HomeMy WebLinkAbout5035; LA COSTA WATER MAIN REPLACEMENT; GEOTECHNICAL EVALUATION; 2017-01-27
GEOTECHNICAL EVALUATION
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
PREPARED FOR:
City of Carlsbad
5950 El Camino Real
Carlsbad, California 92008
PREPARED BY:
Ninyo & Moore
Geotechnical and Environmental Sciences Consultants
5710 Ruffin Road
San Diego, California 92123
January 27, 2017
Project No. 108064001
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TABLE OF CONTENTS
Page
1. INTRODUCTION ....................................................................................................................1
2. SCOPE OF SERVICES ............................................................................................................1
3. SITE AND PROJECT DESCRIPTION ...................................................................................2
4. FIELD EXPLORATION AND LABORATORY TESTING ..................................................2
5. GEOLOGY AND SUBSURFACE CONDITIONS .................................................................3
5.1. Regional and Geologic Setting .....................................................................................3
5.2. Site Geology .................................................................................................................4
5.2.1. Fill .......................................................................................................................4
5.2.2. Young Alluvial Flood Plain Deposits .................................................................4
5.2.3. Old Alluvial Flood Plain Deposits ......................................................................5
5.2.4. Delmar Formation ...............................................................................................5
5.2.5. Santiago Formation .............................................................................................5
5.3. Groundwater .................................................................................................................5
6. GEOLOGIC HAZARDS ..........................................................................................................6
6.1. Faulting and Seismicity ................................................................................................6
6.1.1. Ground Surface Rupture .....................................................................................6
6.1.2. Strong Ground Motions ......................................................................................6
6.1.3. Liquefaction ........................................................................................................7
6.1.4. Dynamic Settlement of Saturated Soils...............................................................8
6.1.5. Lateral Spreading ................................................................................................8
6.2. Landsliding ...................................................................................................................9
7. CONCLUSIONS ......................................................................................................................9
8. RECOMMENDATIONS ........................................................................................................11
8.1. Earthwork ...................................................................................................................11
8.1.1. Site Preparation .................................................................................................11
8.1.2. Excavation Characteristics ................................................................................12
8.1.3. Temporary Excavations and Shoring ................................................................12
8.1.4. Excavation Bottom Stability .............................................................................14
8.1.5. Construction Dewatering ..................................................................................14
8.1.6. Pipe Bedding and Pipe Zone Backfill ...............................................................15
8.1.7. Trench Zone Backfill Materials ........................................................................15
8.1.8. Fill Placement and Compaction ........................................................................16
8.2. Modulus of Soil Reaction (E') ....................................................................................16
8.3. Trenchless Piping Installation .....................................................................................17
8.4. Lateral Pressures for Thrust Blocks and Jacking ........................................................17
8.5. Seismic Design Parameters .........................................................................................17
8.6. Pavement Reconstruction ...........................................................................................18
8.7. Corrosivity ..................................................................................................................18
8.8. Concrete Placement ....................................................................................................19
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8.9. Pre-Construction Conference ......................................................................................19
8.10. Plan Review and Construction Observation ...............................................................19
9. LIMITATIONS .......................................................................................................................20
10. REFERENCES .......................................................................................................................22
Table
Table 1 – 2016 California Building Code Seismic Design Criteria ...............................................18
Figures
Figure 1 – Site Location
Figure 2 – Boring Locations
Figure 3 – Fault Locations
Figure 4 – Geology
Figure 5 – Lateral Earth Pressures for Braced Excavation
Figure 6 – Thrust Block Lateral Earth Pressure Diagram
Appendices
Appendix A – Boring Logs
Appendix B – Laboratory Testing
Appendix C – Liquefaction Analyses
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1. INTRODUCTION
In accordance with your request and our proposal dated December 7, 2016, we have performed
a geotechnical evaluation for the proposed La Costa Golf Course Waterline Replacement pro-
ject located in Carlsbad, California (Figure 1). This report presents our findings and
conclusions regarding the geotechnical conditions along the subject alignment and our recom-
mendations for the design and construction of this project.
2. SCOPE OF SERVICES
Ninyo & Moore’s scope of services for this project included review of pertinent background da-
ta, performance of a geologic reconnaissance, subsurface exploration, and engineering analysis
with regard to the proposed project. Specifically, we performed the following tasks:
Reviewing background information including available topographic maps, geologic data, fault
maps, aerial photographs, and the project alignment plan.
Coordination and meeting with representatives of the City of Carlsbad and La Costa Golf
Course regarding the performance of our fieldwork.
Coordinating and mobilizing for a geotechnical reconnaissance to observe the existing site
conditions and to mark-out the boring locations for utility clearance by Underground Service
Alert (USA).
Obtaining boring permits from the County of San Diego Department of Environmental Health.
Performing a subsurface exploration program consisting of excavating, logging, and sampling of
two exploratory borings.
Performing geotechnical laboratory testing on representative soil samples to evaluate ge-
otechnical characteristics and design parameters.
Performing geotechnical analysis of the data obtained from our site reconnaissance, subsur-
face exploration, and laboratory testing.
Preparing this report presenting our findings, conclusions, and recommendations regarding
the geotechnical design and construction of the project.
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3. SITE AND PROJECT DESCRIPTION
The project is located at the La Costa Golf Course in Carlsbad, California (Figure 1). An existing
City of Carlsbad water main, consisting of 8-inch diameter asbestos cement pipe (ACP), extends
through the golf course property. This ACP water main is located in the eastern portion of the
golf course property and extends generally in the north-south direction for the majority of the
alignment (Figure 2). The existing features and improvements in the project area include San
Marcos Creek, vehicular pavements, dirt access roads, and paved golf cart paths. The vegetation
in the project area generally consists of landscaped trees and grass. Single- and multi-unit hous-
ing developments exist on the north and south of the project area.
We understand that the project will include the abandonment of the existing ACP water main
segment and the installation of approximately 970 linear feet of new 8-inch diameter pipeline.
Approximately 580 linear feet of the new alignment is anticipated to consist of high-density
polyethylene (HDPE) waterline piping and the remaining 390 linear feet is anticipated to con-
sist of polyvinyl chloride (PVC) waterline piping. The HDPE section of the piping is proposed
to be installed using trenchless methods such as horizontal directional drilling (HDD) to extend
beneath San Marcos Creek and portions of the golf course. The PVC section of the piping is
proposed to be installed using cut-and-cover methods. Based on the plans (City of Carlsbad,
2014), the trenchless portion of the piping installation will extend to depths of up to approxi-
mately 30 feet below the existing grade. Surface elevations along the pipeline alignment range
from a low of approximately 8 feet above mean sea level (MSL) near San Marcos Creek to a
high of approximately 60 feet above MSL at the south end of the alignment. The pipe invert ele-
vations are anticipated to vary from a low of approximately -10 feet MSL near the San Marcos
Creek to a high of approximately 54 feet MSL at the south end of the alignment.
4. FIELD EXPLORATION AND LABORATORY TESTING
Our subsurface exploration was conducted on December 12 and 13, 2016 and consisted of drill-
ing, logging, and sampling of two small-diameter exploratory borings (B-1 and B-2). The borings
were drilled to depths up to approximately 51½ feet using a truck-mounted drill rig equipped with
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8-inch diameter, hollow-stem augers. During the drilling operations, the borings were logged and
sampled by an engineering geologist from Ninyo & Moore. Representative bulk and in-place soil
samples were obtained from within the borings. The samples were then transported to our in-house
geotechnical laboratory for testing. The approximate locations of the exploratory borings are shown
on Figure 2. The boring locations were planned based on our discussions with the City and
La Costa Golf Course representatives. As depicted on Figure 2, the borings were performed with-
in the vicinity of the entry and receiving pits. Logs of the borings are included in Appendix A.
The geotechnical laboratory testing that was performed on representative soil samples included
an evaluation of in-situ dry density and moisture content, gradation (sieve) analysis, Atterberg
limits, shear strength, expansion index, and soil corrosivity. The results of the in-situ dry density
and moisture content tests are presented on the boring logs in Appendix A. The results of the oth-
er laboratory tests are presented in Appendix B.
5. GEOLOGY AND SUBSURFACE CONDITIONS
Our findings regarding regional and site geology along with groundwater conditions in the pro-
ject area are provided in the following sections.
5.1. Regional and Geologic Setting
The project area is situated in the coastal foothill section of the Peninsular Ranges Geo-
morphic Province. This geomorphic province encompasses an area that extends
approximately 900 miles from the Transverse Ranges and the Los Angeles Basin south to
the southern tip of Baja California (Harden, 2004; Norris and Webb, 1990). The province
varies in width from approximately 30 to 100 miles. In general, the province consists of rug-
ged mountains underlain by Jurassic metavolcanic and metasedimentary rocks, and
Cretaceous igneous rocks of the Southern California Batholith. The portion of the province
in San Diego County that includes the project area consists generally of Quaternary and Ter-
tiary age sedimentary rock.
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The Peninsular Ranges Province is traversed by a group of sub-parallel faults and fault
zones trending roughly northwest. Several of these faults, which are shown on Figure 3, are
considered active faults. The Elsinore, San Jacinto, and San Andreas faults are active fault
systems located northeast of the project area and the Rose Canyon, Coronado Bank, San Di-
ego Trough, and San Clemente faults are active faults located west of the project area. The
Rose Canyon Fault Zone, the nearest active fault system, has been mapped approximately
6 miles west of the project area. Major tectonic activity associated with these faults within
this regional tectonic framework consists primarily of right-lateral, strike-slip movement.
5.2. Site Geology
Geologic units encountered during our background review, reconnaissance, and subsur-
face exploration included fill, young alluvial flood plain deposits, old alluvial flood plain
deposits, and materials of the Delmar Formation (Kennedy and Tan, 2007). Generalized
descriptions of the earth units encountered are provided in the subsequent sections. Addi-
tional descriptions of the subsurface units are provided on the boring logs in
Appendix A. A geologic map of the region is presented on Figure 4.
5.2.1. Fill
Fill was encountered in each of our exploratory borings from the ground surface and ex-
tending to depths up to approximately 5½ feet. As encountered, the fill generally
consisted of various shades of brown, moist, medium dense, silty and clayey sand.
Gravel and cobbles were encountered within the fill materials.
5.2.2. Young Alluvial Flood Plain Deposits
Holocene to Quaternary-age young alluvial flood plain deposits, or young alluvium, were
encountered in our exploratory borings underlying the fill materials and extending to
depths up to approximately 38 feet. As encountered, the young alluvium generally con-
sisted of various shades of gray, brown, and olive, moist to wet, soft to hard sandy clay
and loose to medium dense, clayey sand. Difficult drilling conditions were encountered in
boring B-1 in a gravel and cobble bed at a depth of approximately 29 to 33 feet.
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5.2.3. Old Alluvial Flood Plain Deposits
Quaternary-age old alluvial flood plain deposits, or old alluvium, were encountered in ex-
ploratory borings underlying the young alluvium and extending to a depth of approximately
40 feet in boring B-1 and to the total depth explored of approximately 51½ feet in boring
B-2. As encountered, the old alluvium generally consisted of various shades of gray and
brown, wet, medium dense to very dense, silty and clayey sand.
5.2.4. Delmar Formation
Materials of the Tertiary-age Delmar Formation were encountered in exploratory boring
B-1 underlying the old alluvium and extending to the total depth explored of approxi-
mately 51½ feet. As encountered, the materials of the Delmar Formation generally
consisted of light gray and dark gray, wet, moderately to strongly cemented, silty sand-
stone and strongly indurated sandy claystone.
5.2.5. Santiago Formation
Although not encountered in our borings, materials of the Tertiary-age Santiago For-
mation have been mapped near the site. Stratigraphically, the Santiago Formation
underlies and is partially interbedded with the Delmar Formation. The materials of the
Santiago Formation generally consist of weakly to strongly indurated claystone and silt-
stone, and weakly to strongly cemented sandstone. The Santiago Formation may contain
strongly cemented/concretionary layers (Kennedy and Tan, 2005).
5.3. Groundwater
Groundwater was encountered during our subsurface exploration at depths of approximately 10 feet
in Boring B-1 and approximately 18 feet in Boring B-2. Groundwater was measured in a nearby mon-
itoring well at a depth of approximately 6 feet (Geotracker, 2017). Due to the site topography, the
proximity to the San Marcos Creek, nearby areas of landscaping, and the potential presence for exist-
ing utility trench lines, zones of seepage and/or perched water should be anticipated. Fluctuations in
the groundwater level and perched water conditions may occur due to variations in ground surface to-
pography, subsurface geologic conditions and structure, rainfall, irrigation, and other factors.
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6. GEOLOGIC HAZARDS
In general, hazards associated with seismic activity include ground surface rupture, strong ground
motion, liquefaction, and landslides. These considerations are discussed in the following sections.
6.1. Faulting and Seismicity
Like most of Southern California, the project area is considered to be seismically active.
Based on our review of the referenced geologic maps and stereoscopic aerial photographs,
as well as our geologic field reconnaissance, the project alignment is not underlain by
known active or potentially active faults (i.e., faults that exhibit evidence of ground dis-
placement in the last 11,000 years and 2,000,000 years, respectively). Major known active
faults in the region consist generally of en-echelon, northwest-striking, right-lateral, strike-
slip faults. These include the Rose Canyon, Coronado Bank, San Diego Trough, and San
Clemente faults, located to the west of the site, and the Elsinore, San Jacinto and San Andre-
as faults, located to the east of the site. The locations of these faults are shown on Figure 3.
The closest known active fault is the Rose Canyon Fault, which can generate an earthquake
maximum moment magnitude Mmax of up to 6.9 according to literature published by the
USGS (2008). It is located approximately 6 miles west of the project area.
6.1.1. Ground Surface Rupture
Based on our review of the referenced literature and our site reconnaissance, no active
faults are known to cross the project alignment. Therefore, the potential for ground rup-
ture due to faulting at the site is unlikely. However, lurching or cracking of the ground
surface as a result of nearby seismic events is possible.
6.1.2. Strong Ground Motions
The 2016 California Building Code (CBC) specifies that the Risk-Targeted, Maximum
Considered Earthquake (MCER) ground motion response accelerations be used to eval-
uate seismic loads for design of buildings and other structures. The MCER ground
motion response accelerations are based on the spectral response accelerations for
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5 percent damping in the direction of maximum horizontal response and incorporate a
target risk for structural collapse equivalent to 1 percent in 50 years with deterministic
limits for near-source effects. The horizontal peak ground acceleration (PGA) that cor-
responds to the MCER for the project alignment was calculated as 0.45g using the
United States Geological Survey (USGS, 2016) seismic design tool (web-based).
The 2016 CBC specifies that the potential for liquefaction and soil strength loss be
evaluated, where applicable, for the Maximum Considered Earthquake Geometric Mean
(MCEG) peak ground acceleration with adjustment for site class effects in accordance
with the American Society of Civil Engineers (ASCE) 7-10 Standard. The MCEG peak
ground acceleration is based on the geometric mean peak ground acceleration with a
2 percent probability of exceedance in 50 years. The MCEG peak ground acceleration
with adjustment for site class effects (PGAM) was calculated as 0.41g using the USGS
(USGS, 2016) seismic design tool that yielded a mapped MCEG peak ground accelera-
tion of 0.45g for the site and a site coefficient (FPGA) of 1.092 for Site Class D.
6.1.3. Liquefaction
Liquefaction is the phenomenon in which loosely deposited granular soils with silt and
clay contents of less than approximately 35 percent and non-plastic silts located below
the water table undergo rapid loss of shear strength when subjected to strong earth-
quake-induced ground shaking. Ground shaking of sufficient duration results in the loss
of grain-to-grain contact due to a rapid rise in pore water pressure, and causes the soil to
behave as a fluid for a short period of time. Liquefaction is known generally to occur in
saturated or near-saturated cohesionless soils at depths shallower than 50 feet below the
ground surface. Factors known to influence liquefaction potential include composition
and thickness of soil layers, grain size, relative density, groundwater level, degree of
saturation, and both intensity and duration of ground shaking.
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The liquefaction potential of subsurface soils at the project site was evaluated using the
computer program LiquefyPro (CivilTech Software, 2007a) based on our boring data. A
design groundwater table depth of 5 feet below the existing ground surface was used in
our liquefaction evaluation. A moment magnitude of 6.9 associated with the Rose Canyon
Fault and the (MCEG) peak ground acceleration with adjustment for site class effects of
0.45g was used in our liquefaction analysis in accordance with 2016 CBC and ASCE 7-10
Standard. The liquefaction analyses results are presented in Appendix D. Our liquefaction
analysis indicates that loose to medium dense granular soils occurring below the design
groundwater level of 5 feet and up to a depth of 45 feet below the surface are generally
susceptible to liquefaction during the design seismic event.
6.1.4. Dynamic Settlement of Saturated Soils
As a result of liquefaction, the proposed improvements may be subject to several haz-
ards, including liquefaction-induced settlement. In order to estimate the amount of post-
earthquake settlement (dynamic settlement), the method proposed by Ishihara and Yo-
shimine (1992) was chosen for the evaluation. The amount of soil settlement during a
strong seismic event depends on the thickness of the liquefiable layers and the density
and/or consistency of the soils.
Under the current conditions, post-earthquake total settlement of up to approximately
3 inches was calculated for the project site. Assuming relatively continuous subsurface
stratigraphy across the site, we estimate differential settlement on the order of 1½ inches
over a horizontal distance of 40 feet.
6.1.5. Lateral Spreading
Lateral spreading of ground surface during an earthquake usually takes place along weak
shear zones that have formed within a liquefiable soil layer. Lateral spread has generally
been observed to take place in the direction of a free-face but has also been observed to a
lesser extent on ground surfaces with very gentle slopes. An empirical model developed
by Youd and Bartlett (2002) is typically used to predict the amount of horizontal ground
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displacement within a site. For a site located in proximity to a free-face, the amount of
lateral ground displacement is strongly correlated with the distance of the site from the
free-face. Other factors such as earthquake magnitude, distance from the earthquake epi-
center, thickness of the liquefiable layers, and the fines content and particle sizes of the
liquefiable layers also affect the amount of lateral ground displacement.
The bottom of San Marcos Creek is at an approximate elevation of 8 feet MSL in the
project area. The pipeline will be installed at a considerable depth below the bottom of
the San Marcos Creek, where the creek crosses the proposed project alignment. Addi-
tionally, based on our boring data, the soils below the design groundwater depth of
5 feet up to the bottom of the creek depth consist of predominantly fine grained soils
(i.e., CL). Therefore, the potential for lateral spreading to occur at the project site is
considered low and not anticipated to be a design consideration for the pipeline.
6.2. Landsliding
No landslides or indications of deep-seated landslides were noted underlying the project site
during our field exploration or our review of available geologic literature and topographic
maps. Our review of Landslide Hazard Maps (Tan, 1995) indicates that the alignment is sit-
uated in Landslide Susceptibility Area 2, which represents areas that are marginally
susceptible to landsliding.
7. CONCLUSIONS
Based on our review of the referenced background data and the results of our subsurface explora-
tion, it is our opinion that construction of the proposed project is feasible from a geotechnical
standpoint provided that the recommendations of this report are incorporated into the design of the
project. Geotechnical considerations include the following:
Based on the results of our background review and subsurface exploration, the geologic
units that underlie the project alignment include fill, young alluvium, old alluvium, and ma-
terials of the Delmar Formation and Santiago Formation.
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Onsite soils encountered in our borings consist of predominately clayey materials. Soils classi-
fied as clay (CL or CH) are not considered suitable for reuse as trench or structural backfill.
Granular materials derived from on-site excavations are generally considered suitable for re-
use as backfill, provided they meet the recommendations for backfill materials presented in the
following sections.
Groundwater was encountered during our subsurface exploration at depths of approximately
10 feet in Boring B-1 and approximately 18 feet in Boring B-2. Groundwater was measured
in a nearby monitoring well at a depth of approximately 6 feet (Geotracker, 2017). Fluctu-
ations in the groundwater level and perched water conditions or seepage should be expected.
Accordingly, the contractor should be prepared to address issues associated with shallow
groundwater conditions such as excavation stability, dewatering, wet soils, and caving.
The on-site fill, young alluvium, and old alluvium should be generally excavatable with
conventional heavy-duty earth moving construction equipment in generally good condition
to the anticipated construction depths. Due to the loose to medium dense nature and wet condi-
tions in the fill and alluvial materials, the contractor should anticipate encountering caving
and/or sloughing conditions when excavating these materials. Difficult drilling conditions were
encountered in boring B-1 in a gravel and cobble bed at a depth of approximately 29 to
33 feet. Gravel and cobbles should also be anticipated at varying depths along the project
alignment. Accordingly, the contractor should be prepared to use specialized equipment to
mitigate difficulty in performing excavations and caving of gravel and cobbles.
Both soft and hard drilling and excavation conditions should be expected along the project
alignment.
The Delmar Formation encountered in boring B-1 was moderately to strongly cemented and
strongly indurated. Caliche was also encountered in Delmar Formation. Accordingly, the
contractor should be prepared to use specialized equipment and techniques, including heavy
ripping, rock breaking, or coring, for the excavations extending into formational materials.
Trench excavations that encounter wet soils or that are close to or below the water table may
be unstable for the support of heavy equipment. The contractor should anticipate yielding and
unstable excavation bottom conditions. Recommendations for stabilizing the yielding and un-
stable excavation bottoms are provided in the following sections.
No active faults are mapped underlying the project alignment. The active Rose Canyon fault
has been mapped approximately 6 miles west of the project alignment.
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There is a potential for liquefaction at the project site. Post-earthquake total settlement of up
to approximately 3 inches was calculated for the project site. Assuming relatively continuous
subsurface stratigraphy across the site, we estimate differential settlement on the order of
1½ inches over a horizontal distance of 40 feet.
Based on the results of our soil corrosivity tests, the soils along the project alignment are
considered corrosive as compared to ACI 318 and Caltrans corrosion criteria (2015).
8. RECOMMENDATIONS
Based on our understanding of the project, the following recommendations are provided for the
design and construction of the project. The proposed site improvements should be constructed in
accordance with this report and the requirements of the applicable governing agencies.
8.1. Earthwork
In general, earthwork should be performed in accordance with the recommendations pre-
sented in this report. Ninyo & Moore should be contacted for questions regarding the
recommendations or guidelines presented herein.
8.1.1. Site Preparation
Prior to performing site excavations, the site should be cleared of vegetation, surface
obstructions, rubble and debris, abandoned utilities and foundations, and other deleteri-
ous materials. Existing utilities within the project limits, if any, should be re-routed or
protected from damage by construction activities. Obstructions that extend below finish
grade, if any, should be removed and the resulting holes filled with compacted soils.
Materials generated from the clearing operations should be removed from the project
site and disposed of at a legal dumpsite.
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8.1.2. Excavation Characteristics
Our evaluation of the excavation characteristics of the on-site materials is based on the
results of our exploratory borings, our site observations, and our experience with similar
materials. In our opinion, on-site fill, young alluvium, and old alluvium should be gen-
erally excavatable with conventional heavy-duty earth moving construction equipment
in generally good condition to the anticipated construction depths. Due to the loose to
medium dense nature and wet conditions in the fill and alluvial materials, the contractor
should anticipate encountering caving and/or sloughing conditions when excavating these
materials. Difficult drilling conditions were encountered in boring B-1 in a gravel and
cobble bed at a depth of approximately 29 to 33 feet. Gravel and cobbles should also be
anticipated at varying depths along the project alignment. Accordingly, the contractor
should be prepared to use specialized equipment to mitigate difficulty in performing ex-
cavations and caving of gravel and cobbles. Both soft and hard drilling and excavation
conditions should be expected along the project alignment. The Delmar Formation en-
countered in our boring was moderately to strongly cemented and strongly indurated.
Caliche was also encountered in Delmar Formation. Accordingly, the contractor should
be prepared to use specialized equipment and techniques, including heavy ripping, rock
breaking, or coring, for the excavations extending into formational materials.
8.1.3. Temporary Excavations and Shoring
For temporary excavations, we recommend that the following Occupational Safety and
Health Administration (OSHA) soil classifications be used:
Fill, Young Alluvium, and Old Alluvium Type C
Delmar Formation Type B
Upon making the excavations, the soil classifications and excavation performance
should be evaluated in the field by the geotechnical consultant in accordance with the
OSHA regulations Temporary excavations should be constructed in accordance with
OSHA recommendations. For trenches or other excavations, OSHA requirements re-
garding personnel safety should be met using appropriate shoring (including trench
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boxes) or by laying back the slopes to no steeper than 1.5:1 (horizontal to vertical) in
fill and young alluvium and 1:1 in old alluvium and materials of the Delmar Formation.
Temporary excavations that encounter seepage may be shored or stabilized by placing
sandbags or gravel along the base of the seepage zone. Excavations encountering seep-
age should be evaluated on a case-by-case basis. On-site safety of personnel is the
responsibility of the contractor.
In areas with limited space for construction where temporary excavations may not be laid
back at the recommended slope inclination and at the jacking and receiving pits, a shoring
system with bracing may be incorporated to stabilize the excavation sidewalls during con-
struction. The shoring system should be designed using the magnitude and distribution of
lateral earth pressures presented on Figure 5. The recommended design earth pressures are
based on the assumptions that (a) the shoring system is constructed without raising the
ground surface elevation behind the shoring, (b) that there are no surcharge loads, such as
soil stockpiles, construction materials, construction equipment, or vehicular traffic, and
(c) that no loads act above a 1:1 plane extending up and back from the base of the shoring
system. For shoring subjected to the above-mentioned surcharge loads, the contractor
should include the effect of these loads on lateral earth pressures acting on the shoring wall.
Settlement of the ground surface may occur behind the shoring wall during excavation.
The amount of settlement depends on the type of shoring system, the quality of contrac-
tor’s workmanship, and soil conditions. Settlement may cause distress to adjacent
structures, if present. To reduce the potential for distress to adjacent structures, we rec-
ommend that the shoring system be designed to limit the ground settlement behind the
shoring to ½ inch or less. Possible causes of settlement that should be addressed include
vibration during installation of the sheet piling, excavation for construction, construction
vibrations, dewatering, and removal of the support system. We recommend that the poten-
tial settlement distress be evaluated carefully by the contractor prior to construction.
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The contractor should retain a qualified and experienced engineer to design the shoring sys-
tem. The shoring parameters presented in this report are for preliminary design purposes
and the contractor should evaluate the adequacy of these parameters and make appropriate
modifications for their design. We recommend that the contractor take appropriate measures
to protect workers. OSHA requirements pertaining to worker safety should be observed. We
further recommend that the construction methods provided herein be carefully evaluated by
a qualified specialty contractor prior to commencement of the construction.
8.1.4. Excavation Bottom Stability
Excavation bottoms that expose existing fill or alluvium near or below groundwater may
encounter wet and/or unstable bottom conditions. Unstable excavation bottom conditions
may be mitigated by overexcavating the excavation bottom to suitable depths and placing
a layer of compacted ¾- to 1½-inch crushed gravel encased in a woven geotextile
(e.g., Mirafi® 600X geotextile or an approved equivalent). Recommendations for stabiliz-
ing excavation bottoms should be based on evaluation in the field by the geotechnical
consultant at the time of construction.
8.1.5. Construction Dewatering
As noted, groundwater was encountered in the exploratory borings and will impact pro-
posed construction. In addition, fluctuations in the groundwater levels may also occur
between the time of our borings and construction. Dewatering measures during excava-
tion operations should be planned by the contractor’s engineer and reviewed by the
design engineer. Considerations for construction dewatering should include geotech-
nical characteristics, fluctuations in groundwater depth, anticipated drawdown, volume
of pumping, potential for settlement, and groundwater discharge. Disposal of ground-
water should be permitted in accordance with guidelines of the Regional Water Quality
Control Board (RWQCB).
La Costa Water Main Replacement January 27, 2017
Carlsbad, California Project No. 108064001
108064001 R.doc 15
8.1.6. Pipe Bedding and Pipe Zone Backfill
We recommend that pipes be supported on 6 inches or more of granular bedding materi-
al. Pipe bedding and pipe zone backfill typically consists of graded aggregate with a
coefficient of uniformity of three or more. Pipe bedding and pipe zone backfill should be
sand that has a Sand Equivalent (SE) of 30 or more with no material larger than ½-inch
(City of Carlsbad, 2016a). These materials should be placed below, around the sides,
and on top of the pipe. In addition, the pipe zone backfill should extend 1 foot or more
above the top of the pipe (City of Carlsbad, 2016b). We do not recommend the use of
crushed rock as bedding material. It has been our experience that the voids within a crushed
rock material are sufficiently large to allow fines to migrate into the voids, thereby creating
the potential for sinkholes and depressions to develop at the ground surface.
Special care should be taken not to allow voids beneath and around the pipe. Compac-
tion of the bedding material and backfill should proceed up both sides of the pipe.
Backfill, including bedding materials, should be placed in accordance with the recom-
mendations presented in the following sections.
8.1.7. Trench Zone Backfill Materials
Onsite soils classified as clay (CL or CH) or silt (ML or MH) are not considered suitable
for reuse as trench backfill. In general, on-site soils granular soils with an organic con-
tent of less than approximately 3 percent by volume (or 1 percent by weight) that meet
the following gradations are considered suitable for reuse as trench zone backfill. For
the purpose of this report, the trench zone is considered to extend from 1 foot above the
top of the pipe to the top of the trench. The backfill material should not generally con-
tain rocks or lumps larger than approximately 3 inches, and not more than
approximately 30 percent particles larger than ¾ inch. Larger chunks, if generated dur-
ing excavation, may be broken into acceptably sized pieces or disposed of offsite.
Imported fill material should be generally granular soils and have a low expansion po-
tential (expansion index of 50 or less) as evaluated by ASTM International (ASTM)
Test Method D 4829. Import material should also have low corrosion potential (chloride
La Costa Water Main Replacement January 27, 2017
Carlsbad, California Project No. 108064001
108064001 R.doc 16
content less than 500 parts per million [ppm], soluble sulfate content of less than
0.1 percent, pH of 5.5 or more, and an electrical resistivity of more than 1,000 ohm-cm).
Materials for use as backfill should be evaluated by Ninyo & Moore’s representative
prior to filling or importing.
8.1.8. Fill Placement and Compaction
Fill and trench backfill should be compacted by mechanical methods in horizontal lifts
to a relative compaction of 90 percent as evaluated by the latest edition of
ASTM D 1557. The upper 12 inches of street subgrade and aggregate base materials
beneath pavement areas should be compacted to a relative compaction of 95 percent.
Fill and trench backfill soils should be placed at the laboratory optimum moisture con-
tent as evaluated by the latest edition of ASTM D 1557. The optimum lift thickness of
fill will depend on the type of compaction equipment used, but generally should not ex-
ceed 8 inches in loose thickness. Successive lifts should be treated in a like manner until
the desired finished grades are achieved. Special care should be taken to avoid pipe
damage when compacting trench backfill above the pipe.
8.2. Modulus of Soil Reaction (E')
The modulus of soil reaction (E') is used to characterize the stiffness of soil backfill placed
at the sides of buried flexible pipes for the purpose of evaluating deflection caused by the
weight of the backfill over the pipe (Hartley and Duncan, 1987). A soil reaction modulus of
1,000 pounds per square inch (psi) may be used for an excavation depth of up to about 5 feet
when backfilled with granular soil compacted to a relative compaction of 90 percent as
evaluated by the ASTM International (ASTM) D 1557. A soil reaction modulus of 1,500 psi
may be used for trenches deeper than 5 feet.
La Costa Water Main Replacement January 27, 2017
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108064001 R.doc 17
8.3. Trenchless Piping Installation
As noted, approximately 580 linear feet of the new HDPE pipeline alignment is proposed
to be installed using trenchless methods such as horizontal directional drilling to cross be-
neath San Marcos Creek and various portions of the golf course.
The contractor should anticipate a varying degree of drilling difficulty and conditions along
the alignment as discussed in the excavation characteristics section of this report. Addition-
ally, minor ground surface settlements may occur from the installation operations. The
contractor should provide means to reduce the surficial settlement and the effects on sur-
face improvements and adjacent underground utilities. The contractor should take
appropriate measures to reduce the loss of material at the drilling or casing head. Pipe fric-
tion can be reduced by overdrilling, excavating a slightly larger diameter than the pipe size,
and by using drilling mud or other lubricants. We recommend that an experienced specialty
contractor be used for the trenchless piping installation operations.
8.4. Lateral Pressures for Thrust Blocks and Jacking
Thrust restraint for buried pipelines and lateral pressures for jacking may be achieved by trans-
ferring the thrust force to the soil outside the pipe through a thrust block. Thrust blocks may be
designed using the lateral passive earth pressures presented on Figure 6. Thrust blocks should be
backfilled with granular backfill material, compacted as outlined in this report.
8.5. Seismic Design Parameters
Design of the proposed improvements should be performed in accordance with the require-
ments of governing jurisdictions and applicable building codes. Table 1 presents the seismic
design parameters for the site in accordance with the CBC (2016) guidelines and adjusted
MCER spectral response acceleration parameters (USGS, 2016).
La Costa Water Main Replacement January 27, 2017
Carlsbad, California Project No. 108064001
108064001 R.doc 18
Table 1 – 2016 California Building Code Seismic Design Criteria
Site Coefficients and Spectral Response Acceleration Parameters Values
Site Class D
Site Coefficient, Fa 1.080
Site Coefficient, Fv 1.594
Mapped Spectral Response Acceleration at 0.2-second Period, Ss 1.050 g
Mapped Spectral Response Acceleration at 1.0-second Period, S1 0.406 g
Spectral Response Acceleration at 0.2-second Period Adjusted for Site Class, SMS 1.134 g
Spectral Response Acceleration at 1.0-second Period Adjusted for Site Class, SM1 0.647 g
Design Spectral Response Acceleration at 0.2-second Period, SDS 0.756 g
Design Spectral Response Acceleration at 1.0-second Period, SD1 0.431 g
8.6. Pavement Reconstruction
Trench excavations in existing pavement areas may involve replacement of pavements as
part of the work. In general, trench pavement repair should include asphalt concrete (AC)
that is 1 inch thicker than the existing AC pavement section, and is 4 inches or more in
thickness, whichever is thicker. Also the AC and aggregate base materials should conform to
the material thicknesses and compaction requirements of the existing pavement section.
Subgrade and aggregate base materials should be compacted to 95 percent relative compac-
tion as evaluated by ASTM D 1557. AC should be compacted to 95 percent relative
compaction as evaluated by ASTM D1561 (Hveem density). Actual pavement reconstruction
should conform to the requirements of the city/agency of jurisdiction.
8.7. Corrosivity
Laboratory testing was performed on representative samples of near-surface soils to evaluate
soil pH, electrical resistivity, water-soluble chloride content, and water-soluble sulfate con-
tent. The soil pH and electrical resistivity tests were performed in general accordance with
California Test (CT) 643. Chloride content tests were performed in general accordance with
CT 422. Sulfate testing was performed in general accordance with CT 417. The laboratory
test results are presented in Appendix B.
La Costa Water Main Replacement January 27, 2017
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108064001 R.doc 19
The results of the corrosivity testing indicated electrical resistivities of 450 and 610 ohm-cm, soil
pH values of 6.7 and 7.5, chloride contents of 290 and 340 parts per million (ppm), and sulfate
contents of 0.056 and 0.092 percent (i.e., 560 and 920 ppm). Based on the laboratory test results,
as compared to ACI 318 and Caltrans (2015) corrosion criteria, the soils along the project
alignments would be classified as corrosive, which is defined as having earth materials with
an electrical resistivity of less than 1,000 ohm-centimeters, more than 500 ppm chlorides,
more than 0.10 percent sulfates (i.e., 1,000 ppm), and/or a pH of 5.5 or less.
8.8. Concrete Placement
Concrete in contact with soil or water that contains high concentrations of soluble sulfates can
be subject to chemical deterioration. As noted, laboratory testing indicated sulfate contents of
0.056 and 0.092 percent (i.e., 560 and 920 ppm), which is considered to represent a negligible
potential for sulfate attack (ACI, 318). However, due to the potential for variability of soils,
the proximity of the pipeline alignment to the San Marcos Creek, and the potential use of re-
cycled water, we recommend using Type V cement for concrete structures in contact with soil.
Concrete used on the project should have a water-cement ratio no higher than 0.45 by weight for
normal weight aggregate concrete.
8.9. Pre-Construction Conference
We recommend that a pre-construction meeting be held prior to commencement of construc-
tion. The owner or his representative, the agency representatives, the civil engineer, Ninyo &
Moore, and the contractor should be in attendance to discuss the plans, the project, and the
proposed construction schedule.
8.10. Plan Review and Construction Observation
The conclusions and recommendations presented in this report are based on analysis of ob-
served conditions in widely spaced exploratory borings. If conditions are found to vary from
those described in this report, Ninyo & Moore should be notified, and additional recommen-
dations will be provided upon request. Ninyo & Moore should review the project drawings
La Costa Water Main Replacement January 27, 2017
Carlsbad, California Project No. 108064001
108064001 R.doc 20
and specifications prior to the commencement of construction. Ninyo & Moore should per-
form the needed observation and testing services during construction operations.
The recommendations provided in this report are based on the assumption that Ninyo &
Moore will provide geotechnical observation and testing services during construction. In the
event that it is decided not to utilize the services of Ninyo & Moore during construction, we
request that the selected consultant provide the client with a letter (with a copy to Ninyo &
Moore) indicating that they fully understand Ninyo & Moore’s recommendations, and that
they are in full agreement with the design parameters and recommendations contained in this
report. Construction of proposed improvements should be performed by qualified subcon-
tractors utilizing appropriate techniques and construction materials.
9. LIMITATIONS
The field evaluation, laboratory testing, and geotechnical analyses presented in this geotechnical
report have been conducted in general accordance with current practice and the standard of care
exercised by geotechnical consultants performing similar tasks in the project area. No warranty,
expressed or implied, is made regarding the conclusions, recommendations, and opinions pre-
sented in this report. There is no evaluation detailed enough to reveal every subsurface condition.
Variations may exist and conditions not observed or described in this report may be encountered
during construction. Uncertainties relative to subsurface conditions can be reduced through addi-
tional subsurface exploration. Additional subsurface evaluation will be performed upon request.
Please also note that our evaluation was limited to assessment of the geotechnical aspects of the
project, and did not include evaluation of structural issues, environmental concerns, or the pres-
ence of hazardous materials.
This document is intended to be used only in its entirety No portion of the document, by itself, is
designed to completely represent any aspect of the project described herein. Ninyo & Moore
should be contacted if the reader requires additional information or has questions regarding the
content, interpretations presented, or completeness of this document.
La Costa Water Main Replacement January 27, 2017
Carlsbad, California Project No. 108064001
108064001 R.doc 21
This report is intended for design purposes only. It does not provide sufficient data to prepare an
accurate bid by contractors. It is suggested that the bidders and their geotechnical consultant per-
form an independent evaluation of the subsurface conditions in the project areas. The independent
evaluations may include, but not be limited to, review of other geotechnical reports prepared for
the adjacent areas, site reconnaissance, and additional exploration and laboratory testing.
Our conclusions, recommendations, and opinions are based on an analysis of the observed site
conditions. If geotechnical conditions different from those described in this report are encountered,
our office should be notified and additional recommendations, if warranted, will be provided upon
request. It should be understood that the conditions of a site could change with time as a result of
natural processes or the activities of man at the subject site or nearby sites. In addition, changes to
the applicable laws, regulations codes, and standards of practice may occur due to government ac-
tion or the broadening of knowledge. The findings of this report may, therefore, be invalidated over
time, in part or in whole, by changes over which Ninyo & Moore has no control.
This report is intended exclusively for use by the client. Any use or reuse of the findings, conclu-
sions, and/or recommendations of this report by parties other than the client is undertaken at said
parties’ sole risk.
La Costa Water Main Replacement January 27, 2017
Carlsbad, California Project No. 108064001
108064001 R.doc 22
10. REFERENCES
American Concrete Institute, 2011, ACI 318 Building Code Requirements for Structural Con-
crete (ACI 318) and Commentary (ACI 318R).
American Society of Civil Engineers (ASCE), 2010, Minimum Design Loads for Buildings and
Other Structures, ASCE 7-10.
California Building Standards Commission (CBSC), 2016, California Building Code (CBC), Ti-
tle 24, Part 2, Volumes 1 and 2.
California Department of Transportation (Caltrans), 2015, Corrosion Guidelines, Version 2.1,
Division of Engineering Services, Materials Engineering and Testing Services, Corrosion
and Structural Concrete, Field Investigation Branch: dated January.
Cao, T., Bryant, W. A., Rowshandel, B., Branum, D., and Willis, C. J., 2003, The Revised 2002
California Probabilistic Seismic Hazards Maps: California Geological Survey: dated June.
City of Carlsbad, 2014, Construction Plans for the La Costa Water Main Replacement, Project No.
39041 & 50351, Carlsbad Municipal Water District, Carlsbad, California: dated June.
City of Carlsbad, 2016a, Engineering Standards, Volume 2, Potable and Recycled Water Standards.
City of Carlsbad, 2016b, Engineering Standards, Volume 3, Standard Drawings and Specifications.
Geotracker, 2017, http://geotracker.swrcb.ca.gov/: accessed in January.
Google, Inc., 2016, www.googleearth.com: accessed in December.
Harden, D.R., 2004, California Geology, 2nd Edition: Prentice Hall, Inc.
Hartley, J.D., and Duncan, J.M., 1987, E’ and Its Variation with Depth: American Society of Civil
Engineers (ASCE), Journal of Transportation Engineering, Vol. 113, No. 5: dated September.
Jennings, C.W., 2010, Fault Activity Map of California and Adjacent Areas: California Geologi-
cal Survey, California Geologic Data Map Series, Map No. 6, Scale 1:750,000.
Kennedy, M.P., and Tan, S.S., 2007, Geologic Map of the Oceanside 30’ x 60’ Quadrangle, Califor-
nia, Scale 1:100,000.
Ninyo & Moore, In-House Proprietary Data.
Ninyo & Moore, 2016, Proposal for Additional Services - Geotechnical Evaluation, La Costa
Golf Course Waterline Replacement, Carlsbad, California, Proposal No P-21459: dated
December 7.
Norris, R. M. and Webb, R. W., 1990, Geology of California, Second Edition: John Wiley & Sons, Inc.
Public Works Standards, Inc., 2015, “Greenbook,” Standard Specifications for Public Works Con-
struction.
La Costa Water Main Replacement January 27, 2017
Carlsbad, California Project No. 108064001
108064001 R.doc 23
Tan, S.S., 1995, Landslide Hazards in the Northern Part of the San Diego Metropolitan Area.
Treiman, J.A., 1993, The Rose Canyon Fault Zone, Southern California: California Geological
Survey, Open File Report 93-02.
United States Department of the Interior, Bureau of Reclamation, 1998, Engineering Geology
Field Manual.
United States Geological Survey, 2015, Encinitas Quadrangle, California, San Diego County,
7.5-Minute Series (Topographic): Scale 1:24,000.
United States Geological Survey, 2016, Seismic Design Maps Application,
http://earthquake.usgs.gov/designmaps/us/application.php: accessed in December.
AERIAL PHOTOGRAPHS
Source Date Flight Numbers Scale
United States Department of
Agriculture 4-11-53 AXN-8M 18 and 19 1:20,000
NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE
1_108064001_SL.mxd 1/20/2017 JDL8
5
805
15
SITE
MAP INDEX
San DiegoCounty
FIGURE
1PROJECT NO.DATE
1/17
SOURCE: ESRI WORLD TOPO, 2016
0 1,500 3,000
SCALE IN FEET
SITE LOCATION
108064001
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
B-2
TD=51.5B-1
TD=51.5
2_108064001_BL.mxd 1/20/2017 JDLNOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE.
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
BORING LOCATIONS FIGURE
2PROJECT NO.DATE
108064001 1/170120240
SCALE IN FEET
SOURCE: GOOGLE EARTH, 2016VISTA MARIANALEGEND
BORING
TD=TOTAL DEPTH IN FEETB-2
TD=51.5
M E X I C OUSAPacific O c e a n
NEVADA
CALIFORNIA
SAN
JACINTO
ELSINORE
IM
P
E
RIA
L
WHITTIER
NEWPORT-INGLEWOOD
C
O
R
O
N
A
D
O
B
A
N
K
S
A
N
DIE
G
O
T
R
O
U
G
H
SAN
CLEM
ENTE
S
A
N
TA
CRUZ-SANTACATALINARIDGE
P
A
L
O
S
VERDES
OFFSHORE ZONE
OF DEFORMATIONGARLOCKCLEARWATERS
AN
GABRIEL
SIERRAMADRE
BANNING
MISSION CREEK
B
LA
C
K
W
ATE
RHARPER
LOCKHART
LENW
O
O
D
CAMPROCK
CALIC
O LUDL
OW
PIS
GAHBULLION
MO
U
N
T
AIN
JO
HNS
O
N
VALLEY
E
M
ERSON
P IN T O M O U NTAINMANIX
MIRAGEVALLEY
NORTHHELENDALE
FRONTAL
CHIN
O
S A N J O S ECUCAMON G A
MALIBU COAST SA N T A MONICA
SANCAYETANO
SANTASUSANASANTAROSA
N O R T H R ID G E
C
HAR
NO
C
K
S A W P ITCAN Y O N
SUPERSTITIONHILLS
R
O
S
E
C
ANYONPINEMOUNTAIN
W HITEW O LFSAN ANDREAS FAULT ZONEPLEITOWHEELER
POSOCREEK
BLUE CUT
SALTON CREEK
SAN ANDREAS FAULT ZONECOYOTE
CREEK
CLARK
GLEN
IVY
EARTHQUAKE
VALLEY ELMORERANCHLAGUNA
SALADABRAWL
E
Y
SEI
SMI
CZ
ONE
San Bernardino County
Kern County
Riverside County
San Diego County
Imperial County
Los Angeles County
Inyo CountyTulare County
Ventura County
Orange County
CALIFORN IA
LEGEND
HOLOCENE ACTIVE
CALIFORNIA FAULT ACTIVITY
HISTORICALLY ACTIVE
LATE QUATERNARY (POTENTIALLY ACTIVE)
STATE/COUNTY BOUNDARY
QUATERNARY (POTENTIALLY ACTIVE)
NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE.
FAULT LOCATIONS FIGURE
3PROJECT NO.DATE
0 30 60
SCALE IN MILES
SOURCE: U.S. GEOLOGICAL SURVEY AND CALIFORNIA GEOLOGICAL SURVEY, 2006,
QUATERNARY FAULT AND FOLD DATABASE FOR THE UNITED STATES.3_108064001_FL.mxd 1/20/2017 11:38:11 AM JDLSITE
108064001 1/17
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE.
GEOLOGY FIGURE
4PROJECT NO.DATE
108064001 1/17
4_108064001_G.mxd 1/20/2017 JDL0 2,000 4,000
SCALE IN FEET
Mzu
REFERENCE: KENNEDY, M.P., TAN, S.S., BOVARD, K.R., ALVAREZ, R.M., WATSON, M.J.,AND GUTIERREZ, C.I., 2007, GEOLOGIC MAP OF THE OCEANSIDE30X60-MINUTE QUADRANGLE, CALIFORNIA
SITE
LEGEND
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
Td
D
H
Pa
+
NOTES:
APPARENT LATERAL EARTH PRESSURE, P
P = 50 H psf;
1.
CONSTRUCTION TRAFFIC INDUCED SURCHARGE PRESSURE, P
P = 120 psf
2.
3.
SURCHARGES FROM EXCAVATED SOIL OR5.
CONSTRUCTION MATERIALS ARE NOT INCLUDED
H/4
H/4
6.
Ps
a
s
a
s
FIGURE
5PROJECT NO.LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
DATE
LATERAL EARTH PRESSURES FOR BRACED
EXCAVATION BELOW GROUNDWATER (STIFF CLAY)
SHORING
BRACES
Pp
108064001 1/17
2
+
Pw
h
7.
4.
w
wP =62.4 (H - h) psf
HYDROSTATIC PRESSURE, P
GROUNDWATER TABLE
p
p
H, h AND D ARE IN FEET
PASSIVE LATERAL EARTH PRESSURE, P
P = 62 D + 400 psf
1 P = 25 H psfa2
1aP
5_108064001_d-lep_sc.dwg JDL
NOTES:
GROUNDWATER BELOW BLOCK
GROUNDWATER ABOVE BLOCK2.
1.
P = 175p (D -d )2 2 lb/ft
THRUST
BLOCK
d (VARIES)
P
Pp
p
D (VARIES)
3.ASSUMES BACKFILL IS GRANULAR MATERIAL
4.ASSUMES THRUST BLOCK IS ADJACENT TO COMPETENT MATERIAL
FIGURE
6PROJECT NO.DATE
THRUST BLOCK LATERAL EARTH PRESSURE DIAGRAM
1
Pp2
pP = 1.5 ( D - d )[ 124.8h + 57.6 ( D+d )]
GROUNDWATER TABLE6.
D, d AND h ARE IN FEET5.
h
lb/ft
108064001 1/176_108064001_d-tb.dwg P1 JDLLA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
La Costa Water Main Replacement January 27, 2017
Carlsbad, California Project No. 108064001
108064001 R.doc
APPENDIX A
BORING LOGS
Field Procedure for the Collection of Disturbed Samples
Disturbed soil samples were obtained in the field using the following method.
Bulk Samples
Bulk samples of representative earth materials were obtained from the exploratory excava-
tions. The samples were bagged and transported to the laboratory for testing.
The Standard Penetration Test (SPT) Sampler
Disturbed drive samples of earth materials were obtained by means of a Standard Penetra-
tion Test sampler. The sampler is composed of a split barrel with an external diameter of
2 inches and an unlined internal diameter of 1⅜ inches. The sampler was driven into the
ground 12 to 18 inches with a 140-pound hammer free-falling from a height of 30 inches in
general accordance with ASTM D 1586. The blow counts were recorded for every 6 inches
of penetration; the blow counts reported on the logs are those for the last 12 inches of pene-
tration. Soil samples were observed and removed from the sampler, bagged, sealed and
transported to the laboratory for testing.
Field Procedure for the Collection of Relatively Undisturbed Samples
Relatively undisturbed soil samples were obtained in the field using a modified split-barrel drive
sampler. The sampler, with an external diameter of 3.0 inches, was lined with 1-inch long, thin
brass rings with inside diameters of approximately 2.4 inches. The sample barrel was driven into
the ground with the weight of a 140-pound hammer, in general accordance with ASTM D 3550.
The driving weight was permitted to fall freely. The approximate length of the fall, the weight of
the hammer, and the number of blows per foot of driving are presented on the boring logs as an
index to the relative resistance of the materials sampled. The samples were removed from the
sample barrel in the brass rings, sealed, and transported to the laboratory for testing.
0
5
10
15
20
XX/XX
SM
CL
Bulk sample.
Modified split-barrel drive sampler.
2-inch inner diameter split-barrel drive sampler.
No recovery with modified split-barrel drive sampler, or 2-inch inner diameter split-barrel
drive sampler.
Sample retained by others.
Standard Penetration Test (SPT).
No recovery with a SPT.
Shelby tube sample. Distance pushed in inches/length of sample recovered in inches.
No recovery with Shelby tube sampler.
Continuous Push Sample.
Seepage.
Groundwater encountered during drilling.
Groundwater measured after drilling.
MAJOR MATERIAL TYPE (SOIL):Solid line denotes unit change.
Dashed line denotes material change.
Attitudes: Strike/Dip
b: Bedding
c: Contact
j: Joint
f: Fracture
F: Fault
cs: Clay Seam
s: Shear
bss: Basal Slide Surface
sf: Shear Fracture
sz: Shear Zone
sbs: Shear Bedding Surface
The total depth line is a solid line that is drawn at the bottom of the boring.
BORING LOG
Explanation of Boring Log Symbols
PROJECT NO. DATE FIGUREDEPTH (feet)BulkSAMPLESDrivenBLOWS/FOOTMOISTURE (%)DRY DENSITY (PCF)SYMBOLCLASSIFICATIONU.S.C.S.BORING LOG EXPLANATION SHEET
SOIL CLASSIFICATION CHART PER ASTM D 2488
PRIMARY DIVISIONS SECONDARY DIVISIONS
GROUP SYMBOL GROUP NAME
COARSE-
GRAINED
SOILS
more than
50% retained
on No. 200
sieve
GRAVEL more than 50% of coarse
fraction retained on No. 4 sieve
CLEAN GRAVELless than 5% fines
GW well-graded GRAVEL
GP poorly graded GRAVEL
GRAVEL with DUAL
CLASSIFICATIONS
5% to 12% fines
GW-GM well-graded GRAVEL with silt
GP-GM poorly graded GRAVEL with silt
GW-GC well-graded GRAVEL with clay
GP-GC poorly graded GRAVEL with clay
GRAVEL with FINES
more than 12% fines
GM silty GRAVEL
GC clayey GRAVEL
GC-GM silty, clayey GRAVEL
SAND 50% or more
of coarse fraction
passes No. 4 sieve
CLEAN SAND
less than 5% fines
SW well-graded SAND
SP poorly graded SAND
SAND with
DUAL CLASSIFICATIONS 5% to 12% fines
SW-SM well-graded SAND with silt
SP-SM poorly graded SAND with silt
SW-SC well-graded SAND with clay
SP-SC poorly graded SAND with clay
SAND with FINES more than
12% fines
SM silty SAND
SC clayey SAND
SC-SM silty, clayey SAND
FINE-
GRAINED
SOILS
50% or
more passes
No. 200 sieve
SILT and
CLAY liquid limit less than 50%
INORGANIC
CL lean CLAY
ML SILT
CL-ML silty CLAY
ORGANIC OL (PI > 4)organic CLAY
OL (PI < 4)organic SILT
SILT and CLAY liquid limit 50% or more
INORGANIC CH fat CLAY
MH elastic SILT
ORGANIC
OH (plots on or
above “A”-line)organic CLAY
OH (plots below “A”-line)organic SILT
Highly Organic Soils PT Peat
USCS METHOD OF SOIL CLASSIFICATION
Explanation of USCS Method of Soil Classification
PROJECT NO.DATE FIGURE
APPARENT DENSITY - COARSE-GRAINED SOIL
APPARENT
DENSITY
SPOOLING CABLE OR CATHEAD AUTOMATIC TRIP HAMMER
SPT (blows/foot)
MODIFIED SPLIT BARREL (blows/foot)
SPT (blows/foot)
MODIFIED SPLIT BARREL (blows/foot)
Very Loose < 4 < 8 < 3 < 5
Loose 5 - 10 9 - 21 4 - 7 6 - 14
Medium Dense 11 - 30 22 - 63 8 - 20 15 - 42
Dense 31 - 50 64 - 105 21 - 33 43 - 70
Very Dense > 50 > 105 > 33 > 70
CONSISTENCY - FINE-GRAINED SOIL
CONSIS-TENCY
SPOOLING CABLE OR CATHEAD AUTOMATIC TRIP HAMMER
SPT (blows/foot)
MODIFIED SPLIT BARREL
(blows/foot)
SPT (blows/foot)
MODIFIED SPLIT BARREL (blows/foot)
Very Soft < 2 < 3 < 1 < 2
Soft 2 - 4 3 - 5 1 - 3 2 - 3
Firm 5 - 8 6 - 10 4 - 5 4 - 6
Stiff 9 - 15 11 - 20 6 - 10 7 - 13
Very Stiff 16 - 30 21 - 39 11 - 20 14 - 26
Hard > 30 > 39 > 20 > 26
LIQUID LIMIT (LL), %PLASTICITY INDEX (PI), %0 10
107
4
20
30
40
50
60
70
0 20 30 40 50 60 70 80 90 100
MH or OH
ML or OLCL - ML
PLASTICITY CHART
GRAIN SIZE
DESCRIPTION SIEVE SIZE GRAIN SIZE APPROXIMATE SIZE
Boulders > 12”> 12”Larger than basketball-sized
Cobbles 3 - 12”3 - 12”Fist-sized to
basketball-sized
Gravel
Coarse 3/4 - 3”3/4 - 3”Thumb-sized to
fist-sized
Fine #4 - 3/4”0.19 - 0.75”Pea-sized to thumb-sized
Sand
Coarse #10 - #4 0.079 - 0.19”Rock-salt-sized to pea-sized
Medium #40 - #10 0.017 - 0.079”Sugar-sized to rock-salt-sized
Fine #200 - #40 0.0029 -
0.017”
Flour-sized to
sugar-sized
Fines Passing #200 < 0.0029”Flour-sized and
smaller
CH or OH
CL or OL
0
10
20
30
40
4
11
6
10
17
28
57
37
27.2
12.7
20.9
16.6
21.9
94.1
123.0
SM
SC
CL
SC
CL
SM
FILL:Dark brown, moist, medium dense, silty fine to medium SAND; scattered gravel and
cobbles up to approximately 8 inches in diameter.
Yellowish brown.Yellowish brown and olive (mottled), moist, medium dense, clayey fine to coarse sand.
YOUNG ALLUVIAL FLOOD PLAIN DEPOSITS:Dark gray, moist, soft to firm, fine to coarse, sandy CLAY; trace gravel; slight organic
odor.
Brown, wet, loose, clayey fine to coarse SAND; scattered rounded gravel up to 1/2-inch
in diameter.
Light grayish brown, wet, stiff, fine to coarse sandy CLAY; scattered rounded gravel up
to approximately 1-inch in diameter; some reddish brown staining.
Light brown; very stiff; scattered pockets of reddish brown sand.
Bluish gray; finely laminated.
Gravel layer.
Hard; scattered angular and subangular gravel up to approximately 1-inch in diameter.Difficult drilling from approximately 29 to 33 feet due to gravel and cobbles.
OLD ALLUVIAL FLOOD PLAIN DEPOSITS:Light gray and dark yellowish brown laminated, wet, dense to very dense, silty fine
SAND; micaceous; laminations approximately 1/4-inch thick; scattered manganese.
Light gray with scattered reddish brown staining. Slightly clayey.
BORING LOG
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
PROJECT NO.
108064001
DATE
1/17
FIGURE
A-1DEPTH (feet)BulkSAMPLESDrivenBLOWS/FOOTMOISTURE (%)DRY DENSITY (PCF)SYMBOLCLASSIFICATIONU.S.C.S.DESCRIPTION/INTERPRETATION
DATE DRILLED 12/12/16 BORING NO.B-1
GROUND ELEVATION 18' (MSL)SHEET 1 OF
METHOD OF DRILLING 8" Diameter Hollow Stem Auger (CME-75) (Baja Exploration)
DRIVE WEIGHT 140 lbs. (Auto-Trip Hammer)DROP 30"
SAMPLED BY CAT LOGGED BY CAT REVIEWED BY RDH
2
40
50
60
70
80
50/3"
50/6"
79/11"
DELMAR FORMATION:Light gray, wet, moderately to strongly cemented, silty fine-grained SANDSTONE;
abundant caliche throughout sample.
Dark gray and light gray laminated, wet, strongly indurated, fine-grained sandy
CLAYSTONE; laminations approximately 1/16-inch thick.
Light gray, wet, moderately to strongly cemented, silty fine-grained SANDSTONE;
micaceous.
Total Depth = 51.4 feet.
Groundwater encountered at approximately 10 feet during drilling.
Backfilled with approximately 16 cubic feet of bentonite grout shortly after drilling on
12/12/16.
Note: Groundwater may rise to a level higher than that measured in borehole due to
seasonal variations in precipitation and several other factors as discussed in the report.
The ground elevation shown above is an estimation only. It is based on our interpretations
of published maps and other documents reviewed for the purposes of this evaluation. It is
not sufficiently accurate for preparing construction bids and design documents.
BORING LOG
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
PROJECT NO.
108064001
DATE
1/17
FIGURE
A-2DEPTH (feet)BulkSAMPLESDrivenBLOWS/FOOTMOISTURE (%)DRY DENSITY (PCF)SYMBOLCLASSIFICATIONU.S.C.S.DESCRIPTION/INTERPRETATION
DATE DRILLED 12/12/16 BORING NO.B-1
GROUND ELEVATION 18' (MSL)SHEET 2 OF
METHOD OF DRILLING 8" Diameter Hollow Stem Auger (CME-75) (Baja Exploration)
DRIVE WEIGHT 140 lbs. (Auto-Trip Hammer)DROP 30"
SAMPLED BY CAT LOGGED BY CAT REVIEWED BY RDH
2
0
10
20
30
40
20
11
16
19
9
13
8
11
27.0
22.3
20.7
20.5
96.6
102.7
105.2
SM
SC
CL
SC
CL
SM
FILL:Reddish brown, moist, medium dense, silty fine to medium SAND; few gravel up to
approximately 1-inch in diameter.
Light brown; trace clay.
YOUNG ALLUVIAL FLOOD PLAIN DEPOSITS:Olive and light brown mottled, moist, medium dense, clayey fine to coarse SAND; trace
gravel.No recovery.
Dark gray to black, moist, stiff, fine sandy CLAY; few roothairs; scattered pinhole voids;
slight organic odor.
Dark gray and brown mottled; very stiff; fine to coarse sand.
Brown and gray mottled; scattered gravel up to approximately 2 inches in diameter.
Wet.
Brown with some gray mottling; stiff; scattered angular gravel up to approximately 1/2-
inch in diameter; scattered reddish brown and yellow staining.
Very stiff.
Grades to brown and gray mottled, wet, medium dense, clayey fine to coarse SAND;
scattered rounded gravel up to 1/2-inch in diameter; abundant reddish brown and yellow
staining.Brown and gray mottled, wet, stiff to very stiff, fine sandy CLAY; scattered rounded
gravel up to approximately 3/4-inch in diameter; scattered reddish brown staining.
Few interlayers of fine to coarse sand.
OLD ALLUVIAL FLOOD PLAIN DEPOSITS:Light gray, wet, medium dense to dense, silty fine SAND; micaceous.
BORING LOG
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
PROJECT NO.
108064001
DATE
1/17
FIGURE
A-3DEPTH (feet)BulkSAMPLESDrivenBLOWS/FOOTMOISTURE (%)DRY DENSITY (PCF)SYMBOLCLASSIFICATIONU.S.C.S.DESCRIPTION/INTERPRETATION
DATE DRILLED 12/13/16 BORING NO.B-2
GROUND ELEVATION 20' (MSL)SHEET 1 OF
METHOD OF DRILLING 8" Diameter Hollow Stem Auger (CME-75) (Baja Exploration)
DRIVE WEIGHT 140 lbs. (Auto-Trip Hammer)DROP 30"
SAMPLED BY CAT LOGGED BY CAT REVIEWED BY RDH
2
40
50
60
70
80
20
23
51
24.2 SM
SC
SM
OLD ALLUVIAL FLOOD PLAIN DEPOSITS: (Continued)Light gray, wet, medium dense to dense, silty fine SAND; micaceous.
Light gray and light brown laminated, wet, medium dense, clayey fine SAND; few low-
angle in-filled fractures.
Light brown, wet, dense, silty fine SAND; highly micaceous; few high angle fractures;
grades to fine to coarse.
Few laminations visible; some reddish brown staining.
Very dense.
Total Depth = 51.5 feet.
Groundwater encountered at approximately 18 feet during drilling.
Backfilled with approximately 16 cubic feet of bentonite grout shortly after drilling on
12/13/16.
Note: Groundwater may rise to a level higher than that measured in borehole due to
seasonal variations in precipitation and several other factors as discussed in the report.
The ground elevation shown above is an estimation only. It is based on our interpretations
of published maps and other documents reviewed for the purposes of this evaluation. It is
not sufficiently accurate for preparing construction bids and design documents.
BORING LOG
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
PROJECT NO.
108064001
DATE
1/17
FIGURE
A-4DEPTH (feet)BulkSAMPLESDrivenBLOWS/FOOTMOISTURE (%)DRY DENSITY (PCF)SYMBOLCLASSIFICATIONU.S.C.S.DESCRIPTION/INTERPRETATION
DATE DRILLED 12/13/16 BORING NO.B-2
GROUND ELEVATION 20' (MSL)SHEET 2 OF
METHOD OF DRILLING 8" Diameter Hollow Stem Auger (CME-75) (Baja Exploration)
DRIVE WEIGHT 140 lbs. (Auto-Trip Hammer)DROP 30"
SAMPLED BY CAT LOGGED BY CAT REVIEWED BY RDH
2
La Costa Water Main Replacement January 27, 2017
Carlsbad, California Project No. 108064001
108064001 R.doc
APPENDIX B
LABORATORY TESTING
Classification
Soils were visually and texturally classified in accordance with the Unified Soil Classification
System (USCS) in general accordance with ASTM D 2488. Soil classifications are indicated on
the logs of the exploratory borings in Appendix A.
In-Place Moisture and Density Tests
The moisture content and dry density of relatively undisturbed samples obtained from the ex-
ploratory borings were evaluated in general accordance with ASTM D 2937. The test results are
presented on the logs of the exploratory borings in Appendix A.
Gradation Analysis
Gradation analysis tests were performed on selected representative soil samples in general accord-
ance with ASTM D 422. The grain-size distribution curves are shown on Figures B-1 through B-4.
The test results were utilized in evaluating the soil classifications in accordance with the USCS.
Atterberg Limits
Tests were performed on selected representative soil samples to evaluate the liquid limit, plastic
limit, and plasticity index in general accordance with ASTM D 4318. These test results were uti-
lized to evaluate the soil classification in accordance with the Unified Soil Classification System
(USCS). The test results and classifications are shown on Figure B-5.
Direct Shear Tests
Direct shear tests were performed on representative samples in general accordance with ASTM
D 3080 to evaluate the shear strength characteristics of the selected material. The samples were
inundated during shearing to represent adverse field conditions. The test results are shown on
Figures B-6 through B-8.
Expansion Index Tests
The expansion index of selected materials was evaluated in general accordance with ASTM
D 4829. Specimens were molded under a specified compactive energy at approximately
50 percent saturation (plus or minus 1 percent). The prepared 1-inch thick by 4-inch diameter
specimens were loaded with a surcharge of 144 pounds per square foot and were inundated with
tap water. Readings of volumetric swell were made for a period of 24 hours. The results of these
tests are presented on Figure B-9.
La Costa Water Main Replacement January 27, 2017
Carlsbad, California Project No. 108064001
108064001 R.doc 2
Soil Corrosivity Tests
Soil pH and electrical resistivity tests were performed on representative samples in general ac-
cordance with CT 643. The chloride contents of the selected samples were evaluated in general
accordance with CT 422. The sulfate contents of the selected samples were evaluated in general
accordance with CT 417. The test results are presented on Figure B-10.
Coarse Fine Coarse Medium SILT CLAY
3" 2"¾"½" ⅜"4 8 3050
PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 422
108064001 1/17
B-1
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
Fine
Sample
Location
100
D10
16 200
GRAVEL SAND FINES
Symbol Plasticity
Index
Plastic
Limit
Liquid
Limit
1½" 1"
Depth
(ft)D30
B-1 5.0-9.0 -- -- --
Cu
--
USCS
--
D60
CL-- -- -- 55
Passing
No. 200
(%)
Cc
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0.00010.0010.010.1110100PERCENT FINER BY WEIGHTGRAIN SIZE IN MILLIMETERS
U.S. STANDARD SIEVE NUMBERS HYDROMETER
GRADATION TEST RESULTS
PROJECT NO. DATE
FIGURE
108064001_SIEVE B-1 @ 5.0-9.0.xls
Coarse Fine Coarse Medium SILT CLAY
3" 2"¾"½" ⅜"4 8 3050
PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 422
USCS
--
D60
SC-- -- -- 49
Passing
No. 200
(%)
Cc
B-1 15.0-16.5 41 17 24
Cu
--
GRAVEL SAND FINES
Symbol Plasticity
Index
Plastic
Limit
Liquid
Limit
1½" 1"
Depth
(ft)D30
Fine
Sample
Location
100
D10
16 200
108064001 1/17
B-2
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0.00010.0010.010.1110100PERCENT FINER BY WEIGHTGRAIN SIZE IN MILLIMETERS
U.S. STANDARD SIEVE NUMBERS HYDROMETER
GRADATION TEST RESULTS
PROJECT NO. DATE
FIGURE
108064001_SIEVE B-1 @ 15.0-16.5.xls
Coarse Fine Coarse Medium SILT CLAY
3" 2"¾"½" ⅜"4 8 3050
PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 422
USCS
--
D60
SC-- -- -- 40
Passing
No. 200
(%)
Cc
B-2 4.0-7.0 -- -- --
Cu
--
GRAVEL SAND FINES
Symbol Plasticity
Index
Plastic
Limit
Liquid
Limit
1½" 1"
Depth
(ft)D30
Fine
Sample
Location
100
D10
16 200
108064001 1/17
B-3
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0.00010.0010.010.1110100PERCENT FINER BY WEIGHTGRAIN SIZE IN MILLIMETERS
U.S. STANDARD SIEVE NUMBERS HYDROMETER
GRADATION TEST RESULTS
PROJECT NO. DATE
FIGURE
108064001_SIEVE B-2 @ 4.0-7.0.xls
Coarse Fine Coarse Medium SILT CLAY
3" 2"¾"½" ⅜"4 8 3050
PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 422
108064001 1/17
B-4
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
Fine
Sample
Location
100
D10
16 200
GRAVEL SAND FINES
Symbol Plasticity
Index
Plastic
Limit
Liquid
Limit
1½" 1"
Depth
(ft)D30
B-2 25.0-26.5 -- -- --
Cu
--
USCS
--
D60
CL-- -- -- 51
Passing
No. 200
(%)
Cc
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0.00010.0010.010.1110100PERCENT FINER BY WEIGHTGRAIN SIZE IN MILLIMETERS
U.S. STANDARD SIEVE NUMBERS HYDROMETER
GRADATION TEST RESULTS
PROJECT NO. DATE
FIGURE
108064001_SIEVE B-2 @ 25.0-26.5.xls
LOCATION
PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 4318
108064001 1/17
B-5
USCS
USCS
(Entire Sample)(Fraction Finer ThanLIMIT, PL INDEX, PI
LIQUID PLASTIC PLASTICITY
LIMIT, LL
B-2
B-2
26
30.0-31.5
44
40
20.0-21.5 18
21
No. 40 Sieve)
SYMBOL
15.0-16.5 2441
(FT)
DEPTH
17B-1
CLASSIFICATION
SC
CL
CL
CL
CL
CL19
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
CH or OH
CL or OL MH or OH
ML or OLCL - ML
0
10
20
30
40
50
60
0 102030405060708090100PLASTICITY INDEX, PI LIQUID LIMIT, LL
ATTERBERG LIMITS TEST RESULTS
PROJECT NO. DATE
FIGURE
108064001_ATTERBERG Page 1.xls
X
1/17
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
Ultimate5.0-6.5B-1
B-6
PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 3080
Sandy CLAY
108064001
Cohesion, c
(psf)
Friction Angle,
(degrees)Soil Type
CL35
35
210
CL
Description Symbol
Sample
Location
260
Depth
(ft)
Shear
Strength
5.0-6.5Sandy CLAY B-1 Peak
0
1000
2000
3000
0 1000 2000 3000SHEAR STRESS (PSF)NORMAL STRESS (PSF)
DIRECT SHEAR TEST RESULTS
PROJECT NO. DATE
FIGURE
108064001_DIRECT SHEAR B-1 @ 5.0-6.5.xls
X
1/17
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
Ultimate6.5-8.0B-2
B-7
PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 3080
Sandy CLAY
108064001
Cohesion, c
(psf)
Friction Angle,
(degrees)Soil Type
CL30
30
170
CL
Description Symbol
Sample
Location
200
Depth
(ft)
Shear
Strength
6.5-8.0Sandy CLAY B-2 Peak
0
1000
2000
3000
0 1000 2000 3000SHEAR STRESS (PSF)NORMAL STRESS (PSF)
DIRECT SHEAR TEST RESULTS
PROJECT NO. DATE
FIGURE
108064001_DIRECT SHEAR B-2 @ 6.5-8.0.xls
X
1/17
LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
Ultimate15.0-16.5B-2
B-8
PERFORMED IN GENERAL ACCORDANCE WITH ASTM D 3080
Sandy CLAY
108064001
Cohesion, c
(psf)
Friction Angle,
(degrees)Soil Type
CL20
20
460
CL
Description Symbol
Sample
Location
520
Depth
(ft)
Shear
Strength
15.0-16.5Sandy CLAY B-2 Peak
0
1000
2000
3000
4000
5000
0 1000 2000 3000 4000 5000SHEAR STRESS (PSF)NORMAL STRESS (PSF)
DIRECT SHEAR TEST RESULTS
PROJECT NO. DATE
FIGURE
108064001_DIRECT SHEAR B-2 @15.0-16.5.xls
PERFORMED IN GENERAL ACCORDANCE WITH
108064001 1/17
Low16.7 0.051 509.5 110.8
INITIAL COMPACTED
MOISTURE DRY DENSITY
(PCF)
POTENTIAL
(%) (IN)
INDEX EXPANSION
FINAL VOLUMETRIC
MOISTURE SWELL
EXPANSION
LOCATION
B-1
DEPTH
(FT)
5.0-9.0
(%)
SAMPLE SAMPLE
B-9
CARLSBAD, CALIFORNIA
LA COSTA WATER MAIN REPLACEMENT
EXPANSION INDEX TEST RESULTS
PROJECT NO. DATE
FIGURE
UBC STANDARD 18-2 ASTM D 4829
108064001_EXPANSION Page 1.xls
1 PERFORMED IN GENERAL ACCORDANCE WITH CALIFORNIA TEST METHOD 643
2 PERFORMED IN GENERAL ACCORDANCE WITH CALIFORNIA TEST METHOD 417
3 PERFORMED IN GENERAL ACCORDANCE WITH CALIFORNIA TEST METHOD 422
560 0.056
920 0.092
1/17 B-10LA COSTA WATER MAIN REPLACEMENT
CARLSBAD, CALIFORNIA
B-1 5.0-9.0 6.7
7.5
CHLORIDE
CONTENT 3
(ppm)
pH 1SAMPLE DEPTH
(FT)
SAMPLE
LOCATION (Ohm-cm)
RESISTIVITY 1 SULFATE CONTENT 2
(%)(ppm)
B-2 35.0-36.5 610
340
290
450
108064001
CORROSIVITY TEST RESULTS
PROJECT NO. DATE
FIGURE
108064001_CORROSIVITY Page 1.xls
La Costa Water Main Replacement January 27, 2017
Carlsbad, California Project No. 108064001
108064001 R.doc
APPENDIX C
LIQUEFACTION ANALYSES
3 115 25
3 115 NoLq
7 120 40
6 120 40
10 120 NoLq
17 120 NoLq
28 125 NoLq
57 125 25
70 130 NoLq
70 130 NoLq
70 130 NoLq
LiquefyPro CivilTech Software USA www.civiltech.comCivilTech Corporation
DYNAMIC SETTLEMENT ANALYSIS
La Costa Water Main Replacement
108064001 Plate A-1
Hole No.=B-1 Water Depth=5 ft Magnitude=6.9
Acceleration=0.45g
Raw Unit FinesSPT Weight %(ft)0
10
20
30
40
50
60
70
Shear Stress Ratio
CRR CSR fs1
Shaded Zone has Liquefaction Potential
0 1 Factor of Safety051Settlement
Saturated
Unsaturat.
S = 2.90 in.
0 (in.) 10
fs1=1
7 120 25
7 120 NoLq
11 120 NoLq
13 120 NoLq
9 120 NoLq
13 120 NoLq
8 120 NoLq
11 120 NoLq
20 125 25
23 125 25
51 130 25
LiquefyPro CivilTech Software USA www.civiltech.comCivilTech Corporation
DYNAMIC SETTLEMENT ANALYSIS
La Costa Water Main Replacement
108064001 Plate A-1
Hole No.=B-2 Water Depth=5 ft Magnitude=6.9
Acceleration=0.45g
Raw Unit FinesSPT Weight %(ft)0
10
20
30
40
50
60
70
Shear Stress Ratio
CRR CSR fs1
Shaded Zone has Liquefaction Potential
0 1 Factor of Safety051Settlement
Saturated
Unsaturat.
S = 1.16 in.
0 (in.) 10
fs1=1