HomeMy WebLinkAboutCT 14-08; WESTIN HOTEL & TIMESHARE; INFILTRATION FEASIBILITY CONDITION; 2016-08-23Geotechnical Engineering
Construction Inspection
RECEIVED Materials Testing
SEP 222016 Environmental
011zicE LOCATIONS
August 23, 2016 LAND DEVELOPMENT
ENGINEERING
SAN DiEGO
IMPERIAL COUNTY
6295 Ferris Square
Suite C
San Diego. CA 92121
Tel: 858.5373999
Fax: 858.537.3990
ORANGE COUNTY
CORPORATE BRANCH
2992 E. La Palma Avenue
Suite A
Anaheim, CA 92806
Tel: 7 14.632.2999
Fax: 714.632.2974
www.rnrgline.com
Grand Pacific Resorts, Inc. MTGL Project No: 1916A10
5900 Pasteur Court, Suite 200 MTGL Log No: 16-1613
Carlsbad, California 92008
Attention: Mr. Houston Arnold
Subject: INFILTRATION FEASIBILITY CONDITION
Lot 9 and CMWD Water Tank Site
Grand Pacific Resorts
Carlsbad, California
Reference: MTGL, Inc. (2014). Geotechnical Investigation, Lot 9 and CMWD
Water Tank Site, Grand Pacific Resorts, Carlsbad, California, MTGL
Project No. 1916A10, Log No. 14-1168, October 20.
City of Carlsbad (2016). BMP Design Manual, Form 1-8, completed by
MTGL, April 25, 2016.
Dear Mr. Arnold:
Per your request, we are providing information on the infiltration feasibility for the
Lot 9 and CMWD Water Tank Site project to be located at the Grand Pacific Resorts,
Carlsbad, California. We previously performed a geotechnical investigation of the site
and presented our results in the referenced report. We also completed Form 1-8 of the
City of Carlsbad BMP Design Manual.
The site contains undocumented fill materials that were placed during previous
grading activities. Due to the cultural deposits that exist at the site remedial grading to
remove all previously placed undocumented fill materials is not an option. As such,
there is a potential for adverse settlement and/or slope instability to develop if
significant amount of water is introduced into the subgrade at the site.
Any bio-retention basins, bio-swales, and other BMP's that are planned for the site
should be designed by the project civil engineer to prevent water infiltration in the
underlying soils.
INLAND EN! I'IUE
14467 Meridian Parkway
Building 2A
Riverside, CA 92518
Tel: 951.653.4999
Fax: 951.653.4666
INDlO
44917 Golf Center Pkwy
Suite I
Indio. CA 92201
Tel: 760.342.4677
Fax: 760.342.4525
OC/LA/INLAND EMPIRE
I)IsI'AlcFI
800.491.2990
SAN DiEGO I)isrticIi
888.844.5060
Lot 9 and CMWD Water Tank Site MTGL Project No. 1916A10
Carlsbad, California MTGL Log No. 16-1613
We appreciate this opportunity to be of continued service to you. Should you have any questions
regarding the information contained herein, please contact us at your earliest convenience.
Respectfully submitted,
MTGL, Inc.
f 4d
Sam E. Va'Iez, RCE 56226, RGE 2813
Vice President I Chief Engineer
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Geotechnical Engineering
Construction Inspection
Materials Testing
Environmental
LoCA'I'loNS
I
OFFICE
ORANGE COUNTY
BRANCH
I
CORPORATE
2992 E. La Palma Avenue
Suite A
Anaheim, CA 92806
Id: 714.632.2999
Fax: 714.632.2974
SAN DIEGO
IMPERIAl, CouNTs'
6295
Ferris Square
Suite C
San Diego, CA 92121
Tel: 858.537.3999
Fax: 858.537.3990
I INLAND EMPIRE
4467 Meridian Parkway
Building 2A
I
Riverside, CA 92518
Tel: 951.653.4999
Fax: 951.653.4666
INDlo
Ciolf Center Pkwy
I
44917
Suite I
Indio, CA 92201
Tel: 760.342.4677
I Fax: 760.342.4525
OC/LMNLND EMPIRE I DISPATCH
800.491.2990
I SAN DIEGO DISPATCH
I
888.844.5060
GEOTECHNICAL INVESTIGATION
Lot 9 and CMWD Water Tank Site
Grand Pacific Resorts
Carlsbad, California
Prepared For:
Grand Pacific Resorts
5900 Pasteur Court, Suite 200
Carlsbad, California 92008
Prepared By:
MTGL, Inc.
6295 Ferris Square, Suite C
San Diego, California 92121
October 20, 2014
MTGL Project No. 1916A10
MTGL Log No. 14-1168
SEGMENTAL RETAINING WALL
SOIL DESIGN PARAMETERS
Date: 27 May 2016 Job No. I 1916A10
Project: Lot 9 and CMWD Water Tank Site
Prepared By: MTGL, Inc. - Sam E. Valdez
Client: Grand Marbrisa Resorts
Soil Parameters Reinforced Retained Foundation
Internal Friction Angle: 310 280 25°
Cohesion (psf): 200
Moist Unit Weight (pcf): 125 125 125
Water should be prevented from infiltrating into the reinforced zone behind the wall. Our standard
design includes a 1' drain rock column behind the block, a 4" perforated drain at base of wall and a "burrito"
drain at the tail of the geogrid reinforcement. Are there any other drainage requirements?
Embedment requirements, distance to daylight?8 Feet - bottom outside edge
Design peak ground acceleration? 0.45g for walls greater than 6 feet high
Is a global stability analysis needed? (to be completed by the geotechnical engineer)Depends on wall height
Other design considerations?No
Temporary backcut constraints? 1:1 or flatter
beau ot iieaisierea
- - Company:
Engineer:
Date:
U
MTGL, Inc.
Sam E. Valdez
May 27, 2016
U No.C56226 I \ Exp,12-31-16
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Geotechnical Engineering
Construction Inspection
Materials Testing
Environmental
October 20, 2014
Grand Pacific Resorts
5900 Pasteur Court, Suite 200
Carlsbad, California 92008
Attention: Mr. Houston Arnold
Respectfully submitted,
MTGL, Inc.
Sam E. Valdez, RCE 56226, GE 2813
Vice Presidentiseerin
ES ioj
52C-13 ( GE 2813 1,fl J2/J
Expires 12 31
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MTGL Project No. 1916A10
MTGL Log No. 14-1168
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Engineering Geol ____
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Subject: GEOTECHNICAL INVESTIGATION
Lot 9 and CMWD Water Tank Site
Grand Pacific Resorts
Carlsbad, California
Dear Mr. Arnold:
In accordance with your request and authorization we have completed a
Geotechnical Investigation for the subject site. We are pleased to present the
following report which addresses both engineering geologic and geotechnical
conditions including a description of the site conditions, results of our field
exploration and laboratory testing, and our conclusions and recommendations for
grading and foundations design.
Based on our investigation, the site will be suitable for construction, provided the
recommendations presented herein are incorporated into the plans and specifications
for the proposed construction. Details related to geologic conditions, seismicity, site
preparation, foundation design, and construction considerations are also included in
the subsequent sections of this report.
We appreciate this opportunity to be of continued service and look forward to
providing additional consulting services during the planning and construction of the
project. Should you have any questions regarding this report, please do not hesitate
to contact us at your convenience.
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Lot 9 and CMWD Water Tank Site
Carlsbad, California
- Geotechnical Investigation MTGL Project No. 1916A10
MTGL Log No. 14-1168
I
TABLE OF CONTENTS
1 1.00 INTRODUCTION.........................................................................................................................1
1.01 PLANNED CONSTRUCTION ............................................................................................................1
I 1.02 SCOPE OF WORK ...........................................................................................................................1
1.03 SITE DESCRIPTION........................................................................................................................1
1.04 FIELD INVESTIGATION...................................................................................................................2
1 1.05 LABORATORY TESTING.................................................................................................................3
FINDINGS......................................................................................................................................4 I 2.00
2.01 REGIONAL GEOLOGIC CONDITIONS..............................................................................................4
2.02 SITE GEOLOGIC CONDITIONS ........................................................................................................ 4
I 2.03 GROUNDWATER CONDITIONS.......................................................................................................5
2.04 FAULTING AND SEISMICTY ............................................................................................................ 5
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2.05 LIQUEFACTION POTENTIAL...........................................................................................................6
2.06 LANDSLIDES..................................................................................................................................6
2.07 TSUNAMI AND SEICHE HAZARD .................................................................................................... 6
3.00 CONCLUSIONS...........................................................................................................................7
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3.01 GENERAL CONCLUSIONS...............................................................................................................7
3.02 EARTHQUAKE ACCELERATIONS \ CBC SEISMIC PARAMETERS....................................................7
3.03 ExPANSION POTENTIAL ................................................................................................................8
4.00 RECOMMENDATIONS.............................................................................................................9
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4.01 EXCAVATION CHARACTERISTICS/SHRINKAGE .............................................................................9
4.02 SETTLEMENT CONSIDERATIONS ...................................................................................................9
4.03 SITE CLEARING RECOMMENDATIONS.........................................................................................10
I 4.04 SITE GRADING RECOMMENDATIONS - COMPLETE REMOVAL OF UNDOCUMENTED FILLS........10
4.05 SITE GRADING RECOMMENDATIONS - CUT/FILL TRANSITION...................................................10
4.06 SITE GRADING RECOMMENDATIONS - PARTIAL REMOvAL OF UNDOCUMENTED FILLS............11
I 4.07 COMPACTION REQUIREMENTS....................................................................................................11
4.08 FILL MATERIALS .........................................................................................................................12
4.09 SWIMMING POOLS ....................................................................................................................... 12
4.10 SLOPES .........................................................................................................................................12 I 4.11 FOUNDATIONS.............................................................................................................................13
4.11.1 CONVENTIONAL SHALLOW FOUNDATIONS....................................................................13
I 4.11.2 CAST-IN-DRILLED-HOLE (CIDH) PILES ........................................................................ 13
4.12 CONCRETE SLABS ON GRADE AND MISCELLANEOUS FLATWORK.............................................14
4.13 PREWETTING RECOMMENDATION ..............................................................................................16
I 4.14 CORROSITIVITY...........................................................................................................................16
4.15 RETAINING WALLS .....................................................................................................................16
4.16 PAVEMENT DESIGN ..................................................................................................................... 18
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4.16.1 ASHALT CONCRETE ........................................................................................................ 18
I 4.16.2 PORTLAND CEMENT CONCRETE.....................................................................................18
4.17 CONSTRUCTION CONSIDERATIONS .............................................................................................19
I 4.17.1 MOISTURE SENSITIVE SOILS/WEATHER RELATED CONCERNS......................................19
4.17.2 DRAINAGE AND GROUNDWATER CONSIDERATIONS ......................................................19
4.17.3 TEMPORARY EXCAVATIONS AND SHORING....................................................................20
I 4.17.4 UTILITY TRENCHES ......................................................................................................... 22
4.17.5 SITE DRAINAGE ............................................................................................................... 22
4.18 GEOTECHMCAL OBSERVATION/TESTING OF EARTHWORK OPERATIONS ..................................22
1 5.00 LIMITATIONS ........................................................................................................................... 24
I ATTACHMENTS:
I Figure 1 - Site Plan
Figure 2— Geologic Cross Section
I Figure 3
Figure 4—
- Geologic Cross Section
Retaining Wall Drainage Detail
Appendix A - References
Appendix B - Field Exploration Program
Appendix C - Laboratory Test Procedures
Appendix D - Standard Earthwork and Grading Specifications
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Lot 9 and CMWD Water Tank Site - Geotechnical Investigation MTGL Project No. 1916A 10
Carlsbad, California MTGL Log No. 14-1168
1.00 INTRODUCTION
In accordance with your request and authorization, MTGL, Inc. has completed a Geotechnical
Investigation for the subject site. The following report presents a summary of our findings,
conclusions and recommendations based on our investigation, laboratory testing, and engineering
analysis.
1.01 PLANNED CONSTRUCTION
It is our understanding that the project will include construction of two four-story hotel buildings and
one three-story timeshare building with an underground parking lot. The structures are anticipated
to be supported by a conventional shallow foundation system with a slab-on-grade or by cast-in-
drilled-holes (CIDH) piles with a structural slab. Other improvements at the site are to include
automobile parking, concrete hardscape, swimming pool, and associate underground utilities.
1.02 SCOPE OF WORK
The scope of our geotechnical services included the following:
. Review of geologic, seismic, ground water and geotechnical literature.
Logging, sampling and backfilling of five exploratory borings drilled with an 8" hollow stem
auger drill rig to a maximum depth of 51 Y2 feet below existing grades and five exploratory
test pits with a backhoe to a maximum depth of 13'/2 feet below existing grade. Appendix B
presents a summary of the field exploration program.
Laboratory testing of representative samples (See Appendix Q.
Geotechnical engineering review of data and engineering recommendations.
Preparation of this report summarizing our findings and presenting our conclusions and
recommendations for the proposed construction.
1.03 SITE DESCRIPTION
The project is located on the Carlsbad Municipal Water District (CMWD) above ground water
storage tank site that is situated west of the northern end of The Crossing Drive in Carlsbad,
California. The Site Plan, Figure 1, shows the site and proposed development layout. Original
construction at the site consisted of creating a level pad for the above ground steel water storage
tank. It is our understanding that the water storage tank has been abandoned and is to be removed.
Based on information from a 2001 topographic map of the site the water storage tank sat at the top of
a hill at an elevation of about 261 feet msl. Slopes that descended from the site predominantly
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Lot 9 and CMWD Water Tank Site - Geotechnical Investigation MTGL Project No. 1916A10
Carlsbad. California MTGL Lo2 No. 14-1168
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projected in northeastern, eastern, and southwestern directions. The site was then graded to its
I current elevations as part of the grading operations associated with the Crossings Golf Course. It
was reported to us that the area east of the water storage tank was to be used as an over-flow
I automobile parking lot. At the time of our investigation we were not provided with any written
documentation, such as compaction or as-graded reports, of the grading operations that previously
occurred at the site.
I There is documentation that during the recent grading operations associated with the golf course
human remains and other archeological artifacts were exposed at the site in the area southeast of the
water storage tank. To protect the artifacts and remains in place a portion of the site was capped
with red colored cement/sand slurry followed by fill soils. During the field portion of our
investigation a separate exploration investigation, done by others, was underway at the site to help
identify the area of cement/sand slurry. The Site Plan shows the location of the exposed
cement/sand slurry which was provided to us by your office.
The current configuration of the site consists of a relatively level area around the water storage tank
with an elevation of about 262 feet msl (see Site Plan). The 'parking lot' area is unpaved with a high
elevation of 263 feet msl on the western side and 258 feet msl on the eastern side. Descending
slopes lead away from the site in northeastern, southeastern and western direction. A dirt access
road extends from The Crossing Drive to the western corner of the site, near the water storage tank.
Retaining walls that border the site on the western side are part of the Marbrisa Resorts
development.
1.04 FIELD INVESTIGATION
Prior to the field investigation, a site reconnaissance was performed by an engineer from our office
to mark the boring and test pit locations, as shown on the Site Plan, and to evaluate the borings and
test pits exploration locations with respect to obvious subsurface structures and access for the
drilling rig. Underground Service Alert was then notified of the marked location for utility clearance.
Our subsurface investigation consisted of drilling test borings utilizing a truck mounted drill rig
equipped with an 8" diameter hollow stem auger and excavating test pits with a backhoe. See
Appendix B for further discussion of the field exploration including logs of test borings and test pits.
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Borings were logged and sampled using Modified California Ring (Ring) and Standard Penetration
Test (SPT) samplers at selected depth intervals. Samplers were driven into the bottom of the boring
with successive drops of a 140-pound weight falling 30 inches. Blows required driving the last 12
I inches of the 18-inch Ring and SPT samplers are shown on the boring logs in the "blows/foot"
column (Appendix B). SPT was performed in the borings in general accordance with the American
I Standard Testing Method (ASTM) D1586 Standard Test Method. Representative bulk soil samples
were also obtained from our borings and test pits.
I Each soil sample collected was inspected and described in general conformance with the Unified
Soil Classification System (USCS). The soil descriptions were entered on the boring logs. All
I samples were sealed and packaged for transportation to our laboratory.
1.05 LABORATORY TESTING
Laboratory tests were performed on representative samples to verify the field classification of the
I recovered samples and to determine the geotechnical properties of the subsurface materials. All
laboratory tests were performed in general conformance with ASTM or State of California Standard
I Methods. The results of our laboratory tests are presented in Appendix C of this report.
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Carlsbad, California MTGL Log No. 14-1168
2.00 FINDINGS
2.01 REGIONAL GEOLOGIC CONDITIONS
The site is located in the coastal portion of the Peninsular Range Province of California. This area of
the Peninsular Range Province has undergone several episodes of marine inundation and subsequent
marine regression throughout the last 54 million years, which has resulted in the deposition of a
thick sequence of marine and nonmarine sedimentary rocks on the basement rock of the Southern
California Batholith. Gradual emergence of the region from the sea occurred in Pleistocene time,
and numerous wave-cut platforms, most of which were covered by relatively thin marine and
nonmarine terrace deposits, formed as the sea receded from the land. Accelerated fluvial erosion
during periods of heavy rainfall, coupled with the lowering of the base sea level during Quaternary
times, resulted in the rolling hills, mesas, and deeply incised canyons which characterize the
landforms in the general site vicinity today.
2.02 SITE GEOLOGIC CONDITIONS
As observed during this investigation, and our review of geotechnical maps, the site is underlain at
depth by Quaternary-aged Old Paralic Deposits, Unit 2-4 Undivided (Q0P24) and Tertiary-aged
Santiago Formation. Residual soils and undocumented fill materials were encountered above the
formational materials. Logs of the subsurface conditions encountered in our borings are provided in
Appendix B. Generalized descriptions of the materials encountered during this investigation are
presented below. Geologic cross sections are shown on Figure 2 and 3.
Undocumented fill soils were encountered in all borings and test pits, except for Boring B-3, and
ranged in depth from 11/2 to 41 feet below existing grade. As observed in our borings and test pits,
the fill materials consisted of light brown, brown, orange, and gray poorly graded sand (SP), Silty
Sand (SM) and Clayey Sand (SC). The sandy materials are fine to coarse grain, dry to moist, and
medium dense to dense. The fill materials also consisted of brown and dark brown Clay (CL) and
Fat Clay (CH). The clays are medium plasticity, moist and stiff to very stiff. The fills also contain
mixtures of Poorly Graded Sand with Clayey Sand (SP/SC) and Clayey Sand with Clay (SC/CL).
Gravel and trash were encountered within the fill materials. Since we do not have any
documentation of the placement of these fill materials the fills are considered undocumented and
unsuitable for structural support in their current condition.
Residual soils were encountered in Boring B-2 beneath the cement/sand slurry. The residual soils
consisted of brown Silty Sand (SM) that was fine grain, dry to moist, and loose. Some trash was
encountered within this layer. The residual soils layer is the zone of materials where the human
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Lot 9 and CMWD Water Tank Site - Geotechnical Investigation MTGL Project No. 1916A10
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remains and other archeological artifacts were previously found at the site. The residual soils are not
considered suitable for structural support in their current condition.
Pockets of trash and debris were encountered within the borings and test pits done as part of this
investigation and during the test pits performed for the cement/slurry investigation done by others.
The types of trash and debris encountered consisted of aluminum cans, glass, clothing, shoes, metal
piping and other miscellaneous trash.
Quaternary-aged Old Paralic Deposits, Unit 2-4 Undivided (QoP24 [formerly Terrace Deposits] was
encountered in four of the borings and one of the test pits at depths that ranged from existing ground
surface to 21 Y2 below existing grade. As observed in our explorations, the Old Paralic Deposits
consisted of orangish brown Silty Sandstone that was fine to medium grained, moist and moderately
cemented. In general, the Old Paralic Deposits have a very low expansive potential and are
considered suitable for support of structural loading in their current condition. ' Tertiary-aged Santiago Formation was encountered in one boring, B-i, at a depth of approximately
41 feet below existing grade. The Santiago Formation material encountered consisted of olive gray,
light brown and orange Silty Sandstone that was fine grained, moist, and moderately cemented. The
I Santiago Formation material is expected to underlie Old Paralic Deposits. In general, the sandy
materials of the Santiago Formation are considered suitable for support of structural loading in their
I current condition; however, there are highly expansive clayey portions of the formation that require
special handling during construction.
2.03 GROUNDWATER CONDITIONS
Seepage and/or groundwater were not observed in our investigation. However, it should be
recognized that excessive irrigation, or changes in rainfall or site drainage could produce seepage or
locally perched groundwater conditions within the soil underlying the site.
2.04 FAULTING AND SEISMICITY
Active earthquake faults are one of the most significant geologic hazards to development in
California. Active faults are those which have undergone surface displacement within the last
approximately 11,000 years. Potentially active faults show evidence of surface displacement within
the last approximately 1.6 million years. The site is not located within the Aiquist-Priolo Earthquake
Fault Zone and therefore surface rupture of an active fault is not considered to be a significant
geologic hazard at the site.
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Potential seismic hazards at the site are anticipated to be the result of ground shaking from distant
I active faults. The nearest known active fault is the Rose Canyon fault zone, which is located about
5.3 miles (8.5 km) southwest of the site. A number of other significant faults also occur in the San
I Diego metropolitan area suggesting that the regional faulting pattern is very complex. Faults such as
those offshore are known to be active and any could cause a damaging earthquake. The San Diego
metropolitan area has experienced some major earthquakes in the past, and will likely experience
I future major earthquakes.
2.05 LIQUEFACTION POTENTIAL
Liquefaction is a phenomenon where earthquake induced ground vibrations increase the pore
I pressure in saturated, granular soils until it is equal to the confining, overburden pressure. When this
occurs, the soil can completely lose its shear strength and become liquefied. The possibility of
I liquefaction is dependent upon grain size, relative density, confining pressure, saturation of the soils,
and strength of the ground motion and duration of ground shaking. In order for liquefaction to occur
three criteria must be met: underlying loose, coarse-grained (sandy) soils, a groundwater depth of
less than about 50 feet and a nearby large magnitude earthquake. Given the relatively dense nature
of the subsurface soils, and the absence of a groundwater table, the potential for liquefaction at the
site is considered to be negligible.
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2.06 LANDSLIDES
Since the existing slopes at the site were constructed with undocumented fill materials there is a high
I potential for landslides to occur within the fill materials at the site. The location and extent of the
landslides cannot be determined at this time. Remedial grading recommendations are presented in
this report to mitigate the potential for landslides at the site.
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2.07 TsUNAMI AND SEICHE HAZARD
The site is not located within an area mapped by the California Geological Survey as subject to
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inundation by tsunami. Given the location of the site at an elevation of approximately 260 feet
MSL, within a densely developed area, the inundation hazard posed by tsunami is considered to be
low. Seiches are not considered to be a hazard due the planned removal of the existing above-
ground water tank. There are no other nearby bodies of water impoundment.
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3.00 CONCLUSIONS
3.01 GENERAL CONCLUSIONS
Given the findings of the investigation, it appears that the site geology is suitable for the proposed
construction. Based on the investigation, it is our opinion that the proposed development is safe
against landslides and settlement provided the recommendations presented in our report are
incorporated into the design and construction of the project. Grading and construction of the
proposed project will not adversely affect the geologic stability of adjacent properties. The nature
and extent of the investigation conducted for the purposes of this declaration are, in our opinion, in
conformance with generally accepted practice in this area. Therefore, the proposed project appears
to be feasible from a geologic standpoint. There appears to be no significant geologic constraint
onsite that cannot be mitigated by proper planning, design, and sound construction practices.
Specific conclusions pertaining to geologic conditions are summarized below:
Due to proximity of the site to regional active and potentially active faults, the site could
experience moderate to high levels of ground shaking from regional seismic events within
the projected life of the building. A design performed in accordance with the current
California Building Code and the seismic design parameters of the Structural Engineers
Association of California is expected to satisfactorily mitigate the effects of future ground
shaking.
The potential for active (on-site) faulting is considered low.
The potential for liquefaction during strong ground motion is considered low.
The potential for landslides to occur is considered low if the remedial recommendations
presented herein are incorporated.
The on-site undocumented fill materials are considered not suitable for structural support in
their present condition. Recommendations are presented in the following sections for
remedial grading at the site.
The proposed structures may be supported by either a conventional shallow foundation
system if the undocumented fill materials are mitigated as recommended or by a deep
foundation system with reduced remedial grading requirements.
3.02 EARTHQUAKE ACCELERATIONS \ CBC SEISMIC PARAMETERS
The 2013 California Building Code seismic design parameters were obtained from the USGS
website using a project location of latitude 33.130 North and a longitude of 117.310 West. Based
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upon the anticipated grading requirements at the site a Site Class D was used for the project. The
1 2013 Seismic Design Parameters are presented below:
Ground Motion
Parameter Value
Ss 1.118g
Si 0.430g
Site Class D
SMS 1.177g
SMI 0.675g
SDS 0.7859
SDI 0.450g
3.03 ExPANSION POTENTIAL
The on-site soils possess a very low to medium expansion potential (Expansion Index of 0 to 71).
The on-site fill soil could be used for structural support but structural design criteria should be taken
into consideration for the on-site soil's medium expansion potential.
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4.00 RECOMMENDATIONS
Our recommendations are considered minimum and may be superseded by more conservative
requirements of the architect, structural engineer, building code, or governing agencies. The
foundation recommendations are based on the expansion index and shear strength of the onsite soils.
Import soils, if necessary should have a very low expansion potential (Expansion Index less than
20) and should be approved by the Geotechnical Engineer prior to importing to the site. In addition
to the recommendations in this section, additional general earthwork and grading specifications are
included in Appendix D.
4.01 EXCAVATION CHARACTERISTICS/SHRINKAGE
Our exploratory borings were advanced with little difficulty within the fill and residual soils and no
oversize materials were encountered in our subsurface investigation. Our exploratory borings were
advanced with some effort within the moderately cemented formational materials. Accordingly we
expect that all earth materials will be rippable with conventional heavy duty grading equipment with
experienced operations and that oversized materials are not expected.
1 Shrinkage is the decrease in volume of soil upon removal and recompaction expressed as a
percentage of the original in-place volume, which will account for changes in earth volumes that will
I occur during grading. Bulking is the increase in volume of soil upon removal recompaction
expressed as a percentage of the original in-place volume. Our estimate for shrinkage of the onsite
fill soils are expected to range from 5 to 10 percent. Our estimate for bulking of the formational
I materials is estimated to range from 5 to 10 percent. It should be noted that bulking and shrinkage
potential can vary considerably based on the variability of the in-situ densities of the materials in
I question.
I 4.02 SETTLEMENT CONSIDERATIONS
Based on the proposed grading recommendations, we anticipate that properly designed and
I constructed foundations that are supported on compacted fill materials will experience a total static
settlement of up to 1.0 inch with differential settlements of Y2 an inch. As a minimum, structures
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supported by shallow conventional foundations should be designed to accommodate a total
settlement of at least 1.0 inch with differential settlements of 1/2 an inch over a horizontal distance of
40 feet.
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4.03 SITE CLEARING RECOMMENDATIONS
All surface vegetation, trash, debris, asphalt concrete, Portland cement concrete and underground
I pipes should be cleared and removed from the proposed construction site. Underground facilities
such as utilities may exist at the site. Depressions resulting from the removal of foundations of
existing buildings, buried obstructions and/or tree roots should be backfllled with properly
I compacted material. All organics, debris, trash and topsoil should be removed from the grading area
and hauled offsite.
4.04 SITE GRADING RECOMMENDATIONS - COMPLETE REMOVAL OF UNDOCUMENTED FILLS
I Remedial grading at the site should include removal of all undocumented fills to expose undisturbed
formational materials (Old Paralic Deposits, Unit 2-4, Undivided or Santiago Formation). Based on
I information from the borings, removals may extend to about 41 feet below existing grade. The
bottom of the removals should then be evaluated by the geotechnical engineer or geologist to see if
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further remedial grading is warranted.
Once formational materials have been exposed and approved, the undocumented fill materials (with
I an expansion index of less than 50 and with no deleterious materials) may be placed as compacted
fill. Prior to fill placement, the exposed excavation bottom should be scarified to a depth of 8 to 12
inches, moisture conditioned and re-compacted. The materials should be compacted to at least 90 1 percent of the maximum dry density as determined by ASTM Test Method D1557 at a moisture
content that is slightly above optimum moisture content. Fill materials placed at a depth greater than
30 feet below finished grade should be compacted to a minimum of 95 percent of the maximum dry
density.
I Structures founded on soils that were prepared as described above may be supported by
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conventional slab-on-grade construction on a shallow foundation system.
4.05 SITE GRADING RECOMMENDATIONS - CUT/FILL TRANSITION
After remedial grading to remove all undocumented fill materials has been performed, there is a
potential within the individual building footprints to have a transition where footings rest both on
I undisturbed formational materials and compacted fill. This 'cut/fill' transition could result in
adverse differential settlement. To mitigate the cut/fill transition we recommend that the formational
I deposits within the cut portion of the building pad be over-excavated to a depth equal to one-half of
the maximum fill depth (but not less than 3 feet) of the fill portion of the building pad. The depths
are those measured from the bottom of the proposed footings. The over-excavated cut soils may
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then be placed as compacted fill. The purpose of the cut/fill mitigation is to provide a uniform fill of
at least 3 feet mat beneath all of the footings.
4.06 SITE GRADING RECOMMENDATIONS - PARTIAL REMOVAL OF UNDOCUMENTED FILLS
For structures which are planned to be supported by cast-in-drilled-hole (CIDH) pile foundation
system with structural slab, we recommend that remedial grading beneath the structure be performed
which includes over-excavation and re-compaction of the upper three feet of soils below finished
grade elevation. Prior to re-compaction of soils, the exposed excavation bottom should be scarified
to at least 8 to 12 inches, moisture conditioned, and compacted. The materials should be compacted
to a minimum of 90 percent of the maximum density at a moisture content that is slightly above
optimum.
For existing slopes that were constructed with undocumented fill materials, and are planned to be
left in place without remedial grading being performed, we recommend slope stabilization using
retaining walls supported by soils that have been remediated or CIDH piles. Once layout and extent
of slopes that are to be left in place have been identified MTGL should be contacted to provide slope
stability evaluation and mitigation alternatives.
For hardscape areas where remedial grading will not be performed we recommend that the upper
three feet of finished grade materials be removed and re-compacted. Prior to re-compaction of soils,
the exposed excavation bottom should be scarified to at least 8 to 12 inches, moisture conditioned,
and compacted. The materials should be compacted to a minimum of 90 percent of the maximum
density at a moisture content that is slightly above optimum. With this alternative there is a high
probability that adverse settlement will occur below hardscape. Recommendations are presented in
this report to help reduce the effects of such settlement.
4.07 COMPACTION REQUIREMENTS
All fill materials should be compacted to at least 90 percent of maximum dry density as determined
by ASTM Test Method D1557. Deep fill materials, those placed at a depth that is greater than 30
feet below finished grade, should be compacted to at least 95 percent of the maximum dry density as
determined by ASTM D1557. Fill materials should be placed in loose lifts, no greater than 8 inches
prior to applying compactive effort. All engineered fill materials should be moisture-conditioned and
processed as necessary to achieve a uniform moisture content that is slightly above optimum
moisture content and within moisture limits required to achieve adequate bonding between lifts.
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4.08 FILL MATERIALS
Removed and/or over-excavated soils may be reused as engineered fill except for expansive soils
(expansion index greater than 50) and soils containing detrimental amounts of organic material, trash
and other debris.
Imported materials shall be free from vegetable matter and other deleterious substances, shall not
contain rocks or lumps of a greater dimension than 4 inches, shall have an expansion index of less
than 20, and shall be approved by the geotechnical consultant. Soils of poor gradation, expansion, or
strength properties shall be placed in areas designated by the geotechnical consultant or shall be
removed off-site.
4.09 SWIMMING POOLS
Soils to be placed within five feet of planned swimming pool bottoms should have a low expansion
potential, expansion index less than 20. The low expansion potential should extend a minimum of
five feet beyond pool footprint.
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A 1 STnPF
Remedial grading at the site will include construction of new fill slopes. We recommend that slopes
be inclined no steeper than 2:1 (horizontal to vertical). Fills over sloping ground should be
constructed entirely on prepared bedrock. In areas where the existing ground surface slopes at more
than a 5:1 gradient, it should be benched to produce a level area to receive the fill. Benches should
be wide enough to provide complete coverage by the compaction equipment during fill placement.
Slopes constructed at 2:1 or flatter should be stable with regard to deep seated failure with a factor of
safety greater than 1.5, which is the generally accepted safety factor. However, all slopes are
susceptible to surficial slope failure and erosion, given substantial wetting of the slope face.
Surficial slope stability may be enhanced by providing proper site drainage. The site should be
graded so that water from the surrounding areas is not able to flow over the top of the slopes.
Diversion structures should be provided where necessary. Surface runoff should be confined to
gunite-lined swales or other appropriate devises to reduce the potential for erosion. It is
recommended that slopes be planted with vegetation that will increase their stability. Ice plant is
generally not recommended.
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4.11 FOUNDATIONS
The recommendations and design criteria are "minimum" in keeping with the current standard-of-
practice. They do not preclude more restrictive criteria by the governing agency or structural
considerations. The project structural engineer should evaluate the foundation configurations and
reinforcement requirements for actual structural loadings. The foundation design parameters
I assumes that remedial grading is conducted as recommended in this report, and that all the buildings
are underlain by a relatively uniform depth of compacted fill with a low to medium expansion
I potential. Note that expansion index testing should be conducted on the individual building pads
during finish grading in order to confirm this assumption.
I Conventional shallow foundations are considered suitable for support of the proposed structures
provided that remedial grading to remove undocumented fill materials and mitigation of cut/fill
I transitions are performed. If remedial grading is not performed, then proposed structures should be
supported by cast-in-drilled-hole (CIDH) piles.
4.11.1 CONVENTIONAL SHALLOW FOUNDATIONS
I Allowable Soil Bearing: 3,000 lbs/ft2 (allow a one-third increase for short-term wind
or seismic loads). The allowable soil bearing may be increase
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500 lbs/ft2 for every 12-inch increase in depth above the
minimum footing depth and 250 lbs/ft2 for every 12-inch
increase in width above the minimum footing width. The
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bearing value may not exceed 6,000 lbs/ft2
Minimum Footing Width: 24 inches
I Minimum Footing Depth: 24 inches below lowest adjacent soil grade
I Coefficient of Friction: 0.33
Passive Pressure: 350 psf per foot of depth. Passive pressure and the friction of
resistance could be combined without reduction
4.11.2 Cast-In-Drilled Hole (CIDH) PILES
I As an alternative to using a conventional shallow foundation system, which requires mitigation
of undocumented fill soils, structures at the site may be supported by cast-in-drilled hole
I (CIDH) piles extending a minimum of 10 feet into the formational materials (Old Paralic
Deposits, Unit 2-4, Undivided or Santiago Formation). The downward and uplift capacities of
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CIDH piles are presented below. The capacities are for dead plus live load; a one-third
I increase may be used when considering short-term wind or seismic loads. The capacities
recommended are based on the strength of the soils; the compressive and tensile strength of the
I CIDH piles should be verified by a structural engineer. CIDH piles in groups should be
spaced at least 2Y2 pile diameters on centers, but not less than three feet. If piles are spaced
accordingly, then no reduction in downward capacity of the piles due to group action is
I necessary.
CIDH Pile Size
(inches)
Downward Capacity
(kips)
Upward Capacity
(kips)
30 100 10
36 150 12
42 200 14
The lateral resistance of CIDH piles may be determined using the formulas in Section 1807A.3
I of the 2013 California Building Code. When using the formulas, a lateral bearing of 450 psf
per foot of depth may be used for that portion of the pile that is within formational materials,
I up to 4,500 psf. The passive resistance of the compacted/undocumented fill against CIDH pile
caps and grade beams may be assumed to be equal to the pressure developed by a fluid with a
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density of 200 pcf. A one-third increase in the passive value may be used for wind or seismic
loads. The resistance of the CIDH piles and the passive resistance of the soils may be
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combined without reduction in determining the total lateral resistance.
4.12 CONCRETE SLABS ON GRADE AND MISCELLANEOUS FLATWORK
I Interior slab-on-grade should be designed for the actual applied loading conditions expected. The
structural engineer should size and reinforce slabs to support the expected loads utilizing accepted
I methods of concrete design, such as those provided by the Portland Cement Association or the
American Concrete Institute. A modulus of subgrade reaction of 150 pounds per cubic inch (pci)
I could be utilized in design. Based on geotechnical consideration, interior slab for conventional slab-
on-grade design should be a minimum of 5 inches and should be reinforced with at least No. 4 bars
on 18 centers, each way. Actual reinforcement should be designed by the project structural engineer
I based upon medium expansion potential. Structural slabs should be designed by the structural
engineer and should span from foundation supports.
Concrete slabs constructed on soil ultimately cause the moisture content to rise in the underlying
soil. This results from continued capillary rise and the termination of normal evapotranspiration.
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Because normal concrete is permeable, the moisture will eventually penetrate the slab. Excessive
I moisture may cause mildewed carpets, lifting or discoloration of floor tiles, or similar problems. To
decrease the likelihood of problems related to damp slabs, suitable moisture protection measures
I should be used where moisture sensitive floor coverings, moisture sensitive equipment, or other
factors warrant.
A commonly used moisture protection in southern California consists of about 2 inches of clean
sand covered by at least 10 mil plastic sheeting. In addition, 2 inches of clean sand are placed over
the plastic to decrease concrete curing problems associated with placing concrete directly on an
impermeable membrane. However, it has been our experience that such systems will transmit from
approximately 6 to 12 pounds of moisture per 1,000 square feet per day. This may be excessive for
some applications, particularly for sheet vinyl, wood flooring, vinyl tiles, or carpeting with
impermeable backing that use water soluble adhesives. If additional moisture protection is needed,
then a Stego Wrap moisture barrier, or equivalent, may be used in lieu of 10 mil plastic sheeting.
The Stego Wrap should be installed per the manufacturers' recommendations.
Concrete is a rigid brittle material that can withstand very little strain before cracking. Concrete,
particularly exterior hardscape is subject to dimensional changes due to variations in moisture of the
concrete, variations in temperature and applied loads. It is not possible to eliminate the potential for
cracking in concrete; however, cracking can be controlled by use of joints and reinforcing. Joints
provide a pre-selected location for concrete to crack along and release strain and reinforcement
provides for closely spaced numerous cracks in lieu of few larger visible cracks. Crack control
joints should have a maximum spacing of 5 feet for sidewalks and 10 feet each way for slabs.
Differential movement between buildings and exterior slabs, or between sidewalks and curbs may be
decreased by doweling the slab into the foundation or curb.
Exterior concrete slabs on the expansive site soils may experience some movement and cracking.
Exterior slabs should be at least 4 inches thick and should be reinforce with at least 6x6, W2.9/W2.9
welded wire fabric or No. 4 bars spaced at 18 inches on center, each way, supported firmly at mid-
height of the slab.
Exterior slab areas where complete removal of undocumented fill materials was not performed
should be supported by concrete which is at least 5 inches thick with No. 4 bars spaced at 18 inches
on center. The slabs should be doweled into curbs and building foundations. The intent of this
recommendation is to minimize the potential for adverse settlement that may occur as a result of
leaving in undocumented fills.
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4.13 PREWETrING RECOMMENDATION
The soils underlying the slab-on-grade should be brought to a minimum of 2% and a maximum of
I 4% above their optimum moisture content for a depth of 12 inches prior to the placement of
concrete. The geotechnical consultant should perform insitu moisture tests to verify that the
appropriate moisture content has been achieved a maximum of 24 hours prior to the placement of
I concrete or moisture barriers.
4.14 CoRRoswn'Y
Corrosion series tests consisting of pH, soluble sulfates, soluble chlorides, and minimum resistivity
I were performed on selected samples of the on-site soils. Soluble sulfate levels for the on-site fill
soils indicate a negligible sulfate exposure for concrete structure. As such, no special considerations
I are required for concrete placed in contact with the on-site soils. However, it is recommended that
Type II cement to be used for all concrete.
I Based on the soluble chloride levels the on-site soils have a degree of corrosivity to metals that is
corrosive. Based on the pH and Resistivity, the on-site soils have a degree of corrosivity to ferrous
I metals that is moderately corrosive to very corrosive. The actual corrosive potential is determined
by many factors in addition to those presented herein. MTGL, Inc. does not practice corrosion
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engineering. Underground metal conduits in contact with the soil need to be protected. We
recommend that a corrosion engineer be consulted.
4.15 RETAINING WALLS
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Embedded structural walls should be designed for lateral earth pressures exerted on the walls. The
magnitude of these earth pressures will depend on the amount of deformation that the wall can yield
under the load. If the wall can yield sufficiently to mobilize the full shear strength of the soils, it
I may be designed for the active condition. If the wall cannot yield under the applied load, then the
shear strength of the soil cannot be mobilized and the earth pressures will be higher. These walls
I such as basement walls and swimming pools should be designed for the at rest condition. If a
structure moves towards the retained soils, the resulting resistance developed by the soil will be the
passive resistance.
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For design purposes, the recommended equivalent fluid pressure for each case for walls constructed
I above the static groundwater table, backfilled with low expansive soils, and where remedial grading
has been performed is provided below. Retaining wall backfill should be compacted to at least 90%
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relative compaction based on the maximum density defined by ASTM D1557. Retaining structures
may be designed to resist the following lateral earth pressures.
. Allowable Bearing Pressure - 3,000 psf
. Coefficient of Friction (Soil to Footing) - 0.33
Passive Earth Pressure - equivalent fluid weight of 300 pcf
(Maximum of 2,000 pcf)
At rest lateral earth pressure - 70 pcf
Active Earth Pressures - equivalent fluid weights:
Slope of Retained
Material
Equivalent Fluid Weight
(Pei)
Level 50
2:1 (H:V) 85
It is recommended that all retaining wall footings be embedded at least 24 inches below the lowest
adjacent finish grade. In addition, the wall footings should be designed and reinforced as required
for structural considerations.
Lateral resistance parameters provided above are ultimate values. Therefore, a suitable factor of
safety should be applied to these values for design purposes. The appropriate factor of safety will
depend on the design condition and should be determined by the project Structural Engineer. If any
super-imposed loads are anticipated, this office should be notified so that appropriate
recommendations for earth pressures may be provided.
Retaining structures should be drained to prevent the accumulation of subsurface water behind the
walls. Back drains should be installed behind all retaining walls exceeding 3.0 feet in height. A
typical detail for retaining wall back drains is presented as Figure 4. All back drains should be outlet
to suitable drainage devices. Walls and portions thereof that retain soil and enclose interior spaces
and floors below grade should be waterproofed and damp-proofed in accordance with the 2013
CBC.
For retaining walls exceeding 6 feet in height we recommend that a seismic retaining wall design be
conducted by the structural engineer. For seismic design we used a peak site acceleration of 0.45g
calculated from the modified seismic design parameters (Ss/2.5). For a retained wall condition, such
as the planned basement levels, we recommend a seismic load of 18H be used for design. The
seismic load is dependent of the retained wall height where H is the height of the wall, in feet, and
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the calculated triangular loads result in pounds per square foot exerted at the base of the wall and
zero at the top of the wall.
4.16 PAVEMENT DESIGN
Alternatives for asphalt or Portland cement concrete pavements are given below. Immediately prior
to constructing pavement sections, the upper 12 inches of pavement subgrade should be scarified,
brought to about optimum moisture content, and compacted to at least 95 percent of the maximum
I dry density as determined by ASTM D 1557. Aggregate base should also be compacted to at least
95 percent relative compaction. Aggregate base should conform to Caltrans Class II or Standard
Specifications for Public Works Constructions (SSPWC), Section 200 for crushed aggregate base. I Asphalt concrete should be compacted to at least 95 percent of the Hveem unit weight. Asphalt
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concrete should conform to SSPWC Section 400-4.
4.16.1 ASPHALT CONCRETE
Asphalt concrete pavement design was conducted in general accordance with Caltrans Design
Method (Topic 608.4). Two traffic types are anticipated at the site. These include areas of light
traffic and passenger car parking (Traffic Index of 4.5), and access and truck routes (Traffic
Index of 6.0). The project civil engineer should review these anticipated traffic levels to
determine if they are appropriate. Laboratory R-Value tests on the site soils indicate that an R-
Value of 15 may be used for preliminary pavement design. R-Value confirmation and final
pavement design should be performed on the finished soils within the pavement areas. The
following pavement sections would apply based on the Caltrans Design Method.
Traffic Index Asphalt Thickness TBase Thickness
4.5 4 inches 4 inches
6.0 4 inches 91/2 inches
4.16.2 PORTLAND CEMENT CONCRETE
Concrete pavement design was conducted in accordance with the simplified design procedure of
the Portland Cement Association. This methodology is based on a 20 year design lift. For
design, it was assumed that aggregate interlock would be used for load transfer across control
joints. Laboratory R-Value tests indicate that the subgrade materials will provide a 'low'
subgrade support. Based on these assumptions, we recommend that the pavement section
consist of 6 inches of Portland cement concrete over native subgrade. This PCC section is
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applicable for both truck traffic areas and passenger car parking areas. Crack control joints
should be constructed for all PCC pavements on a maximum of 10 foot centers, each way.
Concentrated truck traffic areas, such as trash truck aprons, should be reinforced with at least
No. 4 bars on 18-inch centers, each way.
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4.17 CONSTRUCTION CONSIDERATIONS
4.17.1 MOISTURE SENSITIVE SOILS/WEATHER RELATED CONCERNS
The upper soils encountered at this site may be sensitive to disturbances caused by construction
traffic and to changes in moisture content. During wet weather periods, increases in the moisture
content of the soil can cause significant reduction in the soil strength and its support capabilities.
In addition, soils that become excessively wet may be slow to dry and thus significantly delay
the progress of the grading operations. Therefore, it will be advantageous to perform earthwork
and foundation construction activities during the dry season. Much of the on-site soils may
be susceptible to erosion during periods of inclement weather. As a result, the project Civil
Engineer/Architect and Grading Contractor should take appropriate precautions to reduce the
potential for erosion during and after construction.
4.17.2 DRAINAGE AND GROUNDWATER CONSIDERATIONS
No groundwater was encountered within the maximum explored depth of 51 V2 feet below
existing grade. It should be noted, however, that variations in the ground water table may result
from fluctuation in the ground surface topography, subsurface stratification, precipitation,
irrigation, and other factors that may not have been evident at the time of our exploration.
Seepage sometimes occurs where relatively impermeable and/or cemented formational materials
are overlain by fill soils. We should be consulted to evaluate areas of seepage during
construction.
Water should not be allowed to collect in the foundation excavation, on floor slab areas, or on
prepared subgrades of the construction area either during or after construction. Undercut or
excavated areas should be sloped to facilitate removal of any collected rainwater, groundwater,
or surface runoff. Positive site drainage should be provided to reduce infiltration of surface
water around the perimeter of the building and beneath the floor slabs. The grades should be
sloped away from the building and surface drainage should be collected and discharged such that
water is not permitted to infiltrate the backfill and floor slab areas of the building.
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4.17.3 TEMPORARY EXCAVATIONS AND SHORING
Short term temporary excavations in existing soils may be safely made at an inclination of 1:1
I (horizontal to vertical) or flatter. If vertical sidewalls are required in excavations greater than 3
feet in depth, the use of cantilevered or braced shoring is recommended. Excavations less than 3
feet in depth may be constructed with vertical sidewalls without shoring or shielding. Our
I recommendations for lateral earth pressures to be used in the design of cantilevered and/or
braced shoring are presented below. These values incorporate a uniform lateral pressure of 72
I psf to provide for the normal construction loads imposed by vehicles, equipment, materials, and
workmen on the surface adjacent to the trench excavation. However, if vehicles, equipment,
materials, etc. are kept a minimum distance equal to the height of the excavation away from the
I edge of the excavation, this surcharge load need not be applied.
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P Total = 72 psf + 30 H pot
P. = 25 H psi 72 osf
P Total = 72 psf+ 25 H psf
SHORING DESIGN: LATERAL SHORING PRESSURES
Design of the shield struts should be based on a value of 0.65 times the indicated pressure, Pa,
I for the approximate trench depth. The wales and sheeting can be designed for a value of 2/3 the
design strut value.
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11 H1
STRUTS—,:. D
(typ.)
HSh
SHIELD
(typ.)
UNDISTURBED
SOIL—
BEDDING P, = 30 HSh psf
HEIGHT OF SHIELD, HSh = DEPTH OF TRENCH, D MINUS DEPTH OF SLOPE, H1
TYPICAL SHORING
DETAIL
Placement of the shield may be made after the excavation is completed or driven down as the
material is excavated from inside of the shield. If placed after the excavation, some over-
excavation may be required to allow for the shield width and advancement of the shield. The
shield may be placed at either the top or the bottom of the pipe zone. Due to the anticipated
thinness of the shield walls, removal of the shield after construction should have negligible
effects on the load factor of pipes. Shields may be successively placed with conventional
trenching equipment.
Vehicles, equipment, materials, etc. should be set back away from the edge of temporary
excavations a minimum distance of 15 feet from the top edge of the excavation. Surface waters
should be diverted away from temporary excavations and prevented from draining over the top
of the excavation and down the slope face. During periods of heavy rain, the slope face should
be protected with sandbags to prevent drainage over the edge of the slope, and a visqueen liner
placed on the slope face to prevent erosion of the slope face.
Periodic observations of the excavations should be made by the geotechnical consultant to verify
that the soil conditions have not varied from those anticipated and to monitor the overall
condition of the temporary excavations over time. If at any time during construction conditions
are encountered which differ from those anticipated, the geotechnical consultant should be
contacted and allowed to analyze the field conditions prior to commencing work within the
excavation. All Ca1IOSHA construction safety orders should be observed during all
underground work.
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I 4.17.4 UTILITY TRENCHES
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A!! CaIIOSHA construction safety orders should be observed during all underground work. All
utility trench backfill within street right of way, utility easements, under or adjacent to
sidewalks, driveways, or building pads should be observed and tested by the geotechnical
I consultant to verify proper compaction. Trenches excavated adjacent to foundations should not
extend within the footing influence zone defined as the area within a line projected at a 1:1
I (horizontal to vertical) drawn from the bottom edge of the footing. Trenches crossing
perpendicular to foundations should be excavated and backfilled prior to the construction of the
foundations. The excavations should be backfilled in the presence of the geotechnical engineer
I and tested to verify adequate compaction beneath the proposed footing.
I Utilities should be bedded and backfilled with clean sand or approved granular soil to a depth of
at least 1-foot over the pipe. The bedding materials shall consist of sand, gravel, crushed
I
aggregate, or native, free draining soils with a sand equivalence of not less than 30. The bedding
should be uniformly watered and compacted to a firm condition for pipe support.
I The remainder of the backfill shall be typical on-site soil or imported soil which should be
placed in lifts not exceeding 8 inches in thickness, watered or aerated to near optimum moisture
content, and mechanically compacted to at least 90% of maximum dry density (ASTM D1557).
4.17.5 SITE DRAINAGE
I The site should be drained to provide for positive drainage away from structures in accordance
I with the building code and applicable local requirements. Unpaved areas should slope no less
than 2% away from structure. Paved areas should slope no less than 1% away from structures.
I
Concentrated roof and surface drainage from the site should be collected in engineered, non-
erosive drainage devices and conducted to a safe point of discharge. The site drainage should be
I
designed by a civil engineer.
4.18 GEOTECHMCAL OBSERVATION/TESTING OF EARTHWoRK OPERATIONS
I The recommendations provided in this report are based on preliminary design information and
subsurface conditions as interpreted from the investigation. Our preliminary conclusion and
I recommendations should be reviewed and verified during site grading, and revised accordingly if
exposed Geotechnical conditions vary from our preliminary findings and interpretations. The
I
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Lot 9 and CMWD Water Tank Site - Geotechnical Investigation MTGL Project No. 1916A10
Carlsbad, California MTGL Log No. 14-1168
I
Geotechnical consultant should perform Geotechnical observation and testing during the following
I phases of grading and construction:
I . During site grading and over-excavation.
. During foundation excavations and placement.
I . Upon completion of retaining wall footing excavation prior to placing concrete.
. During excavation and backfihling of all utility trenches
During processing and compaction of the subgrade for the access and parking areas and I prior to construction of pavement sections.
. When any unusual or unexpected Geotechnical conditions are encountered during any
I phase of construction.
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Lot 9 and CMWD Water Tank Site - Geotechnical Investigation MTGL Project No. 1916A10
Carlsbad, California MTGL Log No. 14-1168
5.00 LIMITATIONS
The findings, conclusions, and recommendations contained in this report are based on the site
I conditions as they existed at the time of our investigation, and further assume that the subsurface
conditions encountered during our investigation are representative of conditions throughout the site.
Should subsurface conditions be encountered during construction that are different from those
I described in this report, this office should be notified immediately so that our recommendations may
be re-evaluated.
This report was prepared for the exclusive use and benefit of the owner, architect, and engineer for
evaluating the design of the project as it relates to geotechnical aspects. It should be made available
to prospective contractors for information on factual data only, and not as a warranty of subsurface
conditions included in this report.
Our investigation was performed using the standard of care and level of skill ordinarily exercised
under similar circumstances by reputable soil engineers and geologists currently practicing in this or
similar localities. No warranty, express or implied, is made as to the conclusions and professional
advice included in this report.
This firm does not practice or consult in the field of safety engineering. We do not direct the
Contractor's operations, and we are not responsible for their actions. The contractor will be solely
and completely responsible for working conditions on the job site, including the safety of all persons
and property during performance of the work. This responsibility will apply continuously and will
not be limited to our normal hours of operation.
I The findings of this report are considered valid as of the present date. However, changes in the
conditions of a site can occur with the passage of time, whether they are due to natural events or to
I human activities on this or adjacent sites. In addition, changes in applicable or appropriate codes
and standards may occur, whether they result from legislation or the broadening of knowledge.
I Accordingly, this report may become invalidated wholly or partially by changes outside our control.
Therefore, this report is subject to review and revision as changed conditions are identified.
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I FIGURES
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/
/
/
/
KEY:
- 8-5 Boring Number and Approximate Location
- FM- FM - Approximate Depth to Formational Soils
-
)ç.
TO-
01. TD - Total Depth
OT - Approximate Depth to 2001 Existing Grade
(NE- Not Encountered)
I - \ \
ip Test Pit Number and Approximate Location
FM- FM - Approximate Depth to Formational Soils
TO- TD - Total Depth OT-
- \ OT - Approximate Depth to 2001 Existing Grade
\ . (NE - Not Encountered)
- C C
Geologic Cross Section
•
-,
Ii
L---. i:--
-
I i -
----I, I
- r - ---- - - ....' I
REFERENCE:
- .i, ':i) 1ll =60
SITE PLAN
PROJECT NO. 1916A10
MTGL, INC LOG NO. 14-1168
FIGURE 1 Plan by Excel Engineering, undated.
M =M mom — — — — — — — — — — — — —
A
275-
A'
.275
270-
-
I
PROPOSED HOTEL BUILDING
9-2
PROPOSED HOTEL BUILDING
270
9-I
FILL 205
- / ?
- \ FILL X Forn,3tlonol Contost -250
>
1220i
—
— Gop2-4 N 5.
0 Z
z
—
- 2001 ode 240
(0
2 / l9W
/ —
230- W
- FILL
KEY:
220 - .220 B-5 - Boring Number
TP-5 - Test Pit Number
- Tsa FO - Approximate Depth to Formational Soils
210- -210 TO - Total Depth
FILL - Undcoumented Fill
205- 10-51W .200 Qop24 - Old Paralic Deposits, Unit 24 Undivided
N _ Tsa - Santiago Formation
Horizontal Scale: 1" = 60
Vertical Scale: 1° = 15
am
FIGURE 2
- - - - - - - - - - - - - - - -
GEOLOGIC CROSS SECTION
PROJECT NO. 1916A10
MTGL, INC LOG NO. 14-1168
E 3fl9Id
99 - ON 901 3N1 '101W
0V96 ON 133f0Id
N0113S SSOI3 3I00100
P10P!A!PUfl i'-Z !Ufl 's!sodea 011eJed PlO -
lI!d P9WWflOPUfl - liki
qd9O I4Oi - ai SIlOS leuoilewjo=l oj qdoa 9ew!xoJddy -
JqwnJ Md IS91 - 9-di
jaqwnN 6uuo - 9-9
:)4
014
.14)4-1
0)4
044
1414-4) 400)043 4)004)04)104
022 -
—
\0p0 JD LOU
42
0P044 01d
\ I0 on
0NIauna 314VH3v4tL
0
4)0)043 l°0)04 z .4
042 Iz ---
11
on
111j 13A31 iN33SY14 3HV14S WILL
0p444 1002 062
4-dO OS Wi DE 4>
oNlcrllne 314V4S3V41J.
Ca
5)4
9
P1
044:;;
012
w
4P0 0)14) /
— — man — — — — I-i — we — — — — — — —m
.91. = I. :GleDS IOflJ9A =J :elsos IC°!P3A
.09 = (. :e3$ IiUOZUOH ,09=J :81e5 I101UOZUOH
MN - MS
Lot 9 and CMWD Water Tank Site - Geotechnical Investigation MTGL Project No. 1916A10
Carlsbad, California MTGL Log No. 14-1168
Soil backfill, compacted to
Retaining wall 90% relative compaction*
Wall waterproofing
per architects
specifications
Provide open cell head
joints or outlet drain at
50 feet on center to a
suitable drainage device
Filter fabric envelope
(Mirafi 140N or approved
equivalent) **
Minimum of 1 cubic foot
- per linear foot of 3/4
crushed rock
o 3" diameter perforated
I PVC pipe (schedule 40 or
0 equivalent) with perforations
oriented down as depicted
0 .00 Y mm. minimum 1% gradient to
-,
suitable outlet.
* Based on ASTM D1557
Compacted fill I
Wall footing
0
If class 2 permeable material (See
gradation to left) is used in place of
3/4" - 1 1/2 gravel. Filter fabric may
be deleted. Class 2 permeable material
compacted to 90% relative compaction. *
SPECIFICATIONS FOR CLASS 2
PERMEABLE MATERIAL
(CAL TRANS SPECIFICATIONS)
Sieve Size % Passing
1" 100
3/4" 90-100
3/8 40-100
No.4 25-40
No.8 18-33
No.30 5-15
No.50 0-7
No.200 0-3
RETAINING WALL DRAINAGE DETAIL
Figure 4
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APPENDIX A
REFERENCES I
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Lot 9 and CMWD Water Tank Site - Geotechnical Investigation MTGL Project No. 1916A10
Carlsbad, California MTGL Log No. 14-1168
I
APPENDIX A
REFERENCES
I Anderson, J.G., Rockwell, T.K., Agnew, D.0 (1989). Past and Possible Future Earthquakes of
Significance to the San Diego Region, Earthquake Spectra, Vol. 4, No. 2, pp 299-335.
California Building Standards Commission (2013). 2013 California Building Code, July 2013.
I California Division of Mines and Geology, 1997, Fault-Rupture Hazard Zones in California,
Special Publication 42.
I California Geological Survey, 2008, Guidelines for Evaluating and Mitigating Seismic Hazards in
California, Special Publication 117.
I Kennedy, Michael P. and Siang Tan (2005). Geologic Map of the Oceanside 30' x 60'
Quadrangle, California, USGS Digitally Prepared.
I Seed, H.B. and Whitman, R.V., 1970, Design of Earth Structures for Dynamic Loads in ASCE
Specialty Conference, Lateral Stresses in the Ground and Design of Earth-Retaining
I
Structures.
U.S. Geologic Survey (2010). Design Maps, http://geohazards.usgs.gov/designmpas/us.
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APPENDIX B
I FIELD EXPLORATION PROGRAM
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Lot 9 and CMWD Water Tank Site - Geotechnical Investigation MTGL Project No. 1916A10
Carlsbad, California MTGL Log No. 14-1168
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APPENDIX B
FIELD EXPLORATION PROGRAM
The subsurface conditions for this Geotechnical Investigation were explored by excavating five (5)
exploratory borings and five (5) exploratory trenches. The exploratory borings were excavated
using an 8-inch diameter hollow-stem-auger to a maximum depth of 51 V2 feet below existing grade.
The exploratory trenches were excavated using a 416E backhoe to a maximum depth of 13 '/2 below
I existing grade. The approximate locations of the borings and test pits are shown on the Site Plan
(Figure 1). The field exploration was performed under the supervision of our engineer who
maintained a continuous log of the subsurface soils encountered and obtained samples for
I laboratory testing. All drive samples were obtained by SPT or California Tube Sampler.
I Subsurface conditions are summarized on the accompanying Logs of Borings. The logs contain
factual information and interpretation of subsurface conditions between samples. The stratum
I indicated on these logs represents the approximate boundary between earth units and the transition
may be gradual. The logs show subsurface conditions at the dates and locations indicated, and may
not be representative of subsurface conditions at other locations and times.
Identification of the soils encountered during the subsurface exploration was made using the field
identification procedure of the Unified Soils Classification System (ASTM D2488). A legend
indicating the symbols and definitions used in this classification system and a legend defming the
terms used in describing the relative compaction, consistency or firmness of the soil are attached in
this appendix. Bag samples of the major earth units were obtained for laboratory inspection and
testing, and the in-place density of the various strata encountered in the exploration was determined
The exploratory borings were located in the field by using cultural features depicted on a
preliminary site plan provided by the client. Each location should be considered accurate only to
the scale and detail of the plan utilized.
The exploratory borings were backfilled in accordance with State of California regulations which
incorporated compacting soil cuttings and bentonite chips.
1]
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Lot 9 and CMWD Water Tank Site - Geotechnical Investigation MTGL Project No. 1916A10
Carlsbad, California MTGL Log No. 14-1168
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UNIFIED SOIL CLASSIFICATION SYSTEM
GRAVELS Clean Gravels (less GW Well-graded gravels, gravel-sand mixtures,
are more than half of than 5% fines) little or no fines r
Gravels fines with GP Poorly-graded gravels, gravel-sand mixtures, coarse fraction larger
than #4 sieve little or no fines
SANDS Clean Sands (less Silty Gravels, poorly-graded gravel-
Z are more than half of than 5% fines) GM sand-silt mixtures
- 0 — b ç A coarse fraction larger Clayey Gravels, poorly-graded gravel-
- than #4 sieve Sands with fines GC sand-clay mixtures
Well-graded sands, gravelly sands,
0 SW little or no fines
Poorly-graded sands, gravelly sands, SP little or no fines SILTS AND CLAYS Silty Sands, poorly-graded sands- Liquid Limit SM gravel-clay mixtures
C) Less than 50 Clayey Sands, poorly-graded sand-
rID '
SC gravel-silt mixtures
ca
0 0
—r1 ML Inorganic clays of low to med plasticity,
A gravelly, sandy, silty, or lean clays
CA . Inorganic clays of low to med plasticity, CL gravelly, sandy, silty, or lean clays
Organic silts and clays E
)
OL of low plasticity SILTS AND CLAYS Inorganic silts, micaceous or diatomaceous Liquid Limit N'IH fine sands or silts Greater than 50 Inorganic clays of high plasticity, CH fat clays
Organic silts and clays of medium OH to highplasticity
Highly Organic Soils PT Peat, humus swamp soils with
high organic content
GRAIN SIZE SIZE PROPORTION
Description Sieve Size Grain Size Approximate Size Trace - Less than 5%
Boulders >12" >12" Larger than basketball-sized Few -5% to 10%
Cobbles 3"- 12" 3"- 12" Fist-sized to basketball-sized Little - 15% to 20%
Coarse %"- 3" 3/4"- 3" Thumb-sized Some - 30% to 45% Gravel Fine #4 - 1/4" 0.19"- 0.75" Peat-sized to thumb-sized Mostly - 50% to 100%
Coarse #10 - #4 0.079" - 0.19" Rock salt-sized to pea-sized MOISTURE CONTENT
Sand Medium #40 - #10 0.017" - 0.079" Sugar-sized to rock salt-sized Dry - Absence of moisture
Fine #200 - #40 0.0029" - 0.017" Flour-sized to sugar-sized Moist - Damp but not visible
Fines Passing #200 <0.0029" Flour-sized or smaller Wet - Visible free water
CONSISTENCY FINE GRAINED SOILS RELATIVE DENSITY COARSE GRAINED SOILS
Apparent
Density
SPT
(Blows/Foot)
Mod CA Sampler
(Blows/Foot)
Apparent
Density
SPT
(Blows/Foot)
Mod CA Sampler
(Blows/Foot)
Very Soft <2 <3 Very Loose <4 <5
Soft 24 3-6 Loose 4-10 5-12
Firm 5-8 7-12 Medium Dense 11-30 13-35
Stiff 9-15 13-25 Dense 31-50 36-60
Very Stiff 16-30 26-50 Very Dense <50 <60
Hard >30 >50
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BORING NO. B-I
Logged by: SEV Date Drilled: 9/9/2014
Method of Drilling: 8-inch diameter hollow-stem auger Elevation: 260' msl
- I- U. W _I .j -
U. w . uJ
DESCRIPTION LAB TESTS a. uJ 0
w -J Z - 0 m m o
1 FILL: Clayey Sand (SC), brown, fine to medium, moist, medium dense. Expansion Index,
R-Value
2 - (Expansion Index = 36; R-Value = 15)
-
-
20 CAL 119 11.7
.4
.5 -
6 27 CAL -- -- Gravel in sampler.
.7
-8
9 Poorly Graded Sand (SP), light brown, fine, moist, medium dense to dense.
-10
- 30 SRi
- 12
- 13
- 14
----
- 15 -
- 16 30 CAL 113 9.6 Some clay, brown.
- 17
- 18
- 19 Poorly Poorly Graded Sand I Clayey Sand (SP/SC), light brown and brown, fine, moist,
medium dense to dense.
-20 -
-21 30 SRi
22
23
24
----
25 -
26 CAL 110 7.7
27
28
- 29
- PROJECT NO. 1916A10 LOG OF BORING FIGURE B-la
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BORING NO. B-I (continued)
Logged by: SEV Date Drilled: 9/9/2014
Method of Drilling: 8-inch diameter hollow-stem auger Elevation: 260' msl
I- U. Lu _I _i LI. —
LU - Lu
DESCRIPTION LAB TESTS
a. Lu 0
Lu -J z - 0 -J 0 Lu 0
FILL CONTINUED: Clayey Sand (SC), orange, fine, moist, medium dense to
31 dense.
30 SPT
32
33 .
34 - Fat Clay (CH), dark brown, medium plasticity, stiff to very stiff, organic odor.
.35 -
36 30 CAL 113 14.5
37
38
39
40 (LL = 57.4, PL = 16.3, P1 = 41.1) Atterberg Limits -
-41 58 SPT
42 SANTIAGO FORMATION (Tsa): Silty Sandstone' SM', olive gray, fine grain,
moist, moderately cemented.
43
44
.45 -
46 65 SPT Light brown
47
-.--.
48
49
-50 Light brown and orange. -
-51 88 SPT
52 Total depth: 511/2 feet
53 Groundwater not encountered
Backfilled: 9/9/2014
.54
- 55
- 56
- 57
- 58
- 59
-
PROJECT NO. 1916A10 LOG OF BORING FIGURE B-lb
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BORING NO. B-2
Logged by: SEV Date Drilled: 9/10/2014
Method of Drilling: 8-inch diameter hollow-stem auger Elevation: 2621/21 msl
I- U. -
LL
W ..j Ui
a.
LI.
X
LU a.IR . LU
DESCRIPTION LAB TESTS
0 -J D Ui
• FILL: Clayey Sand (SC), brown, fine to medium, dry to moist, medium dense.
2 ------
3 RESIDUAL SOILS: Silty Sand (SM), brown, fine, dry to moist, loose.
Adjacent trench used for identification of cement/sand slurry extent
4 exposed abundant trash which included glass, clothing, aluminum cans,
metal pipes and other debris.
-•---
--
6 69 CAL 115 3.6 OLD PARALIC DEPOSITS, Unit 2-4 Undivided (Q02 ): Silty Sandstone' SM',
orangish brown, fine to medium grain, moist, moderately cemented.
.7
8
.9
10 50-4" SPI
11
12
13
14
15 50-5W SPT
16
-
17
18
50-6° SPT 19 --
20 Total depth: 19 feet
Groundwater not encountered
21 Backfilled: 9/10/2014
22
23
24
25
26
27
28
29
-
PROJECT NO. 1916A10 LOG OF BORING FIGURE B-2
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BORING NO. B-3
Logged by: SEV Date Drilled: 9/9/2014
Method of Drilling: 8-inch diameter hollow-stem auger Elevation: 262 msl
I- U.J .j
U.
Lu w
a.
— LI. —
x
Lu 2 . Lu a.DESCRIPTION LAB TESTS
-J Lu 0 2
- - OLD PARALIC DEPOSITS, Unit 2-4 Undivided (Q02..4): Silty Sandstone' SM', No. 200 Wash, pH,
orangish brown, fine to medium grain, moist, moderately cemented. Resistivity, Sulfate,
2 Chloride
(21.5% Passing No. 200 Sieve)
50-3" CAL
.4
50-3° SPT
-6
.7
-8
-9
- 10 50-5W SPT
- 11
- 12
- 13
- 14
- 15 505h/2 SPT
- 16
- 17
- 18
- 19
- 20 Medium to coarse grain. -
80-11° SPT - - - - 21
- 22 Total depth: 21 feet
Groundwater not encountered
- 23 Backfilled: 9/9/2014
- 24
- 25
26
27
28
29
-
PROJECT NO. 1916A10 LOG OF BORING FIGURE B-3
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BORING NO. B-4
Logged by: SEV Date Drilled: 9/9/2014
Method of Drilling: 8-inch diameter hollow-stem auger Elevation: 259' msl
I-
I— LU
..
LU
U 22 LU
DESCRIPTION LAB TESTS a. LU W > -J 5 z - -J LU 0 2
1 FILL: Sandy Clay (CL), brown, medium plasticity, moist, firm to stiff. Atterberg Limits, pH (LL = 32.2, PL = 14.4, P1 = 17.8; Expansion Index = 57) Resistivity, Sulfate,
- 2 - Chloride, Expansion
- Some asphalt concrete chunks. Index, Maximum
3 20 CAL 109 17.6 Density/Optimum Moisture,
4 Direct Shear
----
6 27 CAL 116 11.0 Clayey Sand / Sandy Clay (SC/CL), brown and yellowish brown, fine, medium plasticity, moist, medium dense, stiff to very stiff.
-7
- 8
-----
Poorly graded sand (SP), light gray and orange, fine, moist, dense, some clay chunks.
.9
-10 -
• 36 SPT
- 12
13 .
. 14 Poorly Graded Sand / Clayey Sand (SP/SC), gray and dark brown, fine, moist, dense.
15 -
16 51 CAL 114 14.8
17
18
19
-.------.----..
-20
21 50 ~SPT Brown and dark brown.
-.
OLD PARALIC DEPOSITS, Unit 2-4 Undivided (Q02.j: Silty Sandstone' SM', 22
23 orangish brown, fine to medium grain, moist, moderately cemented.
24
-25 -
- 26 50-5" CAL 113 7.8
- 27
- 28 Total depth: 31%feet Groundwater not encountered
- 29 Backfilled: 9/9/2014
-30 -
-31 87 SPTI I I I
PROJECT NO. 1916A10 LOG OF BORING FIGURE B-4
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BORING NO. B-5
Logged by: SEV Date Drilled: 9/10/2014
Method of Drilling: 8-inch diameter hollow-stem auger Elevation: 259' msl
— I—
I- LL J LU
a.
w j U. -
LU z LU
DESCRIPTION LAB TESTS
IL
o
W
2 -
5
z - -J LU
1 FILL: Silty Sand (SM), orange and brown, fine to medium, moist, medium dense. Expansion Index,
Maximum Density/
2 - (Expansion Index = 4) Optimum Moisture,
Direct Shear
.3
.4
.5
6 47 cAL. 106 5.3 OLD PARALIC DEPOSITS, Unit 2.4 Undivided (Q02 ): Silty Sandstone' SM', Direct Shear
orangish brown, fine to medium grain, moist, moderately cemented.
.7
8
.9
10 -
11 90-10%" SPT
12
13
14
15 -
16 90-10" SPT
17
18
19
90-10" SPT
20
21 Total depth: 191/2 feet
Groundwater not encountered
22 Backfilled: 9/10/2014
23
24
25
26
27
28
29
-
PROJECT NO. 1916A10 LOG OF BORING FIGURE B-5
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LOG OF EXPLORATION TEST PIT NO. I
Logged by: SEV Date Excavated: 9/9/2014
Equipment Used: 416E backhoe with 18-inch bucket Elevation: 261' msl
w -J I- a.
DESCRIPTION LAB TESTS a. Ui -J o
- 1 FILL: Clayey Sand (SC), brown, fine to coarse, moist, medium dense.
2 Aluminum cans, old clothing, and shoes.
—3
—4
—5
—6
---------------------------------------------------------------------------------------------
-
At 61/2 feet pocket of trash.
Silty Sand (SM), brown, fine to medium, moist, metal debris, organics.
- 8 Total Depth: 10% feet
Groundwater not encountered
- 9 Backfilled: 9/9/2014
- LOG OF EXPLORATION TEST PIT NO. 2
Logged by: SEV Date Excavated: 9/9/2014
Equipment Used: 416E backhoe with 18-inch bucket Elevation: 259' msl
Ui
- I a.
DESCRIPTION LAB TESTS CL Ui -J D
- 1 FILL: Clayey Sand (SC), brown, fine to medium, moist, dense, some gravel.
- 2 Some clay chunks, some gravel.
—3
—4
Pocket of Poorly Graded Sand (SP), light brown, loose.
—6
—7
- 8 Total depth: 9% feet
-
Groundwater not encountered
Backfilled: 9/9/2014
- 10 -
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PROJECT NO. 1916A10 LOG OF TEST PITS FIGURE B-6
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LOG OF EXPLORATION TEST PIT NO. 3
Logged by: SEV Date Excavated: 9/10/2014
Equipment Used: 416E backhoe with 18-inch bucket Elevation: 260' msl
w 1 I- •
DESCRIPTION LAB TESTS a.
Ui _ o
-
Clayey Sand (SC), brown, fine to medium, moist, medium dense to dense.
—2
—3
—4
—5
—6
—7
---------------------------------------------------------------------------------------------
- 8 Silty Sand (SM), light brown, fine to medium, moist, medium dense.
—9
- 10
- 11
- 12
- 13 OLD PARALIC DEPOSITS, Unit 2.4 Undivided (Q02.4): Silty Sandstone' SM',
orangish brown, fine to medium grain, moist, moderately cemented.
- 14 Total depth: 12% feet
E
15 Groundwater not encountered
Backfilled: 9/10/2014
16 -
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PROJECT NO. 1916A10 VA! LOG OF TEST PITS FIGURE B-7
LOG OF EXPLORATION TEST PIT NO. 4
Logged by: SEV Date Excavated: 9/10/2014
Equipment Used: 416E backhoe with 18-inch bucket Elevation: 262' msl
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DESCRIPTION LAB TESTS a. uJ _I o
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FILL: Silty Sand / Sandy Clay (SM/SC), light brown and dark brown, fine to medium, medium
plasticity, moist, medium dense, firm to stiff.
—2
—3
—4
—5
—6
—7
—8
—9
- 10
- 11
- 12
- 13
- 14 Total Depth: 13% feet
- 15 Groundwater not encountered
Backfilled: 9/10/2014
- 16 -
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PROJECT NO. 1916A10 VA! LOG OF TEST PITS FIGURE B-8
LOG OF EXPLORATION TEST PIT NO. 5
Logged by: SEV Date Excavated: 9/10/2014
Equipment Used: 416E backhoe with 18-inch bucket Elevation: 263' msl
LU -j I a.
DESCRIPTION LAB TESTS
IL
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- 1 EJ.hh: Sandy Clay / Clayey Sand (CL/SC), light brown, medium plasticity, fine to medium, moist,
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firm to stiff, medium dense.
—2
—3
Some gravel and cobbles, asphalt concrete debris.
—5
—6
—7
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- 8 - Cement/sand slurry.
Total Depth: 8feet
- Groundwater not encountered
- 10 Backfilled: 9/10/2014
- 11
- 12
- 13
- 14
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PROJECT NO. 1916A10 LOG OF TEST PITS FIGURE B-9
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APPENDIX C
LABORATORY TEST PROCEDURES
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APPENDIX C
LABORATORY TESTING PROCEDURES
Classification
Soils were classified visually, generally according to the Unified Soil Classification
System. Classification tests were also completed on representative samples in accordance
with ASTM D422 for Grain Size. The test resultant soil classifications are shown on the
Boring Logs and Test Pit Logs in Appendix B.
In-Situ Moisture/Density
The in-place moisture content and dry unit weight of selected soil samples were determined
using relatively undisturbed samples from the Cal Tube Sampler. The dry unit weights and
moisture contents are shown on the Boring Logs in Appendix B.
Percent Passing No. 200 Sieve
Particle size determinations for the percentage of sample passing the No. 200 sieve were
performed in general accordance with the laboratory procedures outlined in ASTM test
Method D1140. The results are shown on the Boring Logs in Appendix B.
Atterberg Limits
The liquid limit, plastic limit, and plasticity index of selected soil samples were estimated in
general accordance with the laboratory procedures outlined in ASTM D 4318. The results
are shown on Figure C- 1.
Maximum Density
Maximum density tests were performed on a representative bag sample of the near surface
soils in accordance with ASTM D1557. Test results are presented below.
Sample Description Maximum Dry Optimum Moisture
Location Density (pci) Content (%)
B-4 at 0 to 2' Sandy Clay (CL) - Brown 125.6 9.4
B-5 at 0 to 2' Silty Sand (SM) - Orange and Brown 133.1 9.5
Page C-1
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Lot 9 and CMWD Water Tank Site - Geotechnical Investigation MTGL Project No. 1916A10
Carlsbad, California MTGL Log No. 14-1168
Direct Shear
Direct Shear Tests were performed on in-place samples of site soils in accordance with
ASTM D3080. The test results are presented in Figures C-2 thru C-4.
Expansion Index
Expansion Index testing was completed in accordance with the standard test method ASTM
D4829. Test results are presented below.
Sample
Location Description Expansion Index
(El)
Expansion
Index
B-i at 0 to 2' Clayey Sand - Brown 36 Low
B-4 at 0 to 2' Sandy Clay (CL) - Brown 57 Medium
B-5 at 0 to 2' Silty Sand (SM) - Orange and Brown 4 Very Low
Corrosion
Chemical testing was performed on representative samples to determine the corrosion
potential of the onsite soils. Testing consisted of pH, chlorides (CTM 422), soluble sulfates
(CTM 417), and resistivity (CTM 643). Test results are as follows:
Sample p H Chlorides Sulfates Resistivity
Location (ppm) (ppm) (ohm-cm
B-3at1'to3' 7.6 148 111 3,600
B-4at0to2' 8.5 544 247 690
R-Value
R-value test was performed on a sample of the upper soils in general accordance with the
laboratory procedures outlined in ASTM D 2844. Test results are presented below.
Sample I Description R-Value Location
B-i at 0 to 2' —F—
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Clayey Sand (SC) - Brown 15
Page C-2
VA
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LIQUID AND PLASTIC LIMITS TEST REPORT
60
50
40
w
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30 0
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10
0 10 20 30 40 50 60 70 80 90 100 110
LIQUID LIMIT
MTGL, Inc. Client:
Project: MARBRISA RESORTS - LOT 9
San Diegp, CA Project No.: 1916-AIO Figure c-I
Tested By: JH Checked By:SV
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Dashed line indicates the approximate /
upper limit boundary for natural soils
/ / / /
/ / /
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ML or OL MH or OH
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SOIL DATA
NATURAL
SAMPLE DEPTH SOURCE USCS WATER PLASTIC LIQUID
NO. CONTENT LIMIT LIMIT
f1I 40
(%)(%)(%)
BI 16.3 57.4
• B4 0-2' 14.4 32.2 17.8
3000
2000
Sample No. 1 2 3
Water Content, % 9.4 9.4 9.5
Dry Density, pcf 119.9 119.9 119.8
Saturation, % 65.6 65.6 66.0
£ Void Ratio 0.3794 0.3794 0.3804
Diameter, in. 2.42 2.42 2.42
Height, in. 1.00 1.00 1.00
Water Content, % 13.7 13.5 13.8
2
- Dry Density, pcf 121.1 121.8 121,1
Saturation, % 99.6 99.5 99.4
Void Ratio 0.3656 0.35 87 0.3666
Diameter, in. 2.42 2.42 2.42
- Height, in. 0.99 0.98 0.99
Normal Stress, psf 1000 2000 4000
Fail. Stress, psf 1005 1656 2855
Strain, % 3.3 2.4 7.0
Ult. Stress, psf 745 1290 2533
Strain, % 13.1 12.3 11.7
Strain rate, in./min. 0.01 0.01 0.01
Client:
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$1• IRRUUUUUUNWU• .aio..uiii a .4aRaPauu..I.•wuuaa
no moss NOME
11. Ill. Bua
.uivaia
uaaaaua•uauuauaauaaa
u.am.aaaaa
aaiwmu•auaauaupuauuaauu.auiLOU MMMMMMMMMMMM aaiuuu.a•aumaa
ME 0 aaaau..•uuuau MEMIMMMIMMMILUJILLIE MEMEMEM
IIIIId a....a.aaurn..u....aau.
_____ •uuuaaaauu•..uaaivaumuauuiuulalla .....uuaardaa.uuuauaa
..s.uaaaua..so uaa HILI MEN ER NUNN DREMEME p.saaauaaauaisauaaamauaauumIuuuu•.
104 j.uua.uuma au.uauu..uaaua.u.a...au..uuuuumauIumaauuaaalaUIU a.. a asusa
I 1000 2000 :jsltl. 4000 5000 601II0
Normal Stress, psi
Strain, %
Sample Type:
I Description:
Project: MARBRISA RESORTS - LOT 9
Specific Gravity= 2.65 Sample Number: B5 Depth: 0-2
Remarks:
Proj. No.: 1916-AIO Date Sampled:
DIRECT SHEAR TEST REPORT
MTGL, Inc.
Figure C-3
Normal Stress, psf
0 10 20 30 40
Strain, %
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Specific Gravity= 2.65
I Remarks:
Sample Type:
Description:
Figure C-4
Sample No. 1 2 3
Water Content, % 5.4 5.0 5.4
Dry Density, pcf 105.9 106.1 104.9
Saturation, % 25.5 23.9 24.8
Void Ratio 0.5617 0.5599 0.5772
Diameter, in. 2.42 2.42 2.42
- Height, in. 1.00 1.00 1.00
Water Content, % 20.4 20.1 21.0
Dry Density, pcf 107.3 107.7 106.0
Saturation % 99.9 99.5 99.2
2 Void Ratio 0.5414 0.5365 0.5614
Diameter, in. 2.42 2.42 2.42
- Height, in. 0.99 0.98 0.99
Normal Stress, psf 1000 2000 4000
Fail, Stress, psf 1187 1929 3403
Strain, % 8.5 7.2 5.4
Ult. Stress, psf 842 3184
Strain,% 22.3 17.4
Strain rate, in/mm. 0.01 0.01 0.01
Client:
Project: MARBRISA RESORTS - LOT 9
Sample Number: B5 Depth: 5
Proj. No.: 1916-AIO Date Sampled:
DIRECT SHEAR TEST REPORT
MTGL, Inc.
San Diego, CA
Lot 9 and CMWD Water Tank Site - Geotechnical Investigation MTGL Project No. 1916A10
Carlsbad, California MTGL Log No. 14-1168
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I APPENDIX D
I STANDARD GRADING SPECIFICATIONS
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Lot 9 and CMWD Water Tank Site - Geotechnical Investigation MTGL Project No. 1916A10
Carlsbad, California MTGL Log No. 14-1168
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APPENDIX D
GENERAL EARTHWORK AND GRADING SPECIFICATIONS
I GENERAL
1 These specifications present general procedures and requirements for grading and earthwork as
shown on the approved grading plans, including preparation of areas to be filled, placement of fill,
I installation of subdrams, and excavations. The recommendations contained in the attached
geotechnical report are a part of the earthwork and grading specifications and shall supersede the
provisions contained herein in the case of conflict. Evaluations performed by the Consultant I during the course of grading may result in new recommendations, which could supersede these
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specifications, or the recommendations of the geotechnical report.
EARTHWORK OBSERVATION AND TESTING
I Prior to the start of grading, a qualified Geotechnical Consultant (Geotechnical Engineer) shall be
employed for the purpose of observing earthwork procedures and testing the fills for conformance
I with the recommendations of the geotechnical report and these specifications. It will be necessary
that the Consultant provide adequate testing and observation so that he may determine that the
I work was accomplished as specified. It shall be the responsibility of the Contractor to assist the
Consultant and keep them apprised of work schedules and changes so that he may schedule his
personnel accordingly.
It shall be the sole responsibility of the Contractor to provide adequate equipment and methods to
I accomplish the work in accordance with applicable grading codes or agency ordinances, these
specifications and the approved grading plans.
I Maximum dry density tests used to determine the degree of compaction will be performed in
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accordance with the American Society for Testing and Materials Test Method (ASTM) D15 57.
PREPARATION OF AREAS TO BE FILLED
I Clearing and Grubbing: All brush, vegetation and debris shall be removed or piled and otherwise
disposed of.
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Lot 9 and CMWD Water Tank Site - Geotechnical Investigation MTGL Project No. 1916A10
Carlsbad, California MTGL Log No. 14-1168
Processing: The existing ground which is determined to be satisfactory for support of fill shall be
scarified to a minimum depth of 12 inches. Existing ground, which is not satisfactory, shall be
overexcavated as specified in the following section.
Overexcavation: Soft, dry, spongy, highly fractured or otherwise unsuitable ground, extending to
such a depth that surface processing cannot adequately improve the condition, shall be
overexcavated down to firm ground, approved by the Consultant.
Moisture conditioning: Overexcavated and processed soils shall be watered, dried-back, blended,
and mixed as required to have a relatively uniform moisture content near the optimum moisture
content as determined by ASTM D1557.
Recompaction: Overexcavated and processed soils, which have been mixed, and moisture
conditioned uniformly shall be recompacted to a minimum relative compaction of 90 percent of
ASTM D1557.
Benching: Where soils are placed on ground with slopes steeper than 5:1 (horizontal to vertical),
the ground shall be stepped or benched. Benches shall be excavated in firm material for a
minimum width of 4 feet.
FILL MATERIAL
General: Material to be placed as fill shall be free of organic matter and other deleterious
substances, and shall be approved by the Consultant.
Oversize: Oversized material defined as rock, or other irreducible material with a maximum
dimension greater than 12 inches, shall not be buried or placed in fill, unless the location, material,
and disposal methods are specifically approved by the Consultant. Oversize disposal operations
shall be such that nesting of oversized material does not occur, and such that the oversize material
is completely surrounded by compacted or densified fill. Oversize material shall not be placed
within 10 feet vertically of finish grade or within the range of future utilities or underground
construction, unless specifically approved by the Consultant.
Import: If importing of fill material is required for grading, the import material shall meet the
general requirements.
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Lot 9 and CMWD Water Tank Site - Geotechnical Investigation MTGL Project No. 1916A10
Carlsbad, California MTGL Log No. 14-1168
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I FILL PLACEMENT AND COMPACTION
Fill Lifts: Approved fill material shall be placed in areas prepared to receive fill in near-horizontal
layers not exceeding 6 inches in compacted thickness. The Consultant may approve thicker lifts if
testing indicates the grading procedures are such that adequate compaction is being achieved with
I lifts of greater thickness. Each layer shall be spread evenly and shall be thoroughly mixed during
spreading to attain uniformity of material and moisture in each layer.
Fill Moisture: Fill layers at a moisture content less than optimum shall be watered and mixed, and
wet fill layers shall be aerated by scarification or shall be blended with drier material. Moisture
conditioning and mixing of fill layers shall continue until the fill material is at uniform moisture
content at or near optimum.
I Compaction of Fill: After each layer has been evenly spread, moisture conditioned, and mixed, it
shall be uniformly compacted to not less that 90 percent of maximum dry density in accordance
I with ASTM D1557. Compaction equipment shall be adequately sized and shall be either
specifically designed for soil compaction or of proven reliability, to efficiently achieve the
specified degree of compaction.
Fill Slopes: Compacting on slopes shall be accomplished, in addition to normal compacting
procedures, by backrolling of slopes with sheepsfoot rollers at frequent increments of 2 to 3 feet as
the fill is placed, or by other methods producing satisfactory results. At the completion of grading,
the relative compaction of the slope out to the slope face shall be at least 90 percent in accordance
with ASTM D1557.
Compaction Testing: Field tests to check the fill moisture and degree of compaction will be
performed by the consultant. The location and frequency of tests shall be at the consultant's
discretion. In general, these tests will be taking at an interval not exceeding 2 feet in vertical rise,
and/or 1,000 cubic yards of fill placed. In addition, on slope faces, at least one test shall be taken
for each 5,000 square feet of slope face and/or each 10 feet of vertical height of slope.
SUBDRA1N INSTALLATION
Subdrain systems, if required, shall be installed in approved ground to conform to the approximate
alignment and details shown on the plans or herein. The subdrain location or materials shall not be
changed or modified without the approval of the Consultant. The Consultant, however, may
recommend and, upon approval, direct changes in subdrain line, grade or materials. All subdrains
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Carlsbad, California MTGL Log No. 14-1168
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should be surveyed for line and grade after installation and sufficient time shall be allowed for the
I surveys, prior to commencement of fill over the subdrain.
EXCAVATION
Excavations and cut slopes will be examined during grading. If directed by the Consultant, further
excavation or overexcavation and refilling of cut areas, and/or remedial grading of cut slopes shall
be performed. Where fill over cut slopes are to be graded, unless otherwise approved, the cut
portion of the slope shall be made and approved by the Consultant prior to placement of materials
for construction of the fill portion of the slope.
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