) and
southern (toward Agua Hedionda Lagoon) ends of the alignment. Groundwater conditions in the
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SECTIONFOUR Site, Soil, and Geologic Conditions
coastal strip are characterized by frequent perched water zones just above and below the terrace
contact with the Santiago Formation. Groundwater levels are thought to fluctuate significantly
with seasonal rains, local irrigation practices, and site specific conditions. Based on our
experience and on our review of previous borings and monitoring wells above the bluffs, we
estimate groundwater levels typically to be within 5 to 10 feet above the terrace contact with the
Santiago Formation.
Groundwater conditions for specific segments of the alignment are summarized in the following
paragraphs (also refer to Figure 2). We recommend that groundwater levels 5 feet higher than
those shown in Figure 2 be used for design.
4.3.1 Jefferson Street
Estimated groundwater depths along the Jefferson Street segment range from approximately 11.5
to 17.5 feet. Based on the surficial topography, groundwater is anticipated to flow to the
northwest toward Buena Vista Lagoon between Station '90+00 (intersection of Laguna Drive and
Jefferson Street) and 116+30 (northern end of the proposed alignment), and to the
west-southwest toward the Pacific Ocean between Station 69+55 (intersection of Jefferson and
Street and Oak Avenue) and Station 90+00. Estimated groundwater elevations over this segment
of the alignment range from approximately +55 feet MSL at the northern end of the alignment to
approximately +35 feet MSL near the intersection of Jefferson Street and Grand Avenue.
4.3.2 Oak Avenue
Estimated groundwater depths along the Oak Avenue segment range from approximately 10.5 to
15.5 feet. Based on the surficial topography, groundwater flow is anticipated to the
west-southwest toward the Pacific Ocean between Station 69+55 (intersection of Jefferson Street
and Oak Avenue) and Station 56+00 (intersection of Oak Avenue and the NCTD right-of-way).
Estimated groundwater elevations over this segment of the alignment range from approximately
+40 feet MSL at the intersection of Jefferson Street and Oak Avenue to approximately +30 feet
MSL at the intersection of Oak Avenue and the NCTD right-of-way.
4.3.3 Chestnut Avenue
Estimated groundwater depths along the Chestnut Avenue segment range from approximately 5
to 13.5 feet. Based on the surficial topography, groundwater is anticipated to flow to the west
toward the Pacific Ocean between Station 18+00 (intersection of Chestnut Avenue and Harding
Street) and Station 0+00 (intersection of Chestnut Avenue and the NCTD right-of-way).
Estimated groundwater elevations over this segment of the alignment range from approximately
+46 feet MSL near the intersection of Chestnut Avenue and Harding Street to +33 feet MSL at
the intersection of Chestnut Avenue and the NCTD right-of-way.
Alignment stationing referenced in this report and Figure 2 are based on preliminary stationing presented on the
plans entitled "Vista/Carlsbad Interceptor Phase III," prepared by Wilson Engineering, dated January 25, 1991.
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SECTIONFOU R Site, Soil, and Geologic Conditions
4.3.4 NCTD Right-of-Way
Estimated groundwater depths along the NCTD right-of-way segment range from approximately
9 to 30 feet. Based on the surficial topography, groundwater is anticipated to flow to the
west-southwest toward the Pacific Ocean between Station 56+00 (intersection of Oak Avenue
and the NCTD right-of-way Drive and Jefferson Street) and 15+75 (intersection of the NCTD
right-of-way and Tamarack Avenue), and to the southwest-south toward Agua Hedionda Lagoon
between Station 15+75 and Station 0+00 (southern end of the proposed alignment). Estimated
groundwater elevations over this segment of the alignment range from +33 feet MSL at the
intersection of Chestnut Avenue and the NCTD right-of-way to approximately +5 feet MSL at
the southern end of the alignment. Tidal fluctuations will influence groundwater elevations at
the proposed storm drain outlet headwall location.
4.4 SEISMICITY
4.4.1 Tectonic Setting
The tectonic setting of the San Diego County area is influenced by crustal plate boundary
interaction between the Pacific and North American lithospheric plates. This crustal interaction
occurs along a broad zone of northwest-trending, predominantly right-slip faults that span the
width of the Peninsular Ranges and extend offshore into the California Continental Borderland
Province west of California and northern Baja California. At the latitude of Carlsbad, this zone
extends from the San Clemente fault zone, located approximately 60 miles southwest of Carlsbad
to the San Andreas fault, located about 70 miles northeast of Carlsbad.
4.4.2 Faulting
The nearest active fault to the project area is the Rose Canyon-Offshore Zone of Deformation
(OZD)-Newport Inglewood fault zone which has been located offshore approximately 3 to
4 miles based on marine geophysical surveys. The active Coronado Bank and San Diego Trough
faults are located further offshore at distances of approximately 20 miles and 30 miles,
respectively. Approximately 25 miles to the northeast is the active Elsinore fault zone. Other
more distant active faults capable of generating strong ground motions in the Carlsbad area
include the San Jacinto and San Andreas faults to the east, the San Miguel-Vallecitos and the
Agua Blanca faults to the south. Figure 3 presents the major regional faults of tectonic
significance and earthquake epicentral locations for southern California.
4.4.3 Historical Seismicity
Historical seismicity of the Carlsbad area has been relatively low compared to other areas of
southern California and northwestern Baja California, Mexico (Figure 3). Only a limited number
of small earthquake events have been reported in the area during the period of instrumental
record (since the early 1900s). Local earthquake epicenters that have been interpreted to be
associated with the Rose Canyon-OZD fault zone include a series of small-to-moderate
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SECTIONFOUR Site, Soil, and Geologic Conditions
earthquakes in July of 1985. The largest event reported at that time was a Magnitude 4.2 and
was generally centered within San Diego Bay. A similar series of earthquakes in coastal San
Diego County occurred in 1964.
In contrast, the surrounding region of southern California and northwestern Baja California,
Mexico have had a higher rate and intensity of seismic activity. Many moderate-to-large
earthquakes have occurred within the region during the last 50 to 100 years. Specifically, the
San Jacinto and San Miguel faults have been the sources of significant historic earthquakes.
Other major active faults that have produced recurring earthquakes having a magnitude greater
than 4.0 are the Elsinore fault zone and the Coronado Bank fault zone, which are mapped
approximately 25 miles northeast and 20 miles southwest (offshore), respectively.
An earthquake with an estimated Magnitude 6.5 occurred several miles offshore of Carlsbad and
Encinitas in 1800. However, the magnitude, location and source are uncertain.
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SECTIOHFIVE Pipeline Design and Construction Considerations
5.1 GENERAL
The following section provides discussions and recommendations regarding the design and
construction of the pipelines.
We understand that conventional cut and cover construction (trench construction) may be used
for much of the planned pipeline alignments. However, due to the presence of existing buried
utilities, street and property improvements, vehicular and railroad traffic, noise, potential safety
hazards, shallow groundwater conditions, potential subsurface contamination, public perceptions,
social impacts, and other factors, pipeline construction using trenchless technology may be
considered wherever the conditions appear favorable. We anticipate that trenchless construction
will be utilized at crossings beneath Carlsbad Village Drive, Tamarack Avenue, and the railroad.
Trenchless technology for pipeline installation includes microtunnelling, pipejacking, and
conventional tunnelling. Each method of trenchless construction has its own advantages and
disadvantages. Trenchless methods can significantly reduce or eliminate the need for
groundwater dewatering, soil stockpiling, shoring, trench backfill, pavement resurfacing, and
dust control. Surface settlements and the effects of bad weather are also reduced. Use of
trenchless technology also reduces the safety risk to the public by not having open trenches and
by not having heavy equipment interfere with traffic flow. Pipeline installations greater than 3
feet in diameter or more than 10 feet deep using trenchless construction methods are often very
competitive with conventional cut and cover construction. Installation of pipelines using
trenchless methods typically can meet requirements for line and grade to within relatively tight
tolerances. In any case, protection and restoration of existing improvements should be the
responsibility of the contractor, in accordance with Section 7.9 of the Standard Specifications for
Public Works Construction (Green Book).
We recommend that a contractor experienced in trenchless technology construction be retained
by the CMWD and the City during the final design process in order to evaluate the plans,
specifications, and constructibility prior to the project going out to bid.
5.2 GEOLOGIC HAZARDS
5.2.1 Fault Rupture
Many northeasMrending faults are mapped along the north county coastal bluffs as described in
Treiman (1993). Some of the more pronounced faults may extend inland some distance and
potentially intersect the alignment. Our work has not included a site specific assessment of
faulting inasmuch as none of these faults are reported to be "active."
5.2.2 Ground Motion
The project area will likely be subject to moderate to severe ground shaking in response to a
local or more distant large magnitude earthquake occurring during the life of the planned
pipelines. Peak ground acceleration for pipeline design (if used) may be estimated from a
deterministic assessment of probable ground motion generated from an earthquake occurring in
the OZD. The maximum credible earthquake from the OZD has been estimated to be on the order
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SECTIONFI YE Pipeline Design and Construction Considerations
of Magnitude 7. This level of earthquake may generate a peak ground acceleration on the order
of 0.5 to 0.6 g or greater. Similarly, the estimated maximum probable earthquake corresponding
to a 10 percent chance of recurrence in 50 years has been estimated to generate a peak ground
acceleration on the order of 0.3 to 0.4 g (Berger and Schug, 1991). The pipeline engineer should
evaluate what seismic design procedures which are the most appropriate for the project.
5.2.3 Liquefaction
Seismically induced soil liquefaction is a phenomenon in which loose to medium dense,
saturated granular materials undergo matrix rearrangement, develop high pore water pressure,
and lose shear strength due to cyclic ground vibrations induced by earthquakes or other means.
This rearrangement and strength loss may be followed by a reduction in bulk volume.
n Manifestations of soil liquefaction can include loss of bearing capacity below foundations,
surface settlements of level ground, and instability in areas of sloping ground. Soil liquefaction
can also result in increased lateral and uplift pressures on buried structures. Light-weight or
unrestrained buried structures may float upward to the ground surface if not properly restrained.
Based on anticipated pipeline depths, groundwater elevations, and soil types and strength, ground
motions, and other factors, we have made an evaluation of the soil liquefaction potential along
the proposed pipeline alignments. The evaluation is based on empirical correlations with
observations of liquefaction and non-liquefaction that have resulted from previous earthquakes.
In our opinion, soils along the proposed pipeline alignments do not represent, a significant
liquefaction hazard.
In our opinion, only one area within the project limits may be considered to have a liquefaction
susceptibility potential. This area is at the southerly terminus of the proposed storm drain at
Agua Hedionda Lagoon. Although no explorations were performed in this area due to physical
access restrictions, it is our opinion that lagoon shoreline areas where the ground surface is below
an elevation of about +5 feet MSL may be subject to soil liquefaction given the design ground
motions.
Soil liquefaction, if it were to occur, would likely manifest itself in localized ground subsidence
and possible lateral spreading. We estimate that total surface settlements on the order of 1 to 2
inches may occur at the storm drain outfall end if the potentially liquefiable subsurface
conditions are not mitigated. Displacements due to lateral spreading could be significantly
greater but cannot be determined. These potential settlements may be reduced to a negligible
amount if the subsurface conditions are improved.
We recommend that the alluvial areas below the planned storm drain outfall be remediated with
respect to soil liquefaction potential. Mitigation for these conditions should consist of
overexcavation and recompaction of loose near surface sediments in this area. Conventional over
excavation and recompaction consists of removing existing loose sediments and then placing
these materials back as compacted fill or with %" gravel. The estimated depth of loose sediment
removal is to an elevation of +0 feet MSL and 5 feet laterally away from the structure in all
directions. The actual depth of soil removal should be determined in the field at the time of
construction.
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SECTIONFIVE Pipeline Design and Construction Considerations
5.2.4 Landslides
Only one landslide has been identified near the proposed pipeline alignments. This landslide is
located approximately 3,200 feet south of the sewer access hole at Station 0+00 along the east side
of the access road embankment adjacent to the NCTD right-of-way. This landslide is
approximately 50 feet long by 20 feet high. This landslide is not within the proposed pipeline
alignments. The NCTD should be notified of this landslide condition prior to the start of
construction by either the City or CMWD. Repairs could be performed during construction of the
adjacent storm drain pipeline and outlet headwall. Recommendations for landslide repair are
beyond the scope of this report. Woodward-Clyde can prepare a mitigation design, plans, and
specifications for the landslide repair upon request.
5.3 CUT AND COVER CONSTRUCTION
5.3.1 Excavation
Anticipated soil and excavation characteristics of materials along the proposed pipeline
alignments are based on results from soil borings, CPT soundings, laboratory test data, and
knowledge of the local soil conditions. These characteristics may vary somewhat within a given
geologic unit. The majority of the excavations will be within the medium dense to very dense
terrace deposits. Fill material was observed in some of the borings but were generally less than
several feet in thickness except at the extreme northern and southern end of the project area.
Excavated terrace deposit materials are likely to consist of silty to poorly graded sand with
possibly some gravel and few cobbles. Materials excavated from the Santiago Formation are
likely to be silty to clayey sands derived from the weakly to moderately cemented sandstone and
jj siltstone. Localized zones of strong cementation and possible concretions can result in material
^ which is more difficult to excavate.
Occasional gravel and cobbles may be present in localized areas along the pipeline alignments,
most likely just above the contact of the Santiago Formation. The handling of these materials
typically depends upon the location and depth of excavation, in-situ subsurface conditions, and
the type of excavation equipment chosen. The determination of the most appropriate method of
handling such materials should be the sole responsibility of the contractor.
Heavy duty excavators should be capable of excavating the fill, terrace deposits, and Santiago
Formation soils along the alignment. Rock breakers or hoe rams may be required to excavate
some localized zones. Anticipated ground conditions within the project area suggest that the
excavations may stand without immediate support. Above the groundwater, these materials may
stand for short to long periods of time. Excavations made in terrace deposits for the railroad
adjacent to Buena Vista Lagoon and Agua Hedionda Lagoon indicate that nearly vertical slopes
are possible. Excavations made below the groundwater (at or near the terrace deposits/Santiago
Formation contact) may not stand without immediate support and there may be flowing sands
into the excavation.
To minimize external loads on a pipe installed in a trench or to provide uniform support, the
width of trenches should be selected so that the minimum required clear space (at least 6 inches)
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SECTIOHFIVE Pipeline Design and Construction Considerations
is provided for on each side of the pipe. Greater lateral width may be required for access of
manual compaction equipment.
Since no changes to the existing ground surface along the pipeline alignments are planned, the
net stress change in the underlying soils is considered negligible. Provided that temporary
dewatering and excavation are properly performed during construction, the majority of the native
soils at the presently planned invert level along the pipeline alignments are expected capable of
providing a stable trench bottom. However, loose materials of variable thickness may exist at the
end of the storm drain outfall near Agua Hedionda Lagoon. Loose, soft, or disturbed soils
exposed at the trench bottom should be removed and replaced with pipe bedding materials. The
extent of these materials should be further evaluated, when and if exposed during construction.
The top of excavations shall be graded to prevent runoff from entering the excavation, wetting
the soils, and eroding the excavated faces. Surcharge loads from vehicle parking and traffic or
stockpile materials should be set back from the top of temporary excavation a horizontal distance
equal to at least the depth of excavation. Even with the implementation of these
recommendations, sloughing of the surface of temporary excavations may still occur, and
workers should be adequately protected.
5.3.2 Construction Slopes
We recommend that unbraced temporary construction slopes along the NCTD right-of way be
cut back at the following full height inclinations:
Location
South of Station 6+00
(Mostly Fill Soils)
North of Station 6+00
(Mostly Terrace Deposits)
Excavation Depth
(feet)
Oto5
5 to 10
10 to 15
15 to 20
20 to 25
Oto5
5 to 10
10 to 15
15 to 20
20 to 25
Slope Inclination
(horizontahvertical)
1/2:1
3/4:1
1:1
1-1/2 : 1
2:1
Vertical
1/2:1
3/4:1
1:1
1-1/2 : 1
In all cases, we recommend that top of slope for the trench excavation be located at least 20 feet
away from the east rail of the railroad tracks. Temporary construction slopes, as described above,
are considered to have a factor of safety against failure in excess of 1.2 for dewatered static
conditions. These slopes have not been analyzed for seismic conditions since they are only
considered temporary.
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SECTIONFI YE Pipeline Design and Construction Considerations
We recommend that measures be taken during construction of the storm drain outlet headwall
adjacent to Agua Hedionda Lagoon to minimize any overexcavation of the embankment fill to
the west (within the NCTD Right-of-Way). Construction in this area should be as far away from
the existing slope toe as possible. These recommendations are made with respect to avoid
producing a pop-out landslide condition in this area as described in Section 5.2.4 of this report.
The slope inclinations presented above are for planning and building purposes only. The
contractor should perform his own evaluation of temporary construction slope conditions which
will provide safe working conditions. All temporary construction slopes, including trenches for
buried pipes and other utilities, should comply with local and Cal-OSHA safety guidelines. The
top of all excavations shall be graded to prevent runoff from entering the excavation. It should
be recognized that the safety of all temporary construction slopes are the responsibility of the
contractor.
5.3.3 Shoring
We anticipate that nearly all excavations will require shoring. Limited construction space and the
need to avoid excessive community disruption dictate that a shored excavation would probably
be required throughout the cut-and-cover alignments. Due to the presence of numerous existing
buried pipes and underground conduits within the project area, interference with existing utilities
may be encountered during shoring installation. Train loadings should be included in the lateral
shoring pressures for areas within the NCTD right-of-way. While it may be possible to leave
portions of the trench unshored for short time periods, the trenches will require shoring if
personnel are to enter or work near them.
Anticipated shoring systems include the following:
• Trench boxes
• Soldier piles with steel plate or wood lagging
• Trench bracing (speed shoring)
It should be considered that the ground may exhibit different behavior above and below the
groundwater. In some conditions, trenches may be constructed without shoring and without
personnel entering or standing near the trench. This approach may be considered for very
shallow excavations but is generally unsuitable for most of the proposed project situations.
Trenches shallower than about 10 feet may be left unshored, at the contractor's accepted risk,
provided that Cal-OSHA safety regulations are followed. However, unshored trenches may
experience local instability due to adjacent fill soils within previously backfilled trenches. Lack
of shoring support may also affect the adjacent buried utilities themselves. In this respect,
existing adjacent buried utilities can be weakened or compromised by the slightest movements
which can initiate cracking or other forms of distress which could accelerate long-term
deterioration.
Box shoring or trench shields may be suitable for some of the ground conditions anticipated
within the project area, but these systems still require the ground to "stand up" prior to installing
the shoring. Localized clean sand, loose zones or zones with groundwater seepage may not have
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SECTIOHFIVE Pipeline Design and Construction Considerations
sufficient stand up time. This would require that the trench shield be dropped as the excavations
proceeds or that a shoring system such as soldier piles and lagging be installed as the excavation
is made.
We recommend that cantilever shoring systems which have suitable dewatered conditions be
designed using a active equivalent fluid weight of 35 pcf. We recommend that braced shoring
systems which have suitable dewatered conditions be designed using a uniform lateral earth
pressure of 20H psf where H is measured in feet. A passive equivalent fluid weight of 350 pcf
and 150 pcf may be used for conditions above and below the groundwater table, respectively. A
lateral loading of 400 psf for the first 10 feet below the level ground surface may be used to
simulate heavy traffic (HS-20 truck loading). All other surcharge loadings on the shoring system
may be taken as an additional uniform lateral earth pressure of 0.4q where q if the vertical
surcharge pressure. The upper 2 feet within the passive resistance zone should be neglected in
the shoring system design calculations.
We recommend that trenches and excavations be designed and constructed in accordance with
OSHA regulations. These regulations provide general trench sloping and shoring design
parameters based on a description of the soil types encountered. Trenches should be designed by
the contractor's engineer based on site-specific geotechnical analyses. We also recommend that
if trenches are left unshored, persons be kept beyond a projection plane that the OSHA
regulations establish as the safe slope angle. In addition, adjacent utility trenches can create
instabilities if the natural soil between the trenches topples allowing the adjacent utility trench
backfill to fail. These items should be considered for trench construction. For planning
purposes, we recommend that the following OSHA soil classifications be used:
Soil Type
Fill Soils
Terrace Deposits
Santiago Formation
OSHA Soil Classification
TypeC
Type 6 above groundwater
Type C below groundwater
Type A above groundwater
Type B below groundwater
The classifications given above are for planning purposes only. The anticipated locations of
these soil types may vary significantly. Upon making the excavations, the soil classifications,
influence of adjacent utilities, and excavation performance should be confirmed by the
contractor's "Competent Person" in accordance with the OSHA regulations. Repair of damage
caused by inadequate shoring should be the responsibility of the contractor. After pipeline
construction is complete, consideration should be given for removal of shoring without damaging
the installed pipe or backfill.
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SECTIONFIVE Pipeline Design and Construction Considerations
[J
5.3.4 Dewatering
5.3.4. 1 General Conditions
Excavations are expected to require temporary dewatering during construction. Groundwater
levels should be drawn down by a dewatering system prior to excavation in order to mitigate the
potential of soil piping, heaving or boiling at the bottom of trench excavation. Dewatering
should be the sole responsibility of the contractor. The contractor should be responsible for
designing and installing a system capable of lowering and maintaining depressed groundwater
levels during construction, and the overall monitoring of dewatering effects. Estimated
dewatering rates, volumes, and equipment requirements should be determined by the contractor.
Discharge of the pumped groundwater to Agua Hedionda Lagoon may require an NPDES
permit; discharge to the existing sewer will require a permit from the Encina Wastewater
Authority. If contaminated groundwater is drawn into the dewatering system, other regulatory
issues may be faced by the CMWD, City, and the contractor with respect to pre-treatment and
discharge requirements.
Depending upon the actual location and the time of year the construction is taking place, shallow
groundwater may be encountered above and below the currently planned invert along portions of
the pipeline alignments. Areas requiring special dewatering consideration may be evaluated on a
preliminary basis based on observed groundwater conditions indicated on Figure 2.
In general, groundwater may be encountered as shallow perched water within about 5 to 1 0 feet
above the contact between the terrace deposits and the Santiago Formation. Depending on the
pipe invert elevation relative to the geologic contact, the quantity of groundwater to handle and
the feasibility of alternative methods of dewatering may vary significantly. The contractor will
have several options for dewatering techniques, including the use of sumps, well points, and deep
wells. Consideration should be made as to whether there are any nearby structures which may be
subject to dewatering-induced settlement.
For trenches where the pipe invert is less than about 2 to 3 feet below groundwater, or if the
Santiago Formation is stable against the loss of fines, or if the soils encountered are of low
permeability, stamping from within the trench (through a gravel bedding) may be a cost effective
dewatering alternative. Pumped wells or vacuum well points are suitable where larger quantities
of groundwater must be dewatered (maximum drawdown of 5 to 15 feet). Widely spaced wells
may not be effective in collecting shallow perched water above the Santiago Formation.
Cutoff systems such as cement or chemical grout may inhibit the inflow of perched water into the
excavation but may not be cost effective for the project. Use of vacuum and jet-eductor
wellpoints may also be viable. The dewatering system will be the responsibility of the contractor
and will require pipeline alignment specific information for proper design and construction.
Special consideration should be given to flowing ground conditions at the geologic contact.
Based on observations of the presence of groundwater during our field investigation, it appears
that dewatering may be necessary for significant portions of the proposed pipeline alignments.
As a guideline, the pipelines should be designed to be above the geologic contact separating the
terrace deposits from the Santiago Formation soils where ever possible.
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SECTIONFIVE Pipeline Design and Construction Considerations
It is anticipated that the terrace deposits and Santiago Formation will be sufficiently dense such
that settlement due to dewatering should be minimal. In any event, the contractor should develop
a settlement and crack monitoring plan for submittal and approval prior to dewatering. Measures
to mitigate adverse effects resulting from settlement of soils should be the responsibility of the
contractor.
5.3.4.2 Preliminary Dewatering Estimates
The following preliminary dewatering estimates for the project are based on the results of our
field explorations; groundwater monitoring well construction and development, sampling and
aquifer recovery tests; geotechnical laboratory testing; review of available site specific
hydrogeologic information; and limited dewatering analyses.
Although dewatering may be necessary over a significant portion of the alignment, our
preliminary dewatering analyses were conducted for the 4 main areas along the proposed
alignment where pumping tests were performed, and provide an overview of the conditions that
may be encountered during construction. These areas are as follows:
• Intersection of Jefferson St. and Carlsbad Village Dr. (MW-11A/B)
• Chestnut Avenue between Jefferson St. and Madison St. (MW-22A/B)
• NCTD Right-of-Way at Walnut Ave. (MW-18A/B)
• NCTD Right-of-Way at Hemlock Ave. (MW-27A/B)
Excavations during construction of these components of the project will extend below the
groundwater table. It will be necessary to dewater these areas before excavations are made in
order to reduce the possibility of soil instability and to provide a dry, firm working conditions.
Following general construction practice, we recommend depressing the groundwater to at least 5
feet below the lowest point of excavations. The groundwater must remain at such a level until
adequate building loads and integrated uplift resistance of the proposed structures to buoyant
forces can be provided.
There are two phases of site dewatering which control the regulated flow rates of pumping
discharge. The first phase (Phase I) is to force a state of active groundwater table drawdown
within the work area. The second phase (Phase II) is to maintain the level of drawdown during
the required construction period.
Preliminary estimates of construction dewatering discharge rates during Phase I for each of the
4 areas described above was performed. Phase II dewatering discharge rates for the project have
been estimated using the closed-form Theis (Theim) equation for steady state flow to an
equivalent single extraction well.
In general, our modelling of Phase I dewatering involved making assumptions pertaining to:
• Length and width of excavations
• Amount of drawdown required
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SECTIONFIVE Pipeline Design and Construction Considerations
• Configuration of multiple extraction wells
• Aquifer transmissivity variability
• Storativity
• Duration of active drawdown to required levels
For our analyses, a duration of 5 days was assumed for the active drawdown period. However,
depending on actual aquifer conditions and the number and efficiency of wells used by the
dewatering contractor, Phase I dewatering may take 10 days or longer in some areas. If Phase I
dewatering takes longer than 10 days, then the discharge rates may be significantly less than
those estimated herein.
The transmissivities calculated from the aquifer pumping and recovery were used in the
dewatering analyses. The results of our preliminary dewatering estimates for daily Phase I and II
discharges for the 4 project areas are presented in Table 2. The preliminary dewatering estimates
for Phase I and II discharges are presented herein solely for the purpose of preparing an
application for an NPDES construction dewatering permit.
Total daily discharges can be minimized by staggering dewatering activities, limiting the depths
and areas of excavations, and use of relatively impermeable cutoffs such as driven sheet pile
shoring or injection grouting. A detailed cost benefit analyses would be required to assess
whether such measures are appropriate for the project.
These estimates should not be used as the basis for designing a construction dewatering system
since they are based on very limited data. Therefore, the selected dewatering contractor should be
responsible for independently evaluating site conditions (including additional explorations);
performing long-term pumping tests (i.e., longer than 48 hours) in each area that will require
dewatering; designing and installing an operating system capable of lowering and maintaining
depressed groundwater levels during construction; and the overall monitoring of dewatering effects.
Shop drawings and schedules of all of the dewatering contractor's proposed operating systems and
activities should be submitted for review by Woodward-Clyde.
5.3.4.3 Radius of Influence and Settlements
Preliminary assessment of the potential radius of influence around extraction wells for
construction dewatering at the site was performed. In our opinion, the radius of influence due to
the construction dewatering would be on the order of 100 to 300 feet. However, depending on
variation of the actual hydraulic characteristics and hydrogeology of the project areas from those
measured in our recovery tests and observed in our borings, the extent of the groundwater
lowering due to construction dewatering could have a radius of influence up to 1,000 feet. Some
minor settlement of the ground surface within the radius of influence should be expected in areas
underlain by loose and soft materials. However, in most areas the settlement will be negligible.
Site settlements due to groundwater dewatering activities will cause an increase in effective
stresses at depth. Site settlements may be expected to be on the order of 1/4 inch for every 5 feet
of groundwater drawdown. Ground subsidence due to groundwater drawdown should be
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SECTIONFIVE Pipeline Design and Construction Considerations
monitored by the dewatering contractor. The contractor should be prepared to shore, underpin,
D or repair existing surface features that may be impacted by dewatering operations. Within the
radius of influence of dewatering wells, crack surveys should be performed before, during, and
after dewatering, and settlement monuments should be installed on settlement sensitive structures
D that are supported on shallow foundations or pavements. The crack and settlement monument
surveys should be conducted on a regular basis (i.e., weekly) up to 2 months after dewatering has
stopped. Groundwater levels should be monitored in at least two observation wells located at
[ appropriate distances from each dewatering location. However, additional observation wells
should also be installed further away from the dewatered areas and monitored regularly in order
j—l to completely evaluate the actual radius of influence of the lowered groundwater condition.
i_l
5.3.5 Trench Bedding and Backfill Materials
I Pipe bedding should consist of clean, free-draining granular material conforming to
Section 306-1.2.1 of the Green Book. We recommend that bedding material at least 6 inches
D thick should be placed below pipes up to 36 inches in diameter in order to provide uniform
support. Larger diameter pipes should have a minimum of 12 inches of bedding material. The
bedding material should extend to 12 inches above the pipe crown. Based on the results of the
r~| investigation, the majority of the native soils along the pipeline alignments may not be suitable
U for pipe bedding. Consequently, import of pipe-bedding material will be necessary.
Trench backfill may consist of native soils excavated from the trench which comply with
Section 306-1.3.1 of the Green Book. The maximum size material of the backfill should not
exceed 6 inches. The maximum size should be 2 inches for backfill in the pipe zone. Street-zone
p. backfill is the upper 36 inches of the trench immediately below the street pavement. Native soils
M may be used to backfill the street-zone, but should not have material greater than 3 inches in size.
n 5.3.6 Backfill Compaction
All backfill in the trench excavations should be compacted throughout to the specified
D requirements as described in Section 306-1.3.2 of the Green Book. Compaction of the backfill
should be achieved by mechanical or vibratory compaction equipment in order to achieve the
required compaction standard. Jetting or flooding should not be allowed to density the trench
D backfill since their effectiveness is somewhat limited in acheiving dense backfill conditions.
Pipe bedding material should be placed on each side of the pipe simultaneously to avoid
unbalanced loads on the pipe.
D A11 backfill should be moisture conditioned to, or slightly above, the optimum moisture content,•placed in lifts not exceeding 6 inches in thickness. Except for the street-zone backfill, where a
D minimum relative compaction of 95 percent will be required, other trench backfill should be
densified to at least 90 percent relative compaction. The maximum dry density and optimum
moisture content for each material used should be determined in accordance with the current
n ASTM D 1557 test procedures.
If crushed rock greater than 3/8-inch in size is used as bedding material, it should be completely
,-. wrapped in a geotextile to prevent migration of native soils into the crushed rock. The geotextile
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0
SECTIONFI YE Pipeline Design and Construction Considerations
should be placed in accordance with the provisions of the Green Book Section 300-8.1.1.
n Crushed rock backfill should be placed in accordance v/ith San Diego Regional Standard
LJ Drawing Number S-4. Type B.
r-i Mechanical compaction is generally preferred from a geotechnical perspective and should be
jj used where dewatering is maintained within the trench. However, this may require that
personnel enter the trench. Consideration may be given to the use of a 2-sack per cubic yard lean
D sand/cement slurry. The slurry could be used around the pipe to reduce both the need for
compaction and the need for personnel to enter the trench. Only nominal compaction under
direct observation is required for crushed rock backfill.
n
J 5.3.7 Trench Cutoffs
D Should areas of possible groundwater contamination be found within the alignment, trench
cutoffs may be needed to reduce the potential for migration of contaminated groundwater. Since
trench backfill is anticipated to be select material or crushed rock, these materials may tend to be
D more permeable than the surrounding native soils. As a result, the backfilled trench may become
a conduit for groundwater flows. Problems that may arise include erosion of supporting soils
around the pipe or transport of contaminants along the alignment.
(j Trench cutoffs should be spaced at intervals of approximately 400 feet to create a low
permeability barrier across the width of the trench to inhibit the migration of groundwater and
D soil piping. The cutoffs may coincide with planned manhole locations in order to simplify
design and construction. Options for trench cutoffs may include the following:
• Low strength concrete
• Compacted clay
• Sand/cement slurry
D « Soil-bentonite •
The cutoffs should be at least 12 inches wide, embedded 12 inches into the sides of the trench
G and extend at least to the top of the bedding material.
5.3.8 Pipe Loads
j Pipes should be designed for all applied loads including dead load from overburden soils, loads
applied at the ground surface, uplift loads, earthquake loads, and thrust loadings. Soil loading
pi may be estimated assuming a total density of 130 pcf for fill and backfill.
»—' Vertical and horizontal loads on a pipe caused by surface and near-surface loads may be
estimated by means of elasticity solutions. Wheel loads may be represented as concentrated
J point loads; railroad loading may be represented as line loads; and surcharges may be represented
as area loads. Estimated pipe loads caused by vehicular or railroad traffic should be increased by
n an appropriate impact factor. Impact factors typically depend on conditions at the ground surface
j j and the depth to the pipe crown beneath the soil subgrade. Pipes located below the design
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SECTIONFIVE Pipeline Design and Construction Considerations
groundwater elevations may be subject to buoyant uplift forces. However, the buoyant uplift
Fj force acting on a pipe will not likely exceed the dead weight of the soil over the pipe.
Where a pipe changes direction abruptly, resistance to thrust forces can be provided by means of
pi thrust blocks. For design purposes, the allowable passive resistance against thrust blocks may be
jj estimated using an equivalent fluid density of 350 pcf. Thrust blocks should be embedded at
least 3 feet beneath the finished ground surface and poured neatly against undisturbed
p formational materials.
0 Simplified analysis methods for estimation of the additional soil pressure that will act on pipes
during earthquake loading are not available. To reduce the risk of pipe damage that could occur
; as a result of earthquake loading, it is recommended that design vertical and horizontal loads on
pipes that result from soil dead loads be appropriately increased by the pipeline designer.
•PU 5.3.9 Erosion, Sediment and Drainage Control
,-, The potential for soil erosion is largely impacted by local soil characteristics, vegetative cover,
topographic relief, and the frequency and intensity of rainfall and wind. Removal of vegetation
and disturbance to surficial soils by construction activities may result in local increases of
B erosion rates in unprotected areas such as open trenches and stockpiled soil. As a result,
sedimentation may increase in local drainages, at site perimeters, and slope intersections.
Uncontrolled diversion of storm water along the NCTD right-of-way could result in surface
D erosion due to concentrated flow. This can result in increased turbidity of runoff to the
downstream area. We recommend that a Storm Water Pollution Prevention Plan (SWPPP) be
prepared for the project prior to construction. Woodward-Clyde can assist in the preparation of
PI the SWPPP upon request.
To reduce soil erosion and sediment transport, protective material such as gravel, crushed stone,a pavement, and other effective erosion control materials should be used to stabilize exposed soils.
Storm water runoff from construction areas should be conveyed to temporary diked detention
areas for sediment deposition, then discharged to the existing natural drainage courses at with
p velocities slow enough to prevent further erosion in the drainage courses.
'-J Control of erosion and sedimentation on recently graded construction sites require both
vegetative and structural measures. Vegetative species used to control erosion should be selected
to accommodate the soil characteristics and climate at the site. Storm runoff control should be
provided during and after completion of site grading by using diversion dikes and permanent
D drainage facilities. Sediment retention structures such as sediment basins, sediment traps or silt
fences should be used to keep eroded material on the site. Straw bales used alone, or in
combination with geotextiles, can be effective sediment retention structures when properly
P installed and maintained.
LJ
5.3.10 Pavement Restoration
[J Repaving should be based on local standards, performance evaluation, and methods used
regionally to match the existing pavement. Pavements to be removed should be saw cut prior to
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SECTIONFI YE Pipeline Design and Construction Considerations
trench excavation. Repaved sections may be prepared in accordance with the Standard Plans fornPublic Works Construction Plan No. 133-0. Asphalt Concrete Repavement Section. Three cases
are illustrated on this drawing:
D * Full asphalt section on prepared subgrade (no aggregate base)
• Aggregate base with asphalt section on prepared subgrade
• Concrete cap with asphalt overlay
y Historically, it has been our experience that restored asphalt concrete (AC) pavements over
backfilled trenches have not performed as well as pavements over continuous subgrades. We
D therefore recommend increasing the thicknesses of the restored pavement sections over that of
the existing sections. We recommend that restored pavement thicknesses be increased by 50
percent over the existing inplace sections.
n
- 5.4 MICROTUNNELLING AND PIPE JACKING
(1 5.4.1 Anticipated Microtunnelling and Pipe Jacking Areas
I I We understand that microtunnelling and pipe jacking are being considered for the following
G areas:
• Below Carlsbad Village Drive
• Below Tamarack Avenue
M • Areas within close proximity to the NCTD railroad tracks
"-* • Areas of congested existing utilities
|| However, it is our opinion that microtunnelling and pipe jacking may also be used in nearly all
^—' areas of the proposed pipeline alignments.
nU 5.4.2 Anticipated Ground Conditions and Behavior
An assessment of the ground conditions likely to be encountered along the various tunnel
j alignments was carried out to evaluate the stability of the excavations and to identify appropriate
tunnel construction methods. Ground behavior for soft ground tunnelling can be generally
,—, described according to six categories, as summarized in Table 3.
LJ Based upon a review of the range of soil conditions to be encountered, of greatest concern is the
saturated basal sands of the terrace deposits which may contain some gravel and cobbles. These
D materials are considered cohesionless sandy soils when saturated. These materials may exhibit
flowing ground conditions if not adequately dewatered or controlled with special tunnelling
equipment during excavation. These materials can also be expected to exhibit running or fast
raveling behavior even if dewatered. Flowing, raveling behavior, if allowed to occur at the
tunnel heading, can lead to significant loss of ground, and subsequent ground deformations and
,-, surface settlement. Positive construction measures would be needed to improve the behavior of
Uj the ground and to control face stability such as groundwater control or grouting. Further
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SECTIONFI YE Pipeline Design and Construction Considerations
Q ' ; ~~
discussion on ground conditions and behavior are presented in the following sections. Tunneling
D is not anticipated through fill soils.
r-j 5.4.2.1 Terrace Deposits
U The terrace deposits are considered soft ground and generally consist of friable to moderately
cemented, medium dense to very dense sandy materials. Some localized gravel and cobbles may
D be present within the terrace deposits; especially along the contact between the terrace deposits
and the underlying Santiago Formation. Under most conditions, these materials are expected to
behave as slow raveling to firm ground. Where less cemented they are expected to behave as fast
raveling to running ground. If shallow or perched groundwater conditions are present within the
sandy terrace deposits then fast raveling to flowing ground conditions may occur. Excavations
r-, are not anticipated to require immediate support unless running or flowing ground conditions are
I encountered. In general, the terrace deposits above the groundwater table should be favorable
material for all types of tunnelling including microtunnelling.
n
U 5.4.2.2 Terrace Deposits/Santiago Formation Contact
D The contact between the terrace deposits and the Santiago Formation materials is included herein
as a ground type as it has a unique bearing on the project. The contact, as revealed in our
borings, observations of the coastal bluffs from Buena Vista Lagoon to Agua Hedionda Lagoon,
D and our experience, is expected to contain relatively clean poorly graded sand (with and without
silt) with groundwater perched on top of this contact. The underlying Santiago Formation is
described below. These soils are expected to behave as flowing ground conditions. The contact
D has the potential to contain gravel and cobbles. In general, pipeline profiles along this contact
should be avoided, if possible, due to the mixed-face conditions.
D '5.4.2.3 Santiago Formation
The Santiago Formation is primarily a sandstone and siltstone unit characterized by moderately
O to highly cemented zones. This formation is expected to be saturated. As such, the formation is
expected to behave as firm to raveling ground. In the unlikely event that uncemented zones are
encountered, flowing ground could occur. If more cemented zones are encountered, it is
(~| expected to behave as slow raveling to firm ground. Although not encountered in the borings,
*~' nor observed in the adjacent sea cliff, there exists a potential for lenticular-shaped concretions
with strengths ranging from 1,000 to 10,000 pounds per square inch (psi).
LJ
5.4.3 Applicable Tunnel Excavation Methods
The terrace deposits and Santiago Formation encountered in the borings indicate anticipated
ground conditions ranging primarily from firm to raveling ground with the potential for running
p or flowing ground along with the possibility of gravel and cobbles, concretions along the contact
jj as discussed above. These ground types may require different tunnel excavation methods as
discussed below. Mixed-face conditions in which different ground types are encountered at the
Woodward-Clyde W W:\975102BA\0007-B-R.DOC\30-Jan-98\SDG 5-14
SECTIONFI YE Pipeline Design and Construction Considerations
same time are possible, especially along the contact between the terrace deposits and Tertiary
formational materials.
All tunnelling should be done with a tunnel shield using pipe jacking techniques. Pipe jacking is
,-, a technique which includes a method of excavation at the front of the pipeline with subsequent
pieces of pipe installed by jacking them into the ground from an access shaft. No trenching is
required other than to install the shafts (where needed). Larger diameter pipes (i.e., greater than
48 inches) may allow work to be done from within the pipe, if desired. Smaller diameters could
require a remotely controlled microtunnelling machine.
5.4.3.? Rotary Cutterhead Shield
A rotary cutterhead tunnelling machine could be used for all of the larger pipelines planned. This
type of tunnelling is accomplished using a rotating cutterhead which cuts the ground at the front
of the machine. An open face cutterhead may be suitable in both the terrace deposits and the
Santiago Formation. However, in running or flowing ground conditions, it should have the
capability to control ground loss. This could be accomplished by doors on the cutterhead that
are opened just enough to allow a controlled amount of soil in. In flowing ground conditions, it
may also be desirable to have a chamber behind the cutterhead, which adds to the ability to
control the ground in an Earth Pressure Balance (EPB) mode. Groundwater inflows at the face of
the machine may require use of pumps to remove the water if the tunnels are constructed down-
gradient. This type of machine is considered suitable for all of the tunnels where the pipe is large
enough for personnel entry. Consideration may be given to the use of shallow wellpoints or a
grout cutoff wall for gourndwater control. Grouting may be accomplished using a chemical
grout system.
5.4.3.2 Microtunnelling
Microtunnelling is a specialized form of pipe jacking which uses a remotely controlled, closed
face, tunnel boring machine to excavate at the heading while a lining is installed behind the
machine by pipe jacking from an access shaft. Although there is no diameter standard for
microtunnelling, the diameters typically range from about 12 inches up to about 72 inches. The
microtunnelling system has five major components: a remote control system; a microtunnel
boring machine and cutterhead; an automated spoils transportation system; a guidance system;
jj and a steering system. The selection of the microtunnelling system depends on the anticipated
*—' ground conditions, equipment availability, and costs.
The stability of the face is maintained by the EPB method. This method generally maintains the
pressure on the soil at the face between the active earth pressure to prevent settlement and the
passive earth pressure to prevent heave. Pressure should be slightly above the piezometric
groundwater pressure to prevent dewatering. Slurry could be lost in high permeability soils but
upon growth of a bentonite filter cake the overall permeability would be less. The system should
be capable of handling moderate to highly cemented sandstone, siltstone, and isolated gravels,
cobbles, and concretion zones.
W:\9751028AV0007-B-R.DOC\30-Jan-98\SDG 5-15
nu
SECTIONFI YE Pipeline Design and Construction Considerations
0
5.4.4 Frictional Resistance
Evaluation of the frictional resistance along the pipe and need for bentonite lubrication around
the pipe is dependent on the strength of the ground at the shaft and soil type along the alignment.
For the most part, the Santiago Formation soils are very dense and cemented and not likely to
experience excessively high friction unless they collapse around the pipe. The sandy soils in the
terrace deposits may collapse around the pipe and lead toward higher frictional resistance.
Dry friction of these soils may range from 0.5 to 0.8 depending on material type and strength.
However, the contractor should perform his own independent assessment of frictional resistance
based on description of soils presented here as well as equipment, lubrication, and installation
methods used. We recommend that reaction walls for installing pipe segments be designed using
an equivalent fluid weight of 350 pcf for soils that are properly dewatered.
5.4.5 Tunnel Muck Disposal
Muck resulting from tunnel and shaft excavations should be removed from the site and properly
disposed of at an acceptable location. Muck from the shaft may be suitable for reuse as
compacted shaft backfill. Slurry from microtunnelling systems should be disposed of in
accordance with local and state regulations. It may be desirable to use processed muck which
meets the requirements for select fill to raise low areas along the alignment and as backfill for
retaining structures. We anticipate that the granular terrace deposits and Santiago Formation will
be suitable for processing and reuse. It should be the contractor's responsibility to properly
dispose of the muck and slurry.
5.4.6 Settlement Estimates
Settlement is the primary source of potential damage to adjacent streets, railroad tracks, utilities,
and buildings during tunnel construction. Settlement as a result of the tunnelling operations can
develop due to the following possible causes:
• Ground loss at the heading
• Soils collapsing in the annular space around the pipe prior to grouting
• Consolidation due to dewatering
Empirical methods have been developed for estimation of surface settlement magnitudes due to
soft ground tunnelling by the study of observed settlement on past projects. Typically, the
settlement pattern that develops above a soft ground tunnel is a trough-shaped depression
resembling an inverted normal probability (bell shaped) curve, with the maximum settlement
occurring above the tunnel centerline (Peck, 1969). Our estimate of surface settlements based on
this empirical method for a range of depths is as follows:
Depth of Cover
10 feet of cover
20 feet of cover
Estimated Settlement
1/2 to 1 inch
'/itoViinch
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SECTIONFI YE Pipeline Design and Construction Considerations
The above settlement estimates assume that the proper tunnelling methods are applied to prevent
running or flowing ground conditions or uneven excavation rates in mixed face conditions with a
stabilized heading. Depending on the actual construction procedures and workmanship of the
contractor, greater surface settlement may result, if ground loss occurs and it is not monitored
and controlled. Compression of the soils as a result of dewatering is not anticipated to produce
measurable settlement. The ground is variably overconsolidated but is not expected to adversely
compress due to increased loads as a result of dewatering.
5.4.7 Shaft Construction
5.4.7.1 Shaft Geometry
For construction access during tunnel excavation and during installation of pipe, two vertical
shafts will be required, one at each end of the tunnel reaches. Shafts are usually placed 500 to
1,000 feet apart (or less) and are usually located at manholes or inlet structures. The shape and
dimensions of the shafts selected by the contractor should be compatible with the selected
construction methods and equipment and subject to review by the design engineer. Utility plans
should be reviewed for possible interference.
5.4.7.2 Excavation Stability
Shaft shoring, excavation, and dewatering considerations would be similar to those presented
previously for open-trench construction. We anticipate that the access shafts would most likely
be constructed using soldier piles and lagging with exit shafts constructed using the same method
or a trench shield. Other possible methods include liner plates and corrugated pipe. The access
shaft should be large enough to accommodate insertion of the tunnelling machine followed by
the pipe, with sufficient room for the hydraulic jacks. Shaft excavations on the order of 15 feet
by 25 feet in plan dimensions would probably be required for the pipe sizes being considered.
For stability and safety purposes, the contractor should provide and maintain during construction, a
full-perimeter shaft support system, to be installed as excavation progresses or prior to excavation.
Design of the support system will be the responsibility of the contractor, and should be based upon
the design criteria as described below. The system should be designed to penetrate a sufficient
depth to prevent bottom heave (if applicable).
5.4.7.3 Shaft Support Systems
For temporary shoring excavations in areas of level ground surface and with a maximum depth
of 30 feet, the shoring system should be designed for the earth pressures presented in
Section 5.3.3 for braced or cantilevered conditions. The pressures are based on the assumption
that the shoring system is constructed without raising the backfill area behind the walls, and that
there are no surcharge loads acting above a 1:1 plane extending up and back from the base of the
wall.
Driven steel sheet pile shoring may be possible through the terrace deposits; vibratory methods
may not be possible. However, driven steel sheet piles may only be able to penetrate a few feet
Woodward-Clyde W W:\9751028A\0007-B-R.DOC\30-Jan-98\SDG 5-17
SECTIONFI YE Pipeline Design and Construction Considerations
into the Santiago Formation. Another option is to use stacked trench boxes backfilled with
gravel on a slurry mix. The contractor should be responsible for the design of short support
systems.
5.4.7.4 Shaft Groundwater Control
Groundwater control will be required to construct the shaft excavations for the access and exit
shafts. Combinations of dewatering (predrainage), sumps within the excavation, and
groundwater cutoffs may need to be utilized. Dewatering well options to be considered include
deep wells and wellpoints in the more pervious soil strata. Appropriate filters and screen sizes
M should be provided to prevent the removal of fines from the silty deposits that will otherwise
^ occur during pumping. The design of dewatering systems and the performance of field pumping
tests to support those designs should be the responsibility of the contractor.
5.4.8 Jacking Pipe Design Considerations
Pipe selection for use with microtunnelling/pipe jacking depends on the requirements for internal
pressure, jacking forces, and corrosion resistance. The approach allows for directly jacking the
pipe, which is the most cost effective method. Based on anticipated conditions and conceptual
project alternatives, direct jacking is the preferred method of construction. These pipes have
uniform outside diameters with no protruding bells and must be capable of resisting jacking
loads as well as ground loads. The annular space between the pipe and ground should be
lubricated with bentonite or polymers, and the pipe installation completed by contact grouting
around the pipe.
Concrete pipes to be installed using pipe jacking methods must satisfy several important criteria
including those presented in Section 300-2 of the Green Book. The jacking pipe should be
designed for the maximum axial compressive stresses to be exerted on the pipe during jacking,
stress concentrations, earth loads due to the full overburden pressure, and groundwater pressure.
The contractor is responsible for final design of the jacking pipes, taking into account the stresses
C that the pipe will be subjected to during installation. We recommend that reaction walls for
installing pipe segments be designed using an equivalent fluid weight of 350 pcf for soils that are
properly dewatered.
Fabrication of the pipe to stricter tolerances than is normally required will be warranted to avoid
stress concentrations at the pipe ends. The contractor should coordinate with the pipe
manufacturer to establish tolerance requirements and any special tolerances required to avoid
I damaging the pipe during installation. The pipes should be provided with threaded grout fittings
for contact grouting the annular void space between the pipe and the surrounding ground.
5.4.9 Instrumentation and Monitoring
j-. Existing conditions should be documented prior to construction and should consist of a
If reconnaissance and survey of all pavements, sidewalks, structures, and any other improvements
Woodward-Clyde W W:\9751028A\0007-B-R.DOC\30-Jan-98\SOG 5-18
SECTIONFI YE Pipeline Design and Construction Considerations
within 100 feet of the pipeline centerline. Photo documentation and the survey will serve as an
aid in evaluating possible damage due to settlement resulting from the tunnelling operations.
To monitor surface settlement during construction, a survey system of vertical control points
should be established prior to construction, and elevations should be surveyed periodically
during construction in accordance with specified intervals. Five survey points should be spaced
every 25 feet along the tunnel alignment, at the tunnel centerline and offset 20 and 40 feet on
either side where possible. Modified survey point locations and any additional required control
points should be determined during construction in accordance with the specifications.
Monitoring should consist of measuring the elevation of each of the survey points with respect to
a benchmark to an accuracy of ±0.01 foot.
Groundwater observation wells should be installed to monitor groundwater levels if dewatering
methods are used for groundwater control during construction.
5.5 INLETS AND ACCESS HOLES
I Inlet structures and access holes will be incorporated into the project along the pipelines.
Construction of the these structures may be done from within an open excavation. Anticipated
soil and excavation characteristics for these locations are as discussed for the tunnel shafts or the
open trench construction sections of this report. In general, the soil conditions are anticipated to
include shallow fills running a sequence of upper terrace deposits overlying the Santiago
Formation. It should be noted that borings and CPTs performed for this investigation may not be
located adjacent to proposed inlets and access holes. Therefore, additional explorations may be
warranted in the locations of the these special structures.
5.5.1 Foundation Preparation
All of the inlet and access hole structures are anticipated to be underlain by competent soils. The
primary consideration for design and construction of these structures will include the following:
„ • Preparation of a uniform surface to place the structure on.
• Preparing the surface where groundwater is seeping into the excavation.
5.5.1.1 Structures Above Groundwater
Where the structure is underlain by terrace deposits above the groundwater, the structure may be
placed on dense undisturbed formational soils or a 12-inch thick mat of recompacted select fill if
loose or disturbed materials are encountered. Terrace deposit soils are anticipated to meet the
requirement of select fill and thus can likely be reused. Select fill should be compacted to a
minimum relative compaction of 90 percent when tested in accordance with ASTM D1557.
Foundations supported on prepared subgrade, as described above, may be designed using a
maximum allowable soil bearing pressure of 3,000 psf for dead plus live loads. Estimated total
I settlement for mat foundations described above may be expected to be on the order of 1/2 inch or
less.
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SECTIONFIVE Pipeline Design and Construction Considerationso
5.5.12 Structures Below Groundwater
M For the condition where the bottom of the structure is located below groundwater level, it may be
^ advantageous to prepare the foundation using an alternative approach. We anticipate that
P-, excavations made below groundwater will have seepage entering the excavation even if the
contractor installs a dewatering system. The critical consideration will be to prepare a stable mat
of soil at the same time that groundwater is seeping into the excavation. Under this condition,
r-> we recommend that a 12-inch thick mat of crushed rock wrapped in filter fabric be used as it
U does not require compaction and facilitates removal of groundwater.
The bottom of the excavation should be prepared by excavating to firm material. Groundwater
I seeping into the excavation should be allowed to flow into a gravel filled sump located at least 3
feet from the footprint of the access hole. The seepage should be removed from the sump with
r-, pumps and either directed down the trench away from the work area or removed from the trench
and routed externally as allowed by water discharge regulations. If groundwater is heaving the
bottom of the excavation, then dewatering wells will likely be needed to control the heave.
D Foundations supported on prepared subgrade, as described above, may be designed using a
maximum allowable soil bearing pressure of 2,000 pounds per square foot (psf) for dead plus live
loads. Estimated total settlement for mat foundations described above may be expected to be on the
j order of 1/2 inch or less.
n 5.5.2 Lateral Earth Pressures
U We have assumed that the walls for the access holes are considered restrained from lateral
movement and that they will not be drained such that groundwater can build up behind the wall if
it is below the groundwater level.
For static loading conditions above the groundwater level, we recommend that an equivalent
0 fluid pressure of 35 pcf plus a uniform pressure of 10H psf (where H is the height of the structure
in feet) be used for the lateral earth pressures on the wall. Below the static groundwater level, we
recommend an equivalent fluid pressure of 20 pcf plus a uniform lateral earth pressure of 5H psf.
O A groundwater pressure -of 62.4 pcf should also be added to the lateral earth pressures. An
additional uniform lateral pressure of 400 psf should be used in design to account for an HS20
truck loading. Where the structure is located below the groundwater level, it should be analyzed
\ for hydrostatic uplift.
For earthquake shaking considerations, we do not recommend any increase in the lateral earth
D pressures as it is anticipated that the structure will move with the ground. We do not anticipate
the need for passive earth pressures or coefficients of friction along the bottom of the structure as
their are no unbalanced lateral loads to resist.n
5.5.3 Backfill Recommendations
D Structures should be backfilled with compacted native soils or with 3/8-inch crushed rock. Soils
should be placed in 12-inch maximum loose lifts and compacted to 90 percent relative
compaction in accordance with ASTM D1557. At the contractor's option, backfilling may beD •
Woodward-Clyde W W\9751028A\0007-B-R.DOC\30-Jan-9mSDG 5-20
SECTIOHFIVE Pipeline Design and Construction Considerations
done with crushed rock larger than 3/8-inch but with a geotextile placed between the crushed
rock and the ground. Shoring should be removed as the backfill is brought up.
5.5.4 Storm Drain Slope Anchors and Outlet Headwall
Reinforced concrete slope anchors should be used to mitigate the potential axial creep of the
storm drain pipeline in the steeply descending slope area adjacent to Agua Hedionda Lagoon. In
general, concrete slope anchors may be similar to what is shown in the San Diego Regional
Standard Drawings Drawing No. S-9. However, we recommend that minimum extended
penetrations beyond the trench depths and widths be 24 inches. A positive annular connection
between the pipe and the concrete anchor should be provided. Minimum spacing of the concrete
anchors should be on the order of 50 to 100 feet down the slope.
Recommendation for preparation of the foundation zone for the storm drain outlet headwall is
presented in Section 5.2.3 of this report. The storm drain outlet headwall footing should be at
least 12 inches wide and 18 inches deep into properly compacted fill or undisturbed dense
formational soils. The footing should be designed for a maximum allowable bearing pressure of
3,000 psf. This pressure may be increased by one-third for loads that include earthquake forces.
Settlements are expected to be on the order of less than % inch.
Lateral earth pressures for headwalls should be based on active earth pressures due to compacted
select fill soils behind a cantilever retaining wall system. Select backfill should be sandy soil and
should have 100 percent passing the 3/4-inch screen, no less than 60 percent passing the No. 4
sieve, and no more than 10 percent passing the No. 200 sieve. The following equivalent fluid
weights may be used to estimate the lateral earth pressures exerted against a cantilever retaining
wall for static load conditions:
Backfill Slope
(H:V)
Level
2:1
13/4:1
114:1
Equivalent Fluid Weight
(pcf)
35
45
50
70
The earth pressures presented above assume that select soil will be used as backfill, that there
will not be surcharge loads acting on the wall, and the wall will be provided with backfill drains
to prevent the buildup of excess hydrostatic pressures. To include the effect of additional lateral
pressure caused by temporary loads placed behind the wall, we recommend that the wall be
designed for an additional lateral pressure equal to 0.3q where q is the intensity of the surcharge
loading.
We recommend that the outlet headwall for the storm drain be fronted with a rip-rap energy
dissipator in accordance with San Diego Regional Standard Drawing D-40 and the Standard
Specifications for Public Works Construction Standard Special Provisions Section 200-1.6.
Woodward-Clyde W:\9751028A\0007-B-R.DOC\30-Jan-98\SDG 5-21
SECTIOHFIVE Pipeline Design and Construction Considerations
Tidal variations within Agua Hedionda Lagoon may be expected to be on the order of -3 to +3
feet MSL. Exceedance of this range may occur on rare occasions. It is not anticipated that the
tidal effects will significantly impact the stability of the base of bluff near the location of the
outlet headwall. However, proper construction techniques in this area will lessen potential
impacts, if any.
Woodward-Clyde 90 W:\9751028A\0007-B-R.DOC\30-Jan-98\SDG 5-22
SECTIONS IX Uncertainty and limitations
We have observed a limited portion of the subsurface and groundwater conditions in the proposed
project areas. The recommendations made herein, except where specifically noted otherwise, are
for design purposes and are based on the assumption that soil conditions do not deviate appreciably
from those found during our field investigations. In particular, descriptions of subsurface materials
and groundwater conditions are couched with emphasis on pertinent characterizations required for
project analyses, design, and construction. However, inherent variability of these conditions are
possible.
We recommend that our firm conduct a review of the project plans and specifications to verify that
the intent of the design recommendations presented in this report have been properly interpreted
and incorporated into the construction documents. If variations or undesirable geotechnical
conditions from these described in this report are encountered during construction, we should be
consulted for further recommendations. This report is intended for design purposes only and may
not be sufficient to prepare an accurate bid. The contractor is encouraged to perform his own
independent exploration and testing prior to the start of construction.
California, including Carlsbad, is an area of high seismic risk. It is generally considered
economically unfeasible to design structures to resist earthquake loadings without damage.
Proposed pipeline structures designed in accordance with our recommendations could experience
limited distress/damage if subject to strong earthquake shaking.
This firm does not practice or consult in the field of safety engineering. We do not direct the
contractor's operations, and we cannot be responsible during construction for the safety of
personnel other than our own on the site; the safety of others is the responsibility of the contractor.
The contractor should notify the owner if he considers any of the recommended actions presented
herein to be unsafe.
Professional judgments presented herein are based partly on our understanding of the proposed
construction, and partly on our general experience. Our engineering work and judgments rendered
are consistent with current professional standards. We do not guarantee the performance of the
project in any respect.
Woodward-Clyde V W:\9751028A\0007-B-R.DOC\30-Jan-98\SDG 6-1
SiCTIONSEVEN References
Berger, V. and Schug, D., Probabilities Evaluation of Seismic Hazard in the San Diego-Tijuana
Metropolitan Region in Environmental Perils, San Diego Region, Abbo H, P.L. and
Elliott, W.J., editors.
Eisenberg, L.I. 1983. Pleistocene marine terrace and Eocene geology, Encinitas and Rancho
Santa Fe quadrangles, San Diego County, California: San Diego State University
Master's Thesis (unpublished), 386 p.
Eisenberg, L.I. 1992. "Pleistocene Faults and Marine Terraces, Northern San Diego County" in
The Regressive Pleistocene Shoreline, Annual Field Trip Guide Book No. 20; South
Coast Geological Society, Inc.
Hannan, D.L. 1975. "Faulting in the Oceanside, Carlsbad, and Vista Areas, Northern San Diego
County, California," in Studies on the Geology of Camp Pendleton. and Western San
Diego County. California. San Diego Association of Geologists, pp. 56-59.
Heuer, R.E. 1974. "Important Ground Parameters in Soft Ground Tunneling," in Subsurface
Exploration for Underground Excavation and Heavy Construction. ASCE, New York,
NY, pp. 41-55.
Kern, P.J. 1977. Origin and history of upper Pleistocene marine terraces, San Diego, California.
Geol. Soc. Amer. Bull. 88, pp. 1533-1566.
Peck, R.B. 1969. "Deep Excavations and Tunneling in Soft Ground," Proceedings,
7th International Conference on Soil Mechanics and Foundation Engineering, State of the
Art Volume, pp. 225-290.
jj Peck, R.B., Hendron, A.J., and Mohraz, B. 1972. "State of the Art of Soft Ground Tunneling,"
1st Rapid Excavation and Tunneling Conference, Vol. 1, American Society of Civil
Engineers; American Society of Mining, Metallurgical and Petroleum Engineers, pp. 259-
286.
Terzaghi, K. 1950. "Geologic Aspects of Soft Ground Tunneling," Chapter 11 in Applied
Sedimentation, ed. P. Trask, John Wiley and Sons, New York, NY, pp. 193-209.
Treiman, J.A., 1993. The Rose Canyon Fault Zone, Southern California, California Division of
Mines and Geology, Open Fire Report 93-02.
Weber Jr., F.H., 1982. "Recent Slope Failures, Ancient Landslides, and Related Geology of the
North-Central Coastal Area, San Diego County, California," California Department of
Mines and Geology, Open-File Report 82-12 LA, 76 pp.
Woodward-Clyde V W:\9751028M0007-B-R.DOC\30-Jan-98\SDG 7-1
Table 1
SUMMARY OF HYDROPUNCH GROUNDWATER SAMPLE ANALYTICAL RESULTS
CARLSBAD-VISTA SEWER/STORM DRAIN
(All constituents reported in mg/1, unless otherwise noted)
Sampling
Location
C-3
C-6
C-10
C-16
C-21
C-29
Sample
Depth
(feet)
25-35
12-17
12-17
5-15
5-15
13-18
Date
Collected TRPH* VOCs" PCBs'
8/20/97
8/21/97
8/20/97
8/21/97
8/21/97
8/20/97
<1
<1
<1
<1
<1
<1
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
SVOCs*
Bis(2-ethylhexyl)phthalate
9ug/l
ND
ND
ND
ND
ND
Title 22 Priority Pollutant Metals*
Chromium
<0.1
0.6
0.4
0.7
<0.1
0.3
Copper
<0.1
<0.1
<0.1
<0.1
<0.1
0.1
Lead
<0.1
0.1
<0.1
0.1
<0.1
0.2
Nickel
<0.1
0.2
0.1
0.1
<0.1
<0.1
Zinc
<0.1
0.4
0.3
0.8
<0.1
0.3
Mercury
0.0001
0.0009
0.0005
0.0008
<0.0001
0.0008
Selenium
0.004
<0.03
<0.03
0.04
<0.003
<0.03
Notes
* Total recoverable petroleum hydrocarbons by EPA Method 418.1.
b Volatile organic compounds by EPA Method 8260; no VOCs were detected at the detection limits specified on the laboratory data sheets.
° Poly chlorinated biphenyls by EPA Method 8080; no PCBs were detected at the detection limits specified on the laboratory data sheets.
dSemivolatile organic compounds by EPA Method 8270; no other SVOCs were detected at the detection limits specified on the laboratory data sheets.
* No other metals were detected at the detection limits specified on the laboratory data sheets.
ND: Not detected at the detection limit specified on the laboratory data sheets.
The symbol " < " (less than) indicates the constituent was not detected at the specified analytical detection limit.
W:\S751028A\CB-VIS-1 MS
C=3 cm
Table 2
SUMMARY OF CONSTRUCTION DEWATERING ESTIMATES
CARLSBAD/VISTA SEWER/STORM DRAIN
Dewatering
Area
MW-11A/B
MW-18A/B
MW-22A/B
MW-27A/B
Approximate
Location
(Station)
75+ 15 to 75+30
44+20 to 44+35
13+40 to 13+55
21+70 to 21+85
Assumed
Drawdown
Required
(feet)
8
10
6.0
12
Assumed
Length of
Dewatering
Area1(feet)
100
100
100
100
Assumed
Width of
Dewatering
Area2(feet)
7
7
7
7
Range of
Calculated
Transmisslvities
(m'/day)
0.22 to 50.9
0.54 to 25.4
2.07 to 99
0.72 to 42.8
Calculated
Storitivity
(unitless)
3.2 E-02
7.8 E-02
6.9 E-02
4.6 E-02
Estimated Time
to Initially
Dewater
(days)
5
5
5
5
Estimated Range
of Daily Discharge
Rates- Phase I
(GPM)
30-50
90-120
240-300
150-190
Estimated Range
of Daily Discharge
Rates- Phase 2
(GPM)
20-30
50-70
120-150
80-100
Notes:
1: For estimating purposes it was assumed that 100 foot lengths of excavation would be dewatered at one time
2: For estimating purposes it was assumed that the trench width would not exceed 7 feet
W:\97S 1028AW3-T3 JO.SV1/3WM
Table 3
CATEGORIES OF GROUND CONDITIONS FOR SOFT GROUND TUNNELS
(After Terzaghi, 1950 as Modified by Heuer, 1974)
Firm Ground - A heading may be advanced several feet or more without immediate support.
Hard clays and cemented sand or gravel generally fall into this category.
Squeezing Ground - Squeezing ground conditions are analogous to plastic flow, and the soil is
observed to advance slowly into the tunnel excavation without any signs of fracturing.
Squeezing occurs without an increase in the water content or a volume change in the soil and is
governed by the soil strength in comparison to the overburden pressure. Squeezing ground
may include soft to medium stiff or stiff clays depending on the overburden pressure at the
tunnel depth.
Swelling Ground - A condition where the ground absorbs water, increases in volume and
expands slowly into the tunnel. This may occur in highly overconsolidated clays that exhibit
high volume change characteristics upon wetting.
Raveling Ground - After excavation, material above the tunnel or in the upper part of the
working face tends to flake off and fall into the heading. In fast raveling ground, the process
starts within a few minutes, otherwise the ground is slow raveling. Slightly cohesive sands,
silts, and find sands gaining their strength from apparent cohesion typically exhibit this type of
behavior. Very stiff fissured clays may be raveling materials also.
Running Ground - Cohesionless, dry soils run from any unsupported vertical face until a stable
slope forms at the natural angle of repose (i.e., approximately 30 degrees to 35 degrees).
Running ground consists of dry, cohesionless materials, such as clean loose sand or gravel.
Flowing Ground - If seepage develops at the working face, raveling or running ground is
transformed to flowing ground, which advances like a viscous fluid into the heading. Silt, sand,
or gravel below the water table without a high enough clay content to develop significant
cohesion will be flowing-type soils.
2000 4000
•APPROXIMATE GRAPHIC SCALE
(FEET)
BASE MAP:
USGS 7.5 MINUTE SAN LUIS REY QUADRANGLE
LEGEND
INDICATES APPROXIMATE LOCATION
OF PROPOSED SEWER AND STORM
DRAIN ALIGNMENTS
VICINITY AND ALIGNMENT MAP
VISTA/CARLSBAD SEWER/STORM DRAIN
FN:DRAWN BY: CM CHECKED PROJECT NO: 9751028A-0007 DATE: 10-22-97 FIGURE NO: 1
WOODWARD-CLYDE
LEGEND
REPORTED EARTHQUAKE MAGNITUDES.NATIONAL FOR MARINE CORPS BASE*'^.V VALLEY \
3.0 TO 3.9
CD 4.0 TO 4.9
5.0 TO 5.9
^GABRIEL
MOUNTAINS
THOUSAND
OAKS
O 7.0 AND GREATERANACAPA
SLAND
EPICENTER,AND;MAGNITUDE DATA ARE FROM
THE CALTECH EARTHQUAKE CATALOG FOR THE
PERIOD FROM 1800 TO 'DECEMBER 1991, WITH
THE 1992 JOSHUA TREE, LANDERS, AND BIG
BEAR, AND 1994.NORTHRIDGE EVENTS ADDED.
ONLY EARTHQUAKES OF MAGNITUDE 3.0
AND LARGER ARE SHOWN.
APPROXIMATE FAULT LOCATIONS, DOTTED
WHERE CONCEALED, QUERIED WHERE
coWEeryAL FAULT LOCATIONS BASED
ON: ZlONY AND : JONES, 1989: GEOlJOGtC
MAP SERIES OF CALIFORNIA, 1977-1986
(1:25Q;QQO SCALE); GEQUOGIC-MAP SERIES.
CAUFORNlA CONTINENTAL MARGIN, 1986-1987
(1:250,000 SCALE); HAUKSSON. 1990; AND
WRIGHT, 1991.
\
SANTA BARBARA
ISLAND \
CATALJNA
ISLAND CEANSIDE
CARLSBAD
ESCONDIDO
CINITAS
SAN CLEMENTE
ISLAND
' c o o
CD o CD e
REGIONAL FAULT AND EPICENTER MAP
VISTA/CARLSBAD SEWER/STORM DRAINAPPROXIMATE GRAPHIC SCALE
(MILES)
DRAWN BY: CM FIGURE NO: 3
118-15' 11BW 11745 DATE: 10-31-97 [PROJECT NO: 9751028A-0007
WOODWARD-CLYDE
APPENDIKA Soil Boring logs
D
D
Woodward-Clyde W:\9751028AVXXJ7-A-R.DOC\31-Oct-97\SDG
iV
D
n-u
C
DATE
STARTED
HAMMER
WEIGHT (Ibs)
DATE TOTAL DEPTH DIAMETER OFFINISHED DRILLED (feet) BORING (inches)
HAMMER GROUNDWATER DATE
DROP (inches) DEPTH (feet) MEASURED
DRILLING DRILLING
COMPANY EQUIPMENT
DRILLING BOREHOLE
METHOD BACKFILL
LOGGEDBY
APPROXIMATE SURFACE BORING
ELEVATION (feet, MSL) LOCATION
Q- flj
Q
5-
.
10-
-
-
_
15-
-
-
20-
25-
30-
-
-
-
35-
"-•
40-
-
LU
0.
^£
C/3
V
M
T1
•*-*
»4—c/5
5o^j
CD
O
|o
U—o
'• hi
DESCRIPTION
DISTURBED SAMPLE
Sample was obtained by collecting cuttings in a bag or sack
DRIVE SAMPLE LOCATION
Sample with recorded blows per foot was obtained by using a
Modified California drive sampler (2" inside diameter, 2-1/2"
outside diameter). The sampler was driven into the soil with a 140
pound hammer falling 30 inches.
STANDARD PENETRATION SAMPLER
Sample with recorded blows per foot was obtained by using a
standard split spoon sampler (1-3/8" inside diameter, 2" outside
diameter). The sampler was driven into the soil with a 140 pound
hammer falling 30 inches.
-
NX CORE SAMPLER
Sample was obtained by using a triple-tube core barrel (2-1/8"
inside diameter, 3" outside diameter) equipped with a
diamond-impregnated coring bit.
-
Fill
Sand
Sand/Silt
Silt
ABBREVIATIONS
SA( ) - Sieve Analysis (% passing #200 sieve)
LC( ) - Laboratory Compaction (MOD in pcf/OMC in %)
DS( ) - Slow Direct Shear test (phi, C in psf)
UNC( ) - Unconfined Compression test (psf)
pH( ) - pH result
Perm( ) - Permeability test (range of permeability, cm/s)
Res( ) - Resistivity test (ohm-cm)
SS( ) - Water Soluble Sulfates (%)
SC() - Water Soluble Chloride (%)
OVA( ) - Organic Vapor Analyzer (ppm)
ATD - At time of drilling
SH
1|*OoSo
«_-
occn'C
LLJo
OTHER
TESTS/
NOTES
Project: Vista/Carlsbad Sewer/Storm Drain Figure A- 1
Project Number: 9751028A-0002 LOG OF BORING KEY 1 of T
11W978GLOG 1028A Woodward-Clyde
CTARTED 8^^
HAMMER 1JAWEIGHT (Ibs) 14°
DATE arte/or TOTAL DEPTH ^,FINISHED »'•»"'' DRILLED (feet) **-3
HAMMER ,0 GROUNDWATER None encounteredDROP (inches) 30 DEPTH (feet) None encountered
DIAMETER OF fiBORING (inches) 8
DATE ATDMEASURED Alu
DRILLING T • rn..ntv n,;n:n» DRILLING p^rp 7eCOMPANY Tri-County Drilling EQUIPMENT CMt/ 75
r\DTT T TWf DfiDCI-IfM P
MCTHOD Hollow stem auger BACKFILL Rentonite grout LOGGED y Wittig
^TFVA^oNT^JUi^nCE 65-5 LOCATION Sta. 113+50 Jefferson Streetd*CV/\llW11 \ICd, XVlJLt) LAJ^rJ\ 1 1WJ1!
Q- 43LLJH-
Q
5-
1 nI \J
-
.
1 C_
I O
-
_
20-
;
25-
30-
-
-
40-
C/3LU
O_
2
<C/3
2-2 y
2-3 ^
2-4 L
2-5 ^,
2-6 f
J
2"7 ^
2-8 ^
2"9 h OWS/ft_jCD
15
29
71
73
79
85
87
Ui§DESCRIPTION
. FILL
\4" asphalt concrete over moist, brown sand with fine gravel
Moist, brown, silty fine sand
_
TERRACE DEPOSITS
Medium dense, moist, yellowish red, silty fine SAND (SM) to
very fine poorly graded SAND with silt (SP-SM) and trace clay
and fine gravel
I Becomes light yellowish brown, poorly graded medium to
fine SAND with silt (SP-SM); slightly more moisture (not
A wet) f-
SANTIAGO FORMATION
Medium dense, moist, light gray, silty medium to very fine SAND
(SM) to very stiff, fine sandy SILT (ML); weakly cemented, trace
v medium to coarse sand ,"~
Very dense to hard, moist, light gray, silty medium to fine SAND "
(SM) to fine sandy SILT (ML)
-
Very dense, moist, light gray, silty medium to fine SAND (SM)
with trace clay ;-
Very dense, moist, light gray, silty medium to fine SAND (SM)
with trace coarse sand
t With trace clay; faint light brown and olive zones
Very dense, moist, light yellowish brown, silty medium to fine
_^SAND (SM)
Bottom of boring at 34.5 feet
-
Sb
H^oS;HS?
OQ
8
13
11
11
11
>
ccwtj
Q
106
107
120
125
123
OTHER
TESTS/
NOTES
SA(16)
LC(127.5/9.5)
pH(6.9)
Res(1136),SS(0.014)
SC(0.004),OVA(0)
SA(ll)
OVA(O)
SA(23)
OVA(O)
SA(27)
OVA(O)
SA(20)
OVA(O)
OVA(O)
OVA(O)
Project: Vista/Carlsbad Sewer/Storm Drain Figure A-2
Project Number: 9751028A-0002 LOG OF BORING B-2 i of 1
11/4/97 BGLOG 1028*Woodward-Clyde
DATE 8/1C/Q7STARTED olOiiyi
HAMMER ,j«WEIGHT (Ibs) 1W
DATE «/«/Q7 TOTAL DEPTH ^ „FINISHED XUSly' DRILLED (feet) **•"
HAMMER ,ft GROUNDWATER ,<-
DROP (inches) 30 DEPTH (feet) 10
DIAMETER OF „
BORING iinches) 8
DATE ATnMEASURED Alu
DRILLING T • Cn..ntv n-iilim* DRILLING rME 7SCOMPANY Tri-County Drilling EQUIPMENT uvm 7S
METHOD0 Hollow stem auger BACiaSif Bentonite grout LOGGED y wjttig
APPROXIMATE SURFACE «_ BORING Sta 88+44 lefferson StreetELEVATION (feet, MSL) 55'5 LOCATION «a. H»+ 44 Jefferson Street
E-t" ®a. <t>UJ»-
Q
5-
10-
15-
onZU
25-
onOt)
35-
40-SAMPLES8-1 k
8-2 k
8-3 y
)
8-4 k
8-5 k,
8-6 L
8-7 ^
8-8 ^BLOWS/ft19
36
39
39
SO/4"
50/6"
50/4"GRAPHICLOGDESCRIPTION
FILL
4" asphalt concrete over moist, brown, sand and gravel base
TERRACE DEPOSITS
Medium dense, moist, reddish brown, silty medium to very fine
-SvyND (SM)
Becomes yellowish brown
Dark brown layer with trace fine gravel
^ ~ Becomes dense, moist, brown to olive brown, poorly graded
fine to very fine SAND with silt (SP-SM)
f. Becomes dense, wet, poorly graded medium to fine SAND
^ (SP) with trace silt and coarse sand
-, SANTIAGO FORMATION
\Dense, wet, gray, silty fine SAND (SM)
Hard, moist, light yellowish brown, sandy SILT (ML) moderately "
cemented siltstone
r Silty fine SAND (SM) interbeds
* Less consolidated (weakly cemented) SILT (ML)
Very dense, moist to wet, light yellowish brown, silty medium to
fine SAND (SM) with trace clay and coarse sand
Bottom of boring at 34 feet MOISTURECONTENT,L %10
10
18
20
15
13
>t~occoo
Q2tt
LU
Q
109
107
107
109
118
118
OTHER
TESTS/
NOTES
SA(25)
OVA(O)
SA(ll)
OVA(O)
SAP)
DS(45/350)
SA(70)
UNC(7574)
SA(55)
SA(19)
UNC(49)
Project: Vista/Carlsbad Sewer/Storm Drain Figure A-3
Project Number: 9751028A-0002 LOG OF BORING B~8 1 of 1
11M/97BGLOG 1028A Woodward-Clyde
STARTED si any i
HAMMER ,-nWEIGHT (Ibs) lsv
DATE unman TOTAL DEPTH « tFINISHED oiattyj DRILLED (feet) <j:>-:>
HAMMER ,ft GROUNDWATER ,dDROP (inches) •su DEPTH (feet) **
DIAMETER OF sBORING (inches) 8
DATE
MEASURED
DRILLING -. rn,tntv nrillJno DRILLING rMF 7fCOMPANY Tri-County Drilling EQUIPMENT UVUi 75
METHOD0 Hollow stem auger BACKFIL^ Bentoriite grout
ATD
LOGGED y wittig
APPROXIMATE SURFACE ..; _ BORING Ste -_ , »- Ieffer!on StreetELEVATION (feet, MSL) 56'5 LOCATION &». 75 + 85 Jefterson Mreet
Q_ 4)
Q
1 nI U
"-
-
15-
"
_
OA2\J
-
-
-
35-
-
40-AMPLESC/3
11-1
11-2
11-3
11-4
11-5
11-6
11-7
11-8
11-9
X
^
X
M
H
M
•^
M LOWS/ftm
45
34
50/3"
120/6"
50/4"
69/6"
52/6"RAPHICLOGu
i i i
DESCRIPTION
. FILL
'. 4" asphalt concrete over moist, grayish brown, sand and gravel
'base ,' -
"\Moist, reddish brown, fine sand with sUt 'f-
TERRACE DEPOSITS
Dense, moist, yellowish red, silty fine to very fine SAND (SM) to
poorly graded medium to very fine SAND with with silt (SP-SM)
"-
-
I With some brownish gray interbeds with less silt and faint
orange staining
-
2
—
SANTIAGO FORMATION
Very dense, wet, light olive gray, silty medium to fine SAND
(SM); trace fine rounded gravel in cuttings
-
Very dense, wet, light gray, poorly graded medium to fine SAND
with silt (SP-SM)
-
Very dense to hard, moist, light grayish brown, clayey fine to
very fine SAND (SC) to sandy SILT (ML), moderately cemented
siltstone with fine sand
Very dense, light grayish brown, silty medium to very fine SAND
(SM), weakly to moderately cemented sandstone
-
-\Hard, moist, light grayish brown SILT with fine sand (ML) /-
Bottom of boring at 35.5 feet
-OISTUREDNTENT,%50
4
5
17
15
14
13
LLJ
Q
105
103
114
109
116
118
OTHER
TESTS/
NOTES
SA(15)
OVA(O)
DS(42/120)
SA(7)
LC( 134. 0/8.0)
OVA(0)
SA(14)
OVA(0)
SA(10)
Perm(1.3xE-5 to
4.9xE-5)
SA(40)
UNC(7670)
SA(17)
Project: Vista/Carlsbad Sewer/Storm Drain
Project Number: 9751028A-0002 L°G OF BORING B-1 1
Figure A-4
1 of 1
11/4/97 BGLOG 1028A Woodward-Clyde
STARTED *™W
HAMMER 1<ftWEIGHT (Ibs) lsv
DATE Rne/07 TOTAL DEPTH ^ nFINISHED 0/25/97 DRILLED (feet) 34-u
HAMMER ,n GROUND WATER lft eDROP (inches) J0 DEPTH (feet) IV'5
DIAMETER OF »BORING (inches) 8
DATE *TTkMEASURED AIU
COMPANY Tri-County Drilling ggS?ENT CME 7S
MCTHOD0 Hollow stem auger BAOOTLlf Bentonite grout LOGGED y W|ttig
APPROXIMATE SURFACE „ - BORING § 64 + 40 Oak AvenueELEVATION (feet, MSL) */>:) LOCATION sul- vt^'w waK Avenue
E«-1— 0)Q_ flj
W"-Q
5-
10-
1 KI O
•7r\zu
25-
^r*JU
35-
40-SAMPLES14-1 r
}
14-2 k
14-3 k
14-4 ^
14-5 >:
14-6 E
14-7 fc
14-8 E BLOWS/ft(
^ 21
~A 30
^ 50/5"
^ 50/3"
3 107/6"
4 SO/
4.5"
i 50/3"GRAPHICLOGDESCRIPTION
^ FILL r\4" asphalt concrete over 3" sand and gravel base / ~
TERRACE DEPOSITS
Medium dense, moist, reddish brown, silty fine to very fine
SAND (SM)
Becomes yellowish red
V Becomes dense, wet, light olive gray ~
SANTIAGO FORMATION
Very dense, moist, light yellowish brown, clayey fine to very fine
SAND (SC); weakly cemented
Hard, moist, light yellowish brown, sandy SILT (ML) to very
dense, moist, silty medium to very fine SAND (SM)
^ Becomes poorly graded medium to fine SAND with silt ~
(SP-SM)
Hard, moist, light yellowish brown SILT with fine sand (ML)
Bottom of boring at 34 feet MOISTURECONTENT,%17
21
14
11
12
>
>t«-CCOJO
QZtt
LUQ
104
106
118
125
119
OTHER
TESTS/
NOTES
SA(25)
OVA(0)
SA(17)
OVA(O)
SA(46)
OVA(0)
SA(17)
UNC(21321)
OVA(O)
SA(ll)
OVA(0)
Project: Vista/Carlsbad Sewer/Storm Drain Figure A- 5
Project Number: 9751028A-0002 LOG OF BORING B-14 1 Qf 1
I1/4ra? BGLOG I028A Woodward-Clyde
STARTED 8/22/97
HAMMER ,-„WEIGHT (Ibs) l:>u
DATE «m/Q7 TOTAL DEPTH w fFINISHED »'•"'=" DRILLED (feet) JH-:'
HAMMER -.A GROUNDWATER 1ft .DROP (inches) iV DEPTH (feet) 1U'3
DIAMETER OF «
BORING (inches) 8
DATE ATT.
MEASURED Alu
cffi&Y Tri-County Drilling BQUffMENT ^^ 75
MCTHOD0 Hollow stem auger BACIOTLlf Bentonhe grout LOGGED y W|ttig
APPROXIMATE SURFACE 4, _ BORING Sta 47+30 NCTD R O WELEVATION (feet, MSL) 41'5 LOCATION Ma. 47 + JU INC11J K.U.W.
fcl
Q
5-
10-
_
15-
20-
25-
_
30-
-
35-
40-AMPLESc/)
17-1 r\1
17-2 k
17-3 L
17-4 r
17-5 ^
17-6 E
17-7 fc
17-8 E
17-9 SB LOWS/ften
i
4 2S
J 23
/I
^ 50/5"
3 157/6"
3 130/6"
"200/2"
i 240/6"
(J
1°DC
CJ
DESCRIPTION
-v FILL r-
\Dry to moist, brown, silty sand /
TERRACE DEPOSITS
Medium dense, dry to moist, yellowish red, silty fine SAND (SM)
-
2 — Becomes brown to olive gray, wet, poorly graded fine to very
^ fine SAND with silt (SP-SM)
'
.
—
SANTIAGO FORMATION
Very dense, moist, light yellowish brown, silty medium to very
fine SAND (SM)
_
-
Very dense, moist to wet, light yellowish brown, silty medium to
very fine SAND (SM) with interbeds of hard SILT (ML) and trace "
clay
| Interbedded silts and sands ~
;
Bottom of boring at 34.5 feet
-OISTUREDNTENT,%2u
8
19
20
19
12
ocw'o
02 °-LLt
O
111
101
110
123
OTHER
TESTS/
NOTES
LC(135.0/7.5)
SA(23)
OVA(O)
SA(12)
DS(39/200)
pH(7.3),Res(1470)
SS(0.015)
SC(0.014)
OVA(l)
SA(18)
Perm(1.2xE-5 to
1.7xE-5)
OVA(O)
SA(18)
SA(17)
UNC(1547)
Project: Vista/Carlsbad Sewer/Storm Drain Figure A-6
Project Number: 9751028A-0002 LOG OF BORING B-17 1 of 1
UM/97 BGLOG 1028*Woodward-Clyde
STARTED' 8/26/97
HAMMER 1JnWEIGHT (Ibs) 1W
DATE on<iivi TOTAL DEPTH 70 cFINISHED *U*lyl DRILLED (feet) *y's
HAMMER ,n GROUNDWATER QDROP (inches) •*" DEPTH (feet) y
DIAMETER OF sBORING (inches) 8
DATE ATnMEASURED Alu
DRILLING r-. rn.,ntv rh-ill!«o DRILLING rME 75COMPANY Tri-County Drilling EQUIPMENT UVUi 75
METHOD3 Hollow stem auger/NX coring BACKFIuf B«rt°nhe grout LOGGED y WHtig
^T^J-'JSST ".« ISSSoN Sta.l3+20 Chestnut Avenue
£«0. vLU>«-
Q
5-
1 ATO
15-
20-
OKzo
onoU
35-
40-SAMPLES22- 1 L
22-2 \
)
22-3 k
22-4 *:
Run 1
22-5 £
22-6 ^
22-7 BLOWS/ft4 19
/
f 27
3 78/6"
3 57/6"
4 50/3"
! 159/6"GRAPHICLOGDESCRIPTION
FILL
4" asphalt concrete over sand and gravel base
TERRACE DEPOSITS
Medium dense, moist, yellowish red, silty medium to very fine
SAND (SM) to poorly graded fine to very fine SAND with silt
J~(SP-SM)
Becomes brown with faint orange staining
¥
Medium dense, wet, dark olive gray, poorly graded medium to
fine SAND (SP) with mica
Very dense, wet, light olive gray, poorly graded coarse to fine
_^SAND (SP) with trace silt and fine rounded gravel
SANTIAGO FORMATION
Hard, dry to moist, grayish brown, SILT with fine sand (ML),
moderate cementation
Very dense, moist, grayish brown, clayey fine to very fine SAND
(SC)
Bottom of boring at 29.5 feet MOISTURECONTENT,%6
23
12
17
15
>
>t^OCOTOQ2 Q.
LUQ
106
101
119
115
116
OTHER
TESTS/
NOTES
SA(17)
LC(133.0/8.5)
OVA(O)
SA(2)
Perm(2.1xE-3 to
2.5xE-3)
OVA(0)
SA(1)
OVA(O)
SA(72)
SA(42)
UNC(5975)
Project: Vista/Carlsbad Sewer/Storm Drain Figure A-7
Project Number: 9751028A-0002 LOG OF BORING B-22 1 Qf 1
11/4/97 BGLOG 1028A Woodward-Clyde
STARTED 8/22/07 DATEFINISHED
TOTAL DEPTH
DRILLED (feet)
DIAMETER OFBORING (inches)
HAMMER
WEIGHT (Ibs)1jn1W HAMMERDROP (inches),ft30 GROUNDWATER
DEPTH (feet)1ft10 DATEMEASURED
Tri-County Drilling CME 75
MCTHOD3 Hollow stem auger/NX coring KFILjf Bentonite «r°vtBACKFILj
LOGGED y Wittig
Sta. 34+82 NCTDR.O.W.SAMPLESBLOWSGRAPHICLOGDESCRIPTION
MOISTURECONTENT,%DRYNSITYpcfOTHER
TESTS/
NOTES
24-1
10-24-2
40
26
29
TERRACE DEPOSITS
Medium dense, dry to moist, yellowish red, silty fine SAND (SM)
112
V Becomes wet with dark gray discolored zones 14 105
SA(25)
OVA(O)
SA(16)
OVA(0)
Dense, wet, light brown, poorly graded medium to fine SAND
1 c _| i i (SM) to micaceous, olive brown, poorly graded fine to very fine10 i 24-3 Q 31 SAND with silt (SP-SM) 26 96 SA(7)
OVA(O)
24-4 ^1100/6" SANTIAGO FORMATION j 16 111 SA(26)
Very dense, moist to wet, light grayish brown, silty fine to very j OVA(0)
fine SAND (SM)
OC—J ____- -.3 ' 24-5 M 50/5" | IIJI Very dense to hard, moist, light grayish brown, clayey fine to J SA(39)
very fine SAND (SC) to sandy SILT (ML), moderately cemented " 16 ]16 UNC(6797)
30 ' 24-6 M138/6"
Very dense, wet, light gray, silty fine SAND (SM)
Run 1 |~| M-t-M--Hard, wet, light gray SILT (ML)
NR II ;:;:;:;:;: Very dense, wet, light gray, silty fine SAND (SM)
Run 2 If l'l I Hard, wet, light gray, SILT (ML) with greenish discoloration and
red staining at 35'; siltstone contains trace fine to medium sand
Bottom of boring at 38.5 feet
Project: Vista/Carlsbad Sewer/Storm Drain
Project Number: 9751028A-0002 LOG OF BORING B-24
Figure A-8
, Qf 1
11/4/97 BGLOG 1028*Woodward-Clyde
DATE an 1/07STARTED »'•"«"
HAMMER 14nWEIGHT (Ibs) 1W
DATE an 1/07 TOTAL DEPTH .meFINISHED XWy' DRILLED (feet) w-3
HAMMER ,n GROUNDWATER ,,
DROP (inches) JU DEPTH (feet) ll
DIAMETER OF fiBORING (inches) 8
DATE ATDMEASURED Alu
DRILLING T . r-lltlt_, n-siu__ DRILLING rMF 7eCOMPANY Tri-County Drilling EQUIPMENT UVUl 75
MEraOD5 Hollow stem auger/NX coring BACKFIL^ Bentonite »«>«*LOGGED y WJttig
APPROXIMATE SURFACE *•% - BORING cta 21-t-flfl WTD R O WELEVATION (feet, MSL) 4Z'5 LOCATION «a. ZJ + UW INC1L» K.U.W.
0. OJLUH-Q
5-
10-
15-
;
25-
30-
"3Coo
40-SAMPLES27-1 k
27-2 &
27-3 k
27-4 fe
27-5 fc
27-6 ^
27-7
27-8 x
Run 1 BLOWS/ft12
19
50/4"
50/3"
113/6"
136/6"
143/6"
127/3"GRAPHICLOGDESCRIPTION
TERRACE DEPOSITS
Medium dense, dry to moist, yellowish red, silty medium to fine
SAND (SM)
| ~ Becomes brown
i Gray cuttings
V
| Becomes wet with reddish orange staining
SANTIAGO FORMATION
Very dense, wet, gray, poorly graded medium to very fine SAND
with silt (SP-SM) with orange red staining
Very dense, moist to wet, light gray, silty medium to fine SAND
(SM) with trace of coarse sand and fine graded gravel
Very dense, wet, gray, well graded medium to fine SAND with
silt (SW-SM); weak cementation, little cohesion
Very dense to hard, wet, light gray, silty medium to fine SAND
(SM) to sandy SILT (ML)
Very dense, wet, gray, moderately cemented clayey medium to
fine SAND (SC)
Softer clayey zone
Bottom of boring at 40.5 feet MOISTURECONTENT,%6
18
13
15
17
16 DRYDENSITY,pcf113
122
115
OTHER
TESTS/
NOTES
SA(22)
OVA(O)
OVA(0)
SA(10)
Perm(1.5xE-5 to
3.4xE-5)
OVA(l)
SA(32)
UNC( 10594)
OVA(l)
SA(8)
SA(16)
SA(43)
Project: Vista/Carlsbad Sewer/Storm Drain Figure A-9
Project Number: 9751028A-0002 LOG OF BORING B-27 -j of -j
11M/97 BGLOG 1028A Woodward-Clyde
STARTED 8/21/97
HAMMER ljnWEIGHT (Ibs) 14U
DATE a/,, /0- TOTAL DEPTH ^4-FINISHED oftllyt DRILLED (feet) •M'-:'
HAMMER ,n GROUNDWATER -,* e
DROP (inches) M DEPTH (feet) ^-3
DIAMETER OF aBORING (inches) 8
DATE ATnMEASURED Alu
COMPANY Tri-County Drilling EQUIPMENT CME 75
METHOD3 Hollow stem auger BACKJTljf Bento""** grout LOGGED y wjttig
APPROXIMATE SURFACE ,o - BORING Kta , , , ,n MrTn n r> WELEVATION (feet, MSL) iy'5 LOCATION ata' ll + M ™-"> K.U.W.
O. 0)UJ*^
Q
~
51
-
10-
-
15-
.
20-
-
25-
-
30-
"
35-
~
-
40-
enHI
0.
2
C/5
30-1 k
30-2 V)
30-3 L
30-4 ^
30-5 L
30-6 T
30-7 T
30-8 ^
30-9 L
£
CO
O
CO
15
27
33
38
52
42
29
O
%tro
DESCRIPTION
TERRACE DEPOSITS
Medium dense, dry to moist, reddish brown, silty medium to fine
SAND (SM)
f Becomes yellowish red
,
-,
i, Becomes light brown with reddish orange staining, poorly
graded fine to very fine SAND with silt (SP-SM)
-
1 Dense to very dense, moist, light yellowish brown, silty fine to
very fine SAND (SM)
_
>- Thin, light grayish brown, sandy SILT (ML) lens
Becomes poorly graded fine SAND (SP)
-
>~ Thin olive brown SILT (ML) lenses
| Faint orange staining
-
SANTIAGO FORMATION
Medium to very dense, moist, light gray to light olive gray, poorly
graded fine to very fine SAND with silt (SP-SM)
i Becomes wet, micaceous olive, poorly graded fine to very
» fine SAND with silt (SP-SM)
Bottom of boring at 36.5 feet
-
UJ -
005o
6
7
5
4
5
30
>-
crw'C
LU
O
109
99
94
100
94
91
OTHER
TESTS/
NOTES
SA(21),OVA(0)
pH(7.5)
Res(3474)
SS(O.Oll)
SC(0.002)
SA(ll)
OVA(0)
SA(22)
DS(44/0)
OVA(0)
SA(3)
OVA(O)
SAP)
OVA(O)
SA(7)
OVA(O)
SA(8)
Project: Vista/Carlsbad Sewer/Storm Drain Figure A-10
Project Number: 9751028A-0002 LOG OF BORING B-30 ., Qf 1
11/4/97 BGLOG 1028A Woodward-Clyde
DATESTARTED 8/22/97
HAMMER ldnWEIGHT (Ibs) IW
DRILLING
COMPANY
DRILLING
METHOD
FINISHED 8/22/97
HAMMER ,nDROP (inches) JO
Tri-County Drilling
Hollow stem auger
APPROXIMATE SURFACE ^ ,
ELEVATION (feet, MSL) JO'3
E~(- a>a. CDUJ«*-
Q
10-
15-
on^u
OKzo
•3r»oU
35-
40-SAMPLES33-1
33-2
33-3
33-4
33-5
33-6
33-7
1
a
bg
B BLOWS/ft51
19
50/4"
50/3"
67/6"
81/6"
72/6"GRAPHICLOGJli
TOTAL DEPTH ^ ,
DRILLED (feet) >>-:>
GROUNDWATER „
DEPTH (feet) **
DIAMETER OF 8BORING (inches) 8
DATE
MEASURED ATD
DRILLING rMF 7cEQUIPMENT *-mr/ /s
BACKFILL6 Bentonite grout LOGGED y Wittjg
LOCATION Sta' °"1"30 NCTD R-°'W-
DESCRIPTION
- FILL
\Dry, light brown to browri, silty and
Dry to moist, reddish brown, fine sand with silt
Moist, brown to dark bro\
silly fine sand, possibly sc
« — -, Becomes yellowish b
~\ Clay "balls" within s;
vn, weakly to moderately cemented,
me perched-water
rown
Mid matrix f
TERRACE DEPOSITS
Medium dense, moist, light brownish gray, silty fine to very fine
SAND (SM) weakly to moderately cemented, with reddish orange
staining (localized).
» Becomes very dense, clayey fine to very fine SAND (SC)
Very dense, moist, light yellowish brown, silty fine to very fine
SAND (SM)
Very dense, moist, h'ght brownish gray, clayey medium to very
fine SAND (SC)
Very dense, moist to wet, light brownish gray, silty fine to very
fine SAND (SM) with trace clay
g !
SANTIAGO FORMATION
~\ Very dense to hard, wet, light gray
\fine to very fine SAND (SM) to san
-
moderately cemented clayey /I
dy SILT (ML) /
Bottom of boring at 34.5 feet
Project: Vista/Carlsbad Sewer/Storm Drain
Project Number: 9751G28A-0002 MOISTURECONTENT,%13
14
9
6
14
CCflo
QZa
LLJ
0
104
112
103
106
OTHER
TESTS/
NOTES
OVA(O)
SA(35)
OVA(0)
SA(45)
OVA(O)
SA(32)
OVA(O)
SA(48)
OVA(O)
SA(31)
LOG OF BORING B-33 Figure A- 11
1 of 1
11M/97 6GLOG 1028A Woodward-Clyde
APPEKDIXB OPT Soundings
Woodward-Clyde W:\9751028A\0007-A-RDOC\31-Oct-97\SDG
31
C
03
CTD era en c±) CD C3 cm cr? CD c=r a
EGG WOODWARD CLYDE Site : CARLSBAD SEUER S/D
Location : C—1
Engineer : S. PRICE
Date : 08: 20:97 11:
Qt (tsf)
-0.0
-5.0
.c -10.0
Q.QJQ
-15.0
-20.0
Fs (tsf)
500 0 15
Haiidajigered
Max. Depth: 43.14 (ft)
Depth Inc.: 0.164 (ft)
U (psi) Rf (%)
0 100 0.0 5.0 0 12
1
andaugered Handaxigered
MINIMI Silly Sand/Sand
Sandy Silt
Silt
Sandy Silt
Silty Sand/Sand
Sand
Silty Sand/Sand
Sand
Silty Sand/Sand
Sand
Sandy Silt
Clayey Silt
Sandy Silt
Silty Sand/Sand
Sand
Silty Sand/Sand
Sand
SBT: Soil Behavior Type (Robertson and Campanella 1988)
en co en en CD en en
Q.(UQ
3!ca°c
3
CD
WOODWARD CLYDE Site : CARLSBAD SEUER S/D
Location : C-1 .
Engineer : S. PRICE
Date : 08: 20: 97 1 1:
-22.4
Qt (tsf) Fs (tsf) U (psi) Rf (%) SBT
0 500 0 15 0 100 0.0 5.0 0 12
i
-27.4
-32.4
-37.4
-42.4
Max. Depth; 43.14 (ft)
Depth Inc.: 0.164 (ft)
IT Silly Sand/Sand
Sandy Silt
Silt
Sandy Silt
Clayey Silt
Clay
Silly Clay
Clayey Silt
Silly Clay
Clayey Silt
Silly Clay
Clayey Sill
Stiff Fine Grained
Clay
Clayey Sill
Silly Clay
Stiff Fine Grained
Cemented Sand
Sandy Sill
Sliff Fine Grained
Clayey Silt
Clay
SBT: Soil Behavior Type (Robertson and Campanella 1988)
WOODWARD CLYDE Site : CARLSBAD SEWER S/D
Locat i on : C-3
Engineer : S. PRICE
Date : 08:20:97 14:
Qt (tsf)
-0.0
-5.0
.c -10.0
D.QJQ
-15.0
-20.0
~nc5'
DO
O>
500
Max. Depth; 34.78 (ft)
Depth Inc.: 0.164 (ft)
Haridajigered
\ '
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
I
andaugered Iferidapgered
IIII INI I I Silty Sand/Sand
Sandy Silt
Silty Sand/Sand
Sandy Silt
Silty Sand/Sand
Silly Sand/Sand
Sand
Silty Sand/Sand
Silt
Cemented Sand
Stiff Fine Grained
SBT: Soil Behavior Type (Robertson and Campanella 1988)
cri
EGG WOODWARD CLYDE Site : CARLSBAD SEUER S/D
Location : C-3
Engineer : S. PRICE
Date : 08:20:97 14:57
0
Qt (tsf) Fs (tsf)
500 0 15
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
-22. A
-27. A
-32.4
o_mQ
-37.4
-42. A
Stiff Fine Grained
<ac
OJ
Max. Depth: 34.78 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
C3
Q.
CDQ
-nto'c
DO
WOODWARD CLYDE Site : CARLSBAD SEUER S/D
Location : C-4
Engineer : S. PRICE
Date : 08:21:97 12:23
Qt (tsf)
-0.0
-5.0
-10.0
-15.0
-20.0
Fs (tsf)
500 0 15
Handavigered
Max. Depth; 12.96 (ft)
Depth Inc.: 0.164 (ft)
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
M
aridaugered >Iandaygered
1 1 1 1 1 1 1 1 1 1
v
2, :
*'*•i' ' i
i.
"7
Sensilive Fines
Sandy Sill
Silly Sand/Sand
Sandy Sill
Silly Sand/Sand
Sandy Sill
Silly Sand/Sand
Sand
Silly Sand/Sand
Sand
SBT: SoU Behavior Type (Robertson and Campanella 1988)
CTD CO CD
-n<S
DO
O)
aajQ
-0.0
-5.0
WOODWARD CLYDE Site : CARLSBAD SEUER S/D
Location : C-4A
Engineer : S. PRICE
Date : 08:21:97 13:09
Qt (tsf)
500
Haiida gered
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
I
andaugered
Silly Sand/Sand
Sandy Silt
Silly Sand/Sand
Sandy Sill
Silly Sand/Sand
Sandy Sill
Silly Sand/Sand
Sandy Sill
Silly Sand/Sand
Sand
Silly Sand/Sand
Cemented Sand
Sliff Fine Grained
Cemenled Sand
Sandy Sill
Cemented Sand
Stiff Fine Grained
Cemented Sand
Stiff Fine Grained
imented Sand
Max. Depth: 23.62 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
C3 cn
WOODWARD • CLYDE Site : CARLSBAD SEWER S/D Engineer : S. PRICE
Location : C-4A Date : 08:21:97 13:09
0
Qt (tsf) Fs (tsf)
500 0 15
U (psi)Rf (%)SBT
0 100 0.0 5.0 0
-22. A
-27 .A
-I-J
£ -32.4
aIDo
-37.4
-42.4
-n
COc3
CD
1 1 1 1 ! T — t— -1 1
Max. Depth: 23.62 (ft)
i i i i | i i rN I I
SBT: S
1 1 1 1 { 1 J-f 1
•
Cemented Sand
ail Behavior Type (Robertson and Campanella 1988)
Depth Inc.: 0.164 (ft)
CD-CD
Q
CO
§
CD
CD
WOODWARD CLYDE Site : CARLSBAD SEUER S/D
Location : C-6
Engineer : S. PRICE
Date : 08:21:97 07:55
Qt (tsf)Fs (tsf)
0 500
U (psi)
0 100
Rf (%)SBT
0.0 5.0 0 12
-0.0
-5.0
-10.0
-15.0
-20.0
Handajigered Handavgered andaugered Harjldapgered
TTTIT11 Sensitive Fines
Sill
Sandy Silt
Silt
Sandy Silt
Silt
Sandy Silt
Silly Sand/Sand
Sandy Silt
Silty Sand/Sand
Sand
Sandy Silt
Silty Sand/Sand
Sand
Silty Sand/Sand
Sandy Silt
Cemented Sand
Stiff Fine Grained
Sandy Silt
Silt
Stiff Fine Grained
Max. Depth: 27.23 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
11
co
§
CD
CD
GREGG
0
OO /IC.I— . L\'
-27 .A
+jo_
jz -32.4+->Q.03Q
-37.4
-42.4
WAnnWATDDi r1! Vni? Site : CARLSBf^D SEUER S/D Engineer : S. PRICEVVUUUVVAKU LLYUt Locatlon : c_6 Date . 08=21=97 07: 55
Qt (tsf) Fs (tsf)
500 0 15
1 1 1 K, 1 1 1 1 1 MM) I'>--L 1
U (psi)
0 100 0.
1 I MINIMI
Rf (%)
0 5.
i i i i | i i i i
<
0 C
SBT
12
^^^^nrnT
•^H
Stiff Fine Grained
Cemented Sand
Max. Depth; 27.23 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
en CD CD CD CD
WOODWARD CLYDE Site : CARLSBAD SEUER S/D Engineer : S. PRICE
Location ; C-7 Date : 08:21:37 11:07
Qt (tsf)
-0.0
-5.0
-10.0
D.03Q
-15.0
-20.0
(0
3
Fs (tsf)
500 0 15
Max. Depth; 19.52 (ft)
Depth Inc.: 0.164 (ft)
Haiidaugered
U (psi) Rf (%) SET
0 100 0.0 5.0 0 12
audaugpred
Silt
Sandy Silt
Silty Sand/Sand
Sandy Silt
Silty Sand/Sand
Sandy Silt
Cemented Sand
Sandy Silt
Silty Sand/Sand
Sand
Silty Sand/Sand
Sand
Gravelly Sand
SET: Soil Behavior Type (Robertson and Campanella 1988)
Qt (tsf)
WOODWARD CLYDE .
Fs (tsf)
Site : CARLSBAD SEUER S/D Engineer : S. PRICE
Location : C-9 Date : 08:21:97 14:
-0.0
£4-
Q.Q)Q
TI
to'c3
CD
500 0 15
Max. Depth: 32.15 (ft)
Depth Inc.: 0.164 (ft)
Handafigered
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
I
andaugered Haridaijigert Clayey Silt
Silt
Sandy Silt
Cemented Sand
SBT: Soil Behavior Type (Robertson and Campanella 1988)
D.
<DQ
Tl<5'c
S
CD
CID C3
WOODWARD CLYDE Site : CARLSBAD SEUER S/D
Location : C-9
Engineer : S. PRICE
Date : 08: 21: 97 14: 14
Qt (tsf)Fs (tsf)
0 500 15
U (psi)
0 100
Rf (%)
0.0 5.0
SBT
-27.4
-32.4
-37.4
-42.4
IT TT mented Sand
Stiff Fine Grained
Cemented Sand
Stiff Fine Grained
Cemented Sand
Stiff Fine Grained
Cemented Sand
Stiff Fine Grained
Max. Depth: 32.15 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
en en
o_0)Q
(O
I
CO
to
WOODWARD CLYDE
Qt (tsf)
Site : CARLSBAD SEUER S/D Engineer : S. PRICE
Location : C-10 Date : 08:20:97 O7: 56
0
Fs (tsf)
500 0 15
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
-0.0
-5.0
-10.0
-15.0
-20.0
Haridafigered llaiida{igered
IT
iandaugered
Clayey Silt
Silt
Sandy Silt
Silt
Sandy Silt
Silt
Cemented Sand
Stiff Fine Grained
Cemented Sand
Silty Sand/Sand
Sand
Silty Sand/Sand
Cemented Sand
Silty Sand/Sand
Sand
Silty Sand/Sand
Cemented Sand
Stiff Fine Grained
Silt
Sandy Silt
Silly Sand/Sand
Cemented Sand
Sandy Silt
Max. Depth; 24.28 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
(QC
o>
CO
0
OO A
-27.4
£ -32.4
aCDQ
-37.4
-42.4
WOODWARD CT YDF site : CARLSBAD SEUER S/D Engineer : s. PRICE
Location : C-1O Date : 08:20:97 07:56
Qt (tsf) Fs (tsf)
500 0 15
,^^
I I I IH-J-I I 1
U (psi)
0 100 0.
1 1 1 1 1 1 1 1 M 1
Rf (%)
0 ' 5.
1 1 1 1 I<MI 1
0 C
SBT
) 12
Sandy SUt
Cemented Sand
Silly Sand/Sand
Max. Depth: 24.28 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
en
Q.0)O
TI<5'
i
CO
WOODWARD CLYDE Site : CARLSBAD SEUIER S/D
Location : C-12
Engineer : S. PRICE
Date : 08:21:97 14:51
Qt (tsf)
-0.0
-5.0
-10.0
-15.0
-20.0
Fs (tsf)
500 0 15
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
Handa igered Jidaugered Halida^igered
I I I I II Sensitive Fines
Silt
Silly Sand/Sand
Sandy Silt
Sand
Cemented Sand
Stiff Fine Grained
Cemented Sand
Stiff Fine Grained
Max. Depth: 16.57 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
cm CID GZD cm CD CID CD cn CID cn en
EGG WOODWARD CLYDE Site : CARLSBAD SEUIER S/D
Location : C—13
Engineer : S. PRICE
Date : 08:21:97 15:50
Qt (tsf)
500
-0.0
-5.0
-10.0
a
03a
-15.0
-20.0
31<a'
i
CO_^en
Max. Depth: 14.60 (ft)
Depth Inc.: 0.164 (ft)
U (psi)
0 100
Rf (%) SBT
0.0 5.0 0 12
andaugered
Sensitive Fines
Silt
Sandy Silt
Silt
Sandy Silt
Silt
Stiff Fine Grained
Silly Sand/Sand
Sandy Silt
Sand
Silly Sand/Sand
Sandy Silt
Stiff Fine Grained
SBT: Soil Behavior Type (Robertson and Campanella 1988)
WOODWARD CLYDE Site : CARLSBAD SEUIER S/D Engineer : S. PRICE
Location : C-13A Date : 08:21:97 16:11
Qt (tsf)
-0.0
-5.0
-10.0
aOJa
-15.0
-20.0
-n<&c
3
03
a>
Fs (tsf)
500 0 15
Max. Depth: 15.26 (ft)
Depth Inc.: 0.164 (ft)
U (psi) Rf (%) SBT
0 100 0.0 5.0 0
Sand
Sandy Silt
Silt
Sandy Silt
Silly Sand/Sand
Stiff Fine Grained
SBT: Soil Behavior Type (Robertson and Campanella 1988)
CD CD CD CD CD CD CD CD CD CD
(Q
C
3
03
WOODWARD CLYDE
Qt (tsf)
500
Fs (tsf)
0 15
-22.4
-27.4
.c -32.4+->a03o
-37.4
-42.4
: CARL9BAD 9EUIER S/D Engineer : S. PRICE
tion : C-15 Date : 08:21:97 16:39
U (psi) Rf (%) SBT
C
1
) 1C
ft r-t-r-
0 0.0 5.
i i i i i i i i i
^
oo i;
1 minimi
•
«»
183
s-
^^S
->
Stiff Fine Grained
Sandy Silt
Silty Clay
Stiff Fine Grained
Clay
Stiff Fine Grained
Silt
Cemented Sand
Stiff Fine Grained
Silt
Max. Depth: 34.12 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
en czi CZD CZD CZ) CZ)
-nco'c
3
03
oo
GG WOODWARD CLYDE Site : CARLSBAD SEWER S/D Engineer : S. PRICE
Location : C-15 Date : 08:21:97 16:39
Qt (tsf)
-0.0
-5.0
.c -10.0
aCDa
-15.0
-20.0
Fs (tsf)
500 0 15
Handa gered
Max. Depth: 34.12 (ft)
Depth Inc.: 0.164 (ft)
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
andaugtered Handa gered
nrm lilt
Sandy Sill
SUt
Sandy Sill
Silt
Sandy Silt
Silt
Sandy Silt
Silly Sand/Sand
Sandy Silt
Silly Sand/Sand
Sliff Fine Grained
Sandy Sill
Silt
Stiff Fine Grained
Sill
Sandy Sill
Silt
Cemented Sand
Stiff Fine Grained
SET: Soil Behavior Type (Robertson and Campanella 1988)
dD dD dD czn dD dD dD
CQ
I
03
acua
WOODWARD CLYDE Site : CARLSBAD SEUER S/D
Location : C-16
Engineer : S. PRICE
Date : 08: 18: 97 14: 37
Qt (tsf)
500
-0.0
-5.0
-10.0
-15.0
-20.0
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
IT
_
Cemented Sand
Stiff Fine Grained
Clayey Silt
SUt
Sandy Silt
Silt
Stiff Fine Grained
Sandy Silt
Silly Sand/Sand
Sandy Silt
Cemented Sand
Stiff Fine Grained
Cemented Sand
Silly Sand/Sand
Cemented Sand
Stiff Fine Grained
Cemented Sand
Fine Grained
ited Sand
Max. Depth: 22.31 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
LZD
COc
CD
DO
NJ
O
CL
03
Q
EGG
-o.o
-5.0
-10.0
-15.0
-20.0
WOODWARD CLYDE Site : CARLSBAD SEUIER S/D Engineer : S. PRICE
Location : C-18 Date : 08:18:97 14:03
Qt (tsf)Fs-(tsf)
500 0 15
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
Sandy Silt
Sand
Cemented Sand
Stiff Fine Grained
Silt
Sandy Silt
Sandy Silt
Stiff Fine Grained
Sandy Silt
Silly Sand/Sand
Sandy Silt
Silly Sand/Sand
Cemented Sand
Stiff Fine Grained
Max. Depth: 18.37 (ft)
Depth Inc.: 0.164 (ft)
SET Soil Behavior Type (Robertson and Campanella 1988)
a
Q)Q
31toc
S
CO
to
EGG WOODWARD CLYDE Site : CARLSBAD SEUER S/D
Locat i on : C- 1 9
Engineer : S. PRICE
Date : O8: 18: 37 13: 21
Qt (tsf)Fs (tsf)U (psi)
-0.0
-5.0
-10.0
-15.0
-20.0
500 0 100
Rf (%)
0.0 5.0
SBT
12
I T I Sensitive Fines
Sandy Sill
Cemented Sand
Stiff Fine Grained
Clayey Silt
Silt
Sandy Silt
Cemented Sand
Sandy Silt
Silt
Sandy Silt
Silt
Sandy Silt
Silt
Sandy Silt
Silt
Stiff Fine Grained
Silly Sand/Sand
Sandy Silt
Silly Sand/Sand
Sand
Silly Sand/Sand
Sand
Silly Sand/Sand
Sliff Fine Grained
Max. Depth: 21.33 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
cm
EGG
Q.QJQ
-n
CO
toN3
. WOODWARD CLYDE
Qt (tsf)
Site : CARLSBAD SEUER S/D
Location : C—2O
Engineer : S. PRICE
Date : 08: 19: 97 12: 48
U (psi)
0 100
-0.0
-5.0
-10.0
-15.0
-20.0
I I I I I I I I
PREPUNCHED
MINIMI
REPUNf HED
I I I I I I IPREPUNCHED
Rf (%) SBT
0.0 5.0 0 12
I I I I I I I I I
PREPUNCHED Undefined
Sand
Silty Sand/Sand
Sandy Silt
Silt
Sandy Silt
Silty Sand/Sand
Silt
Sandy Silt
Silty Sand/Sand
Sand
Silty Sand/Sand
Sand
Cemented Sand
Sandy Silt
Silty Sand/Sand
Max Depth; 19.03 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
en
EGG
Q.
0)
Q
-q<5'
i
DO
Mw
WOODWARD CLYDE Site : CARLSBAD SEUIER S/D
Location : C-21
Engineer : S. PRICE
Date : 08: 19: 97 1 1: 40
Qt (tsf)
0
-0.0
-5.0
-10.0
-15.0
-20.0
i i i i I i i iPREPUNCHED
Max. Depth: 16.24 (ft)
Depth Inc.: 0.164 (ft)
Fs (tsf)
500 0 15
U (psi) Rf (%) SBT
0 100 0.0 5.0 0
i i i i i i i i i
PREPUNCHED
11
I
1 1 1 1 1 II 1 1'REPUNCiHED Organic Soil
Clay
Sand
Silly Sand/Sand
Sand
Silly Sand/Sand
Sandy Sill
Sliff Fine Grained
Clayey Sill
Sandy Sill
Silly Sand/Sand
Sandy Sill
Sill
Clayey Sill
Sandy Sill
Cemented Sand
SBT: Soil Behavior Type (Robertson and Campanella 1988)
to
i
CD
Q.03Q
EGG WOODWARD CLYDE Site : CARLSBAD SEUER SxD
Location : C-23
Engineer : S. PRICE
Date : 08: 19: 97 14: 53
Qt (tsf)Fs (tsf)
-0.0
-5.0
-10.0
-15.0
-20.0
500 15
i \r \i\\\\
PREPUNCHED
Max. Depth: 29.04 (ft)
Depth Inc.: 0.164 (ft)
U.(psi)
0 100
Rf (%)
0.0 5.0
SBT
0 12
I i I I I I I I I I
TREPUNflHED
I I I I I I I IPREPUNCHED
I
TTTTTnill I Undefined
Silty Sand/Sand
Sandy Silt
Silty Sand/Sand
Sand
Silty Sand/Sand
Sandy Silt
Sand
Sandy Silt
Silt
Clayey Silt
Stiff Fine Grained
SBT: Soil Behavior Type (Robertson and Campanella 1988)
WOODWARD CLYDE Site : CARLSBAD SEUIER S/D
Location : C-23
Engineer : S. PRICE
Date : 08:19:97 14:53
Qt (tsf)
0
Fs (tsf)
500 0 15
-22.4
-27.4
-32.4
o_
<DQ
-37.4
-42.4
3!(Q
C3
CD
tocn
Max. Depth: 29.04 (ft)
Depth Inc.: 0.164 (ft)
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
TT I I I I I I I I Stiff Fine Grained
Silt
Sandy Silt
Silt
Cemented Sand
SBT: Soil Behavior Type (Robertson and Campanella 1988)
aQ)o
(0c
cm cm czn en
EGG WOODWARD CLYDE
Qt (tsf)
Site : CARLSBAD SEUER S/D Engineer : S. PRICE
Location : C-25 Date : 08:18:97 12:19
0
Fs (tsf)
500 0 15
-0.0
-5.0
-10.0
-15.0
-20.0
Max. Depth: 21.16 (ft)
Depth Inc.: 0.164 (ft)
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
IT
L
Sandy Silt
Silty Sand/Sand
Cemented Sand
Silt
Sandy Silt
Silty Sand/Sand
Sandy Silt
Silty Sand/Sand
Sandy Silt
Cemented Sand
Stiff Fine Grained
Cemented Sand
Stiff Fine Grained
Cemented Sand
SET: Soil Behavior Type (Robertson and Campanella 1988)
en
£3 en1
a0)o
31<a'c•^CD
03
EGG WOODWARD CLYDE Site : CARLSBAD SEUER S/D
Location : C —26
Engineer : S. PRICE
Date- : 08: 1 8: 97 1 1: 24
Qt (tsf)Fs (tsf)
0 500 15 0
U (psi) Rf (%) SBT
100 0.0 5.0 0 12
-0.0
-5.0
-10.0
-15.0
-20.0
IT Sensitive Fines
Silly Clay
Silly Sand/Sand
Cemenled Sand
Sill
Sandy Sill
Sill
Sandy Sill
Stiff Fine Grained
Sandy Sill
Silly Sand/Sand
Sandy Sill
Silly Sand/Sand
Cemented Sand
Stiff Fine Grained
Max. Depth: 17.55 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
en
en en a CD C3 CD .CD LTD CZ3
WOODWARD CLYDE Site : CARLSBAD SEUIER S/D
Location : C-28
Engineer : S. PRICE
Date : 08: 18: 97 10: 02
Qt (tsf)
0
Fs (tsf)
500 0 15
-0.0
-5.0
_c+->a
Q
-10.0
-15.0
-20.0
toc
Max. Depth: 17.22 (ft)
Depth Inc.: 0.164 (ft)
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
Silly Sand/Sand
Sand
Silty Sand/Sand
Sand
Cemented Sand
SBT: Soil Behavior Type (Robertson and Campanella 1988)
EGG WOODWARD CLYDE Site : CARLSBAD SEUER SxD Engineer : S. PRICE
Location :'c-29 Date : 08:19:97 06:22
Qt (tsf)
-0.0
-5.0
.c -10.0
a
IDa
-15.0
-20.0
(0
I'
CO*»to
Fs (tsf)
500 0 15
Handaugered
Max. Depth: 29.53 (ft)
Depth Inc.: 0.164 (ft)
Handahgered
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 lc
landnugfcred Handa igered
Silty Sand/Sand
Sandy Silt
Silty Sand/Sand
Sandy Silt
Sandy Sill
Silt
Sandy Silt
Silty Sand/Sand
Sand
Sandy Silt
Cemented Sand
SBT: Soil Behavior Type (Robertson and Campanella 1988)
a a a era a ca CD' a en
Q.QJQ
31<o'c
10o
EGG WOODWARD CLYDE Site ; CARLSBAD SEWER S/D
Location : C-29
Engineer : S. PRICE
Date : 08: 19: 97 06: 22
Qt (tsf)
500
Fs (tsf)
0 15
U (psi)
0 100
Rf (%) SBT
0.0 5.0 0 12
-22.4
-27.4
.c -32.4
-37.4
-42.4
Cemented Sand
Sandy SUt
Silty Sand/Sand
Cemented Sand
Stiff Fine Grained
Cemented Sand
Stiff Fine Grained
Cemented Sand
Max. Depth: 29.53 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
a era a a C3 CI3
EGG WOODWARD CLYDE Site : CARLSBAD SEUER S/D
Locat i on : C-31
Engineer : S. PRICE
Date : 08: 18: 97 16: 07
Qt (tsf)
500
-0.0
-5.0
-10.0
Q.03Q
Tl
(5'
00
Fs (tsf)
0 . 15
U (psi)
0 100
Rf (%) SBT
0.0 5.0 0
Sandy Silt
Silly Sand/Sand
Sandy Silt
Cemented Sand
Max. Depth: 30.84 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
C3 -cn CD tin -eo cn-a c=3 a j
EGG WOODWARD CLYDE Site : CARLSBAD. SEUIER S/D
Location : C-31
Engineer : S. PRICE
Date : 08:18:97 16:07
Qt (tsf)Fs (tsf)
500 0 15
-27.4
.c -32.4
a.01Q
-37.4
-42.4
31<Q'c
toNJ
Max. Depth: 30.84 (ft)
Depth Inc.: 0.164 (ft)
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
Cemented Sand
Sandy Silt
Cemented Sand
SBT: Soil Behavior Type (Robertson and Campanella 1988)
EGG WOODWARD CLYDE Site : CARLSBAD SEUER S/D
Location : C-32
Engineer : S. PRICE
Date : 08: 19: 97 08: 01
Qt (tsf)
0 500
Fs (tsf)
0 15
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
-0.0
-5.0
-10.0
Q.(DQ
-15.0
-20.0
COc
3
00
toCO
I I f
L
Sand
Silty Sand/Sand
Sandy Silt
Silt
Sensitive Fines
Silt
Sandy Silt
Silty Sand/Sand
Sand
Silty Sand/Sand
Sandy Silt
Silty Sand/Sand
Max. Depth: 34.12 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
CD
EGG WOODWARD CLYDE Site : CARLSBAD SEUIER S/D
Location : C-32
Engineer : S. PRICE
Date : O8: 19: 97 08: 01
Qt (tsf)
0 500
Fs (tsf)
0 15
-22.4
-27.4
-32.4
Q.mQ
-37.4
-42.4
IS
OJ
CO-b.
Max. Depth: 34.12 (ft)
Depth Inc.: 0.164 (ft)
U (psi) Rf (%) SBT
0 100 0.0 5.0 0 12
Silly Sand/Sand
SBT: Soil Behavior Type (Robertson and Campanella 1988)
C3
WOODWARD CLYDE Site : CARLSBAD SEUER S/D
Location : C-34
Engineer : S. PRICE
Date : 08: 19: 97 09: 31
Qt (tsf)Fs (tsf)
0 500 15
U (psi)
0 100
Rf (%).
0.0 5.0
-0.0
-5.0
-10.0
d0)Q
-15.0
-20.0
3co
§
COtn
i i
Cemented Sand
Stiff Fine Grained
Cemented Sand
Stiff Fine Grained
Max. Depth: 13.45 (ft)
Depth Inc.: 0.164 (ft)
SBT: Soil Behavior Type (Robertson and Campanella 1988)
C3 a €=3 e=3 CD co
aCDa
eac
DO
wo>
WOODWARD CLYDE Site : CARLSBAD SEUER S/D
Location : C-34B
Engineer : S. PRICE
Date : 08:21:97 18:01
Qt (tsf)
0 500
-0.0
-5.0
jc -10.0
-15.0 •
-20.0
Hands igerod
Max. Depth: 20.18 (ft)
Depth Inc.: 0.164 (ft)
U (psi)
0 100
Rf (%)
0.0 5.0
SBT
I I M I I I I I Sandy Silt
Silt
Sandy Sill
Silt
Sandy Silt
Silt
Silly Sand/Sand
Sandy Silt
Silt
Stiff Fine Grained
Silt
Sandy Silt
Cemented Sand
Sandy Silt
Silt
Silly Sand/Sand
Sandy Silt
Clayey Sill
Silly Clay
Clayey Sill
Sill
Cemenled Sand
SBT: Soil Behavior Type (Robertson and Carnpanella 1988)