HomeMy WebLinkAboutPD 2021-0042; 2940 CACATUA ADU; LIMITED GEOTECHNICAL EVALUATION; 2022-03-04
LIMITED GEOTECHNICAL Evaluation
PROPOSED AUXILIARY DWELLING UNIT (ADU)
2940 CACATUA STREET
CARLSBAD, CALIFORNIA
PREPARED FOR
Kris Alberts
2940 Cacatua Street
CARLSBAD, CALIFORNIA 92069
PREPARED BY
GEOTEK, INC.
1384 POINSETTIA AVENUE, SUITE A
VISTA, CALIFORNIA 92081
PROJECT NO. 3766-SD MARCH 4, 2022
GEOTEK
GEOTECHNICAL | ENVIRONMENTAL | MATERIALS
March 4, 2022
Project No. 3766-SD
Kris Alberts
2940 Cacatua Street
Carlsbad, California
Subject: Limited Geotechnical Evaluation
Proposed Auxiliary Dwelling Unit (ADU)
2940 Cacatua
Carlsbad, California
Dear Mr. Alberts:
GeoTek, Inc. (GeoTek) is pleased to provide results of this Limited Geotechnical
Evaluation for the subject project. This report presents the results of GeoTek’s limited
evaluation and provides preliminary geotechnical recommendations for foundation
design and construction. Based upon review, site development appears feasible from a
geotechnical viewpoint provided that the recommendations included herein are incorporated
into the design and construction phases of site development. The opportunity to be of service
is sincerely appreciated. If you should have any questions, please do not hesitate to contact
GeoTek.
Respectfully submitted,
GeoTek, Inc.
Christopher D. Livesey Bruce A. Hick
CEG 2733 GE 2284
Associate Vice President Geotechnical Engineer
Distribution: (1) Addressee via email
GeoTek, Inc.
1384 Poinsettia Avenue, Suite A Vista, CA 92081-8505
(760) 599-0509 Office (760) 599-0593 Fa, www.geotekusa.com
GEOTECHNICAL I ENVIROI
KRIS ALBERTS Project No. 3766-SD
Limited Geotechnical Evaluation March 4, 2022
2940 Cacatua, Carlsbad, California Page i
TABLE OF CONTENTS
PURPOSE AND SCOPE OF SERVICES............................................................................................................ 1
SITE DESCRIPTION AND PROPOSED DEVELOPMENT ........................................................................... 1
1.1 Site Description ................................................................................................................................ 1
1.2 Proposed Development ..................................................................................................................... 1
FIELD EXPLORATION AND LABORATORY TESTING ............................................................................. 2
1.3 Field Exploration ............................................................................................................................... 2
1.4 Laboratory Testing ............................................................................................................................ 2
GEOLOGIC AND SOILS CONDITIONS .......................................................................................................... 2
1.5 Regional Setting ................................................................................................................................ 2
1.6 EARTH MATERIALS ......................................................................................................................... 3
1.6.1 Artificial Fill (Af) ................................................................................................................................ 3
1.7 SURFACE WATER AND GROUNDWATER ........................................................................................ 3
1.7.1 Surface Water .................................................................................................................................. 3
1.7.2 Groundwater .................................................................................................................................... 3
1.8 EARTHQUAKE HAZARDS ................................................................................................................ 4
1.8.1 Surface Fault Rupture ....................................................................................................................... 4
1.8.2 Liquefaction/Seismic Settlement......................................................................................................... 4
1.8.3 Other Seismic Hazards ..................................................................................................................... 4
CONCLUSIONS AND RECOMMENDATIONS ............................................................................................... 5
1.9 GENERAL ........................................................................................................................................ 5
1.10 EARTHWORK CONSIDERATIONS ................................................................................................... 5
1.10.1 General ....................................................................................................................................... 5
1.10.2 Site Clearing and Preparation ....................................................................................................... 5
1.10.3 Engineered Fill ............................................................................................................................. 5
1.10.4 Excavation Characteristics ............................................................................................................ 6
1.10.5 Shrinkage and Bulking ................................................................................................................. 6
1.11 DESIGN RECOMMENDATIONS ....................................................................................................... 6
1.11.1 Foundation Design Criteria ........................................................................................................... 6
1.11.2 Foundation Setbacks .................................................................................................................... 7
1.11.3 Miscellaneous Foundation Recommendations ................................................................................ 7
1.11.4 Underslab Moisture Membrane ................................................................................................... 8
1.11.5 Seismic Design Parameters .......................................................................................................... 9
1.11.6 Soil Sulfate Content ................................................................................................................... 10
2. RETAINING WALL DESIGN AND CONSTRUCTION .................................................................................... 10
2.1.1 General Design Criteria ................................................................................................................... 10
2.1.2 Cantilevered Walls .......................................................................................................................... 10
2.1.3 Restrained Retaining Walls ............................................................................................................. 11
2.1.4 Seismic Induced Equivalent Fluid Pressures ...................................................................................... 11
2.1.5 Retaining Wall Backfill and Drainage............................................................................................... 11
2.2 POST CONSTRUCTION CONSIDERATIONS ................................................................................... 12
2.2.1 Landscape Maintenance and Planting .............................................................................................. 12
2.2.2 Drainage ........................................................................................................................................ 13
2.3 PLAN REVIEW AND CONSTRUCTION OBSERVATIONS ................................................................. 13
LIMITATIONS .................................................................................................................................................... 14
SELECTED REFERENCES .............................................................................................................................. 15
GEOTEK
KRIS ALBERTS Project No. 3766-SD
Limited Geotechnical Evaluation March 4, 2022
2940 Cacatua, Carlsbad, California Page ii
TABLE OF CONTENTS
ENCLOSURES
Figure 1 – Site Location Map
Figure 2 – Geotechnical Map
Appendix A – Logs of Exploration
Appendix B – Results of Laboratory Testing
Appendix C – General Grading Guidelines
GEOTEK
KRIS ALBERTS Project No. 3731-SD
Limited Geotechnical Evaluation March 4, 2022
2940 Cacatua, Carlsbad, California Page 1
PURPOSE AND SCOPE OF SERVICES
The purpose of this study was to evaluate the geotechnical conditions on the project site.
Services provided for this study included the following:
Research and review of available geologic and geotechnical data, and general information
pertinent to the site.
A site reconnaissance.
Advancement of two (2) manual auger explorations and collection of relatively
undisturbed and loose bulk soil samples for subsequent laboratory testing.
Laboratory testing of the soil samples collected during the field investigation.
Compilation of this geotechnical report which presents findings of pertinent site
geotechnical conditions and geotechnical recommendations for site development.
SITE DESCRIPTION AND PROPOSED DEVELOPMENT
1.1 Site Description
The subject project site is located within the northeast portion of the property at 2940 Cacatua,
Carlsbad, San Diego County, California. The property is surrounded by residential homes within
a tract subdivision. Current property improvements consist of a primary single-family residence,
a driveway, a swimming pool, and landscaping. Small (less than 20 feet) manufactured slopes
descend into the property. The proposed improvements described herein and the area outlined
on Figure 2, are referred to as the “site.”
1.2 Proposed Development
Based on the Minor Grading Plan prepared by Latitude 33 Planning & Engineering, the proposed
project will consist of an auxiliary dwelling unit (ADU) northeast of the primary residence. The
650 square foot, single story, ADU will be recessed into an ascending hillside with an
approximate gradient of 2:1 (horizontal : vertical). The height of the retained earth is 6.5 feet.
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KRIS ALBERTS Project No. 3731-SD
Limited Geotechnical Evaluation March 4, 2022
2940 Cacatua, Carlsbad, California Page 2
As site planning progresses and additional or revised plans become available, the plans should be
provided to GeoTek for review and comment. Additional geotechnical field exploration,
laboratory testing and engineering analyses may be necessary to provide specific earthwork
recommendations and geotechnical design parameters for site development.
FIELD EXPLORATION AND LABORATORY TESTING
1.3 Field Exploration
The field exploration for this evaluation was conducted on January 20th, 2022, and included a site
reconnaissance, excavation of two (2) exploratory manual auger borings, and collection of
relatively undisturbed and bulk soil samples for laboratory testing. A representative from
GeoTek visually logged the soil cuttings. The approximate location of the explorations are
presented on the Geotechnical Map, Figure 2. Descriptions of materials encountered in the
borings are presented in the Logs of Exploration presented in Appendix A.
1.4 Laboratory Testing
Laboratory testing was performed on representative soil samples collected during the field
exploration. The purpose of the laboratory testing was to evaluate the physical and chemical soil
properties for use in engineering design and analysis. Results of the laboratory testing program,
along with a brief description and relevant information regarding testing procedures, are included
in Appendix B.
GEOLOGIC AND SOILS CONDITIONS
1.5 Regional Setting
The subject property is located in the Peninsular Ranges geomorphic province. The Peninsular
Ranges province is one of the largest geomorphic units in western North America. Generally, it
extends roughly 975 miles from the north and northeasterly adjacent the Transverse Ranges
geomorphic province to the tip of Baja California. This province varies in width from about 30
to 100 miles. It is bounded on the west by the Pacific Ocean, on the south by the Gulf of
California and on the east by the Colorado Desert Province.
GEOTEK
KRIS ALBERTS Project No. 3731-SD
Limited Geotechnical Evaluation March 4, 2022
2940 Cacatua, Carlsbad, California Page 3
The Peninsular Ranges are essentially a series of northwest-southeast oriented fault blocks.
Several major fault zones are found in this province. The Elsinore Fault zone and the San Jacinto
Fault zones trend northwest-southeast and are found in the near the middle of the province. The
San Andreas Fault zone borders the northeasterly margin of the province. The Newport-
Inglewood-Rose Canyon Fault zone borders the southwest margin of the province. No faults are
shown in the immediate site vicinity on the map reviewed for the area.
1.6 EARTH MATERIALS
A brief description of the earth materials encountered during the subsurface exploration is
presented in the following sections. Based on field observations and review of published geologic
maps the subject site is locally underlain by artificial fill over Tertiary-age Santiago Formation.
The as-graded geotechnical report, prepared by Benton Engineering for the subdivision was
reviewed. The report noted the project lot to be a “cut” lot. GeoTek’s explorations
encountered fill soils at the surface, but encountered practical refusal at each location by no
advancement of the auger. The practical refusal is interpreted to be the fill bedrock contact.
1.6.1 Artificial Fill (Af)
Artificial fill soils were encountered in both explorations to the maximum depths explored (2
feet). The fill consisted of silty fine to medium sand (SM soil type based upon the Unified Soil
Classification System), tan brown in color, moist, and compact.
1.7 SURFACE WATER AND GROUNDWATER
1.7.1 Surface Water
Surface water was not observed during the site visit. If encountered, surface water on this site
will most likely be the result of flow from the pool in the rear yard, precipitation or possibly
some minor surface run-off from immediately surrounding grades. Provisions for surface drainage
should be addressed by the project design civil engineer.
1.7.2 Groundwater
Groundwater or perched water was not encountered in the explorations and is not anticipated
to be a factor in site development. Localized perched groundwater could be present but is also
not anticipated to be a significant factor in site development.
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KRIS ALBERTS Project No. 3731-SD
Limited Geotechnical Evaluation March 4, 2022
2940 Cacatua, Carlsbad, California Page 4
1.8 EARTHQUAKE HAZARDS
1.8.1 Surface Fault Rupture
The geologic structure of the entire southern California area is dominated mainly by northwest-
trending faults associated with the San Andreas system. The site is in a seismically active region.
No active or potentially active fault is known to exist at this site nor is the site situated within an
“Alquist-Priolo” Earthquake Fault Zone or a Special Studies Zone (Bryant and Hart, 2007). The
nearest potentially active fault zone is the Newport-Inglewood-Rose Canyon fault zone which is
located approximately 10 miles west of the site.
1.8.2 Liquefaction/Seismic Settlement
Liquefaction describes a phenomenon in which cyclic stresses, produced by earthquake-induced
ground motion, create excess pore pressures in relatively cohesionless soils. These soils may
thereby acquire a high degree of mobility, which can lead to lateral movement, sliding,
consolidation and settlement of loose sediments, sand boils and other damaging deformations.
This phenomenon occurs only below the water table, but, after liquefaction has developed, the
effects can propagate upward into overlying non-saturated soil as excess pore water dissipates.
The factors known to influence liquefaction potential include soil type and grain size, relative
density, groundwater level, confining pressures, and both intensity and duration of ground
shaking. In general, materials that are susceptible to liquefaction are loose, saturated granular
soils having low fines content under low confining pressures.
The liquefaction potential and seismic settlement potential on this site are considered negligible,
due to the generally dense nature of the near surface Santiago Formation and lack of shallow
groundwater.
1.8.3 Other Seismic Hazards
Evidence of ancient landslides or slope instabilities at this site was not observed during this study
or indicated on regional geologic maps. The potential for landslides is considered negligible.
The potential for secondary seismic hazards such as seiche and tsunami is considered to be
remote due to site elevation and distance from an open body of water, as confirmed by the
ASCE Tsunami Hazard Tool.
GEOTEK
KRIS ALBERTS Project No. 3731-SD
Limited Geotechnical Evaluation March 4, 2022
2940 Cacatua, Carlsbad, California Page 5
CONCLUSIONS AND RECOMMENDATIONS
1.9 GENERAL
Development of the site appears feasible from a geotechnical viewpoint provided that the
following recommendations are incorporated in the design and construction phases of the
development. The following sections present general recommendations for currently anticipated
site development plans.
Recommendations contained herein are based on the currently applicable 2019 California
Building Code (CBC).
1.10 EARTHWORK CONSIDERATIONS
1.10.1 General
Earthwork and grading should be performed in accordance with the applicable grading ordinances
of the City of Carlsbad, the 2019 (or current) CBC, and recommendations contained in this
report. The Grading Guidelines included in Appendix C outline general procedures and do not
anticipate all site-specific situations. In the event of conflict, the recommendations presented in
the text of this report should supersede those contained in Appendix C.
1.10.2 Site Clearing and Preparation
Site preparation should start with removal of vegetation and debris. These materials should be
disposed properly off site. Any existing underground improvements (utilities) should also be
removed, rerouted as appropriate, or be further evaluated as part of site development
operations. If fill is needed to return stripped grades to pad grades, engineered fill should be
placed in accordance to section 1.10.3 – Engineered Fill. Prior to placement of engineered fills
the removal bottom surface should be processed by scarification and moisture conditioning to 1-
2% above optimum moisture content and compacted to a minimum of 90% relative compaction
as determined by ASTM D 1557 test procedures.
1.10.3 Engineered Fill
Onsite materials are generally considered suitable for reuse as engineered fill provided they are
free from vegetation, roots, debris, and rock/concrete or hard lumps greater than six (6) inches
in maximum dimension.
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Acceptable engineered fill materials, if needed, should be placed in horizontal lifts not exceeding
8 inches in loose thickness, moisture conditioned to at or slightly above the optimum moisture
content and compacted to a minimum relative compaction of 90% per ASTM D 1557 test
procedures.
1.10.4 Excavation Characteristics
Excavations in the onsite artificial fill should generally be accomplished with medium to heavy-
duty earthmoving or excavating equipment in good operating condition.
1.10.5 Shrinkage and Bulking
Due to the limited extent of currently proposed work, effects of shrinking and bulking are
anticipated to be minimal.
1.11 DESIGN RECOMMENDATIONS
1.11.1 Foundation Design Criteria
For shallow foundations, design criteria presented herein are for foundations that will bear
entirely upon competent fill material or Santiago Formation and are in general conformance with
the 2019 CBC. Below are geotechnical recommendations for foundation design, all structural
design shall be performed by the project structural engineer.
Based on visual classification of materials encountered onsite and as verified by laboratory testing,
soils near the anticipated building subgrade have a “ very low” expansion index (EI<20) per ASTM
D4829.
MINIMUM DESIGN REQUIREMENTS FOR CONVENTIONALLY REINFORCED
FOUNDATIONS SUPPORTED ON ENGINEERED FILL
DESIGN PARAMETER “Very Low”
Expansion Potential (51≤EI≤89)
Foundation Embedment Depth or Minimum Perimeter
Beam Depth (inches below lowest adjacent finished
grade)
18 inches
Minimum Foundation Width (Inches) 12 inches
Minimum Slab Thickness (actual) 4 Inches
Minimum Slab Reinforcing No. 3 rebar 16” on-center, each way, placed in the
middle one-third of the slab thickness
Minimum Footing Reinforcement No. 4 rebar two on top and two on bottom
Pre-saturation of Subgrade Soil (percent of optimum
moisture content) Minimum 100% to a depth of 12 inches
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The following recommendations should be implemented into the design:
An allowable bearing capacity of 2,000 pounds per square foot (psf) may be used for
design of continuous and perimeter footings that meet the depth and width
requirements in the table above. This value may be increased by 400 pounds per
square foot for each additional 12 inches in depth and 200 pounds per square foot
for each additional 12 inches in width to a maximum value of 3,000 psf. Additionally,
an increase of one-third may be applied when considering short-term live loads (e.g.
seismic and wind loads).
Based on experience in the area, structural foundations may be designed in
accordance with 2019 CBC, and to withstand a total settlement of 1 inch and
maximum differential settlement of one-half of the total settlement over a horizontal
distance of 40 feet. These values assume that seismic settlement potential is not a
significant constraint.
The passive earth pressure may be computed as an equivalent fluid having a density
of 250 psf per foot of depth, to a maximum earth pressure of 2,500 psf for footings
founded on engineered fill. A coefficient of friction between soil and concrete of 0.30
may be used with dead load forces. When combining passive pressure and frictional
resistance, the passive pressure component should be reduced by one-third.
1.11.2 Foundation Setbacks
Where applicable, the following setbacks should apply to all foundations. Any improvements not
conforming to these setbacks may be subject to lateral movements and/or differential
settlements:
The bottom of all footings for structures near retaining walls should be deepened to
extend below a 1:1 projection upward from the bottom inside edge of the wall stem.
This applies to the existing retaining walls along the perimeter if they are to remain.
The bottom of any existing foundations for structures should be deepened to extend
below a 1:1 projection upward from the bottom of the nearest excavation.
1.11.3 Miscellaneous Foundation Recommendations
To reduce the effects of slope creep impacting shallow foundations, the foundations
associated with the shallow perimeter or interior footings should extend to a
minimum depth of 6 feet below lowest adjacent finish grade or to a depth that results
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KRIS ALBERTS Project No. 3731-SD
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in a horizontal distance of at least 12 feet from the bottom outside edge of the pier
to the face of descending slope, whichever is greater.
To reduce moisture penetration beneath the slab on grade areas, utility trenches
should be backfilled with engineered fill, lean concrete or concrete slurry where they
intercept the perimeter footing or thickened slab edge.
Spoils from the footing excavations should not be placed in the slab-on-grade areas
unless properly compacted and tested. The excavations should be free of
loose/sloughed materials and be neatly trimmed at the time of concrete placement.
1.11.4 Underslab Moisture Membrane
A moisture and vapor retarding system should be placed below slabs-on-grade where moisture
migration through the slab is undesirable. Guidelines for these are provided in the 2016 California
Green Building Standards Code (CALGreen) Section 4.505.2 and the 2019 CBC Section 1907.1
It should be realized that the effectiveness of the vapor retarding membrane can be adversely
impacted as a result of construction related punctures (e.g. stake penetrations, tears, punctures
from walking on the vapor retarder placed atop the underlying aggregate layer, etc.). These
occurrences should be limited as much as possible during construction. Thicker membranes are
generally more resistant to accidental puncture that thinner ones. Products specifically designed
for use as moisture/vapor retarders may also be more puncture resistant. Although the CBC
specifies a 6 mil vapor retarder membrane, it is GeoTek’s opinion that a minimum 10 mil
membrane with joints properly overlapped and sealed should be considered, unless otherwise
specified by the slab design professional.
Moisture and vapor retarding systems are intended to provide a certain level of resistance to
vapor and moisture transmission through the concrete, but do not eliminate it. The acceptable
level of moisture transmission through the slab is to a large extent based on the type of flooring
used and environmental conditions. Ultimately, the vapor retarding system should be comprised
of suitable elements to limit migration of water and reduce transmission of water vapor through
the slab to acceptable levels. The selected elements should have suitable properties (i.e.
thickness, composition, strength and permeability) to achieve the desired performance level.
Moisture retarders can reduce, but not eliminate, moisture vapor rise from the underlying soils
up through the slab. Moisture retarder systems should be designed and constructed in
accordance with applicable American Concrete Institute, Portland Cement Association, Post-
Tensioning Concrete Institute, ASTM and California Building Code requirements and guidelines.
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KRIS ALBERTS Project No. 3731-SD
Limited Geotechnical Evaluation March 4, 2022
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GeoTek does not practice in the field of moisture vapor transmission evaluation/migration since
that practice is not a geotechnical discipline. Therefore, it is recommended that a qualified
person, such as the flooring contractor, structural engineer, architect, and/or other experts
specializing in moisture control within the building be consulted to evaluate the general and
specific moisture and vapor transmission paths and associated potential impact on the proposed
construction. That person (or persons) should provide recommendations relative to the slab
moisture and vapor retarder systems and for migration of potential adverse impact of moisture
vapor transmission on various components of the structures, as deemed appropriate. In addition,
the recommendations in this report and GeoTek’s services in general are not intended to address
mold prevention; since GeoTek, along with geotechnical consultants in general, do not practice
in the area of mold prevention. If specific recommendations addressing potential mold issues are
desired, then a professional mold prevention consultant should be contacted.
1.11.5 Seismic Design Parameters
The site is located at approximately 33.1132 Latitude and -117.2388 Longitude. Site spectral
accelerations (Ss and S1), for 0.2 and 1.0 second periods for a risk targeted two (2) percent
probability of exceedance in 50 years (MCER) were determined using the web interface provided
by SEAOC/OSHPD (https://seismicmaps.org) to access the USGS Seismic Design Parameters. A
Site Class “C” is deemed appropriate for this site based on the apparent density of the shallow
bedrock below the surface. The results are presented in the following table.
SITE SEISMIC PARAMETERS
Mapped 0.2 sec Period Spectral Acceleration, Ss 0.933g
Mapped 1.0 sec Period Spectral Acceleration, S1 0.342g
Site Coefficient for Site Class “C”, Fa 1.2
Site Coefficient for Site Class “C”, Fv 1.5
Maximum Considered Earthquake (MCER) Spectral
Response Acceleration for 0.2 Second, SMS 1.12g
Maximum Considered Earthquake (MCER) Spectral
Response Acceleration for 1.0 Second, SM1 0.513g
5% Damped Design Spectral Response
Acceleration Parameter at 0.2 Second, SDS 0.747g
5% Damped Design Spectral Response
Acceleration Parameter at 1 second, SD1 0.342g
Peak Ground Acceleration (PGAM) 0.487g
Seismic Design Category D
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1.11.6 Soil Sulfate Content
The sulfate content was determined in the laboratory for a soil sample collected during the field
investigation. The results indicate that the water soluble sulfate is less than 0.1 percent by weight,
which is considered “S0” or “negligible” per Table 19.3.1.1 of ACI 318-14. Based upon the test
results, no special recommendations for concrete are required for this project due to soil sulfate
exposure.
2. RETAINING WALL DESIGN AND CONSTRUCTION
2.1.1 General Design Criteria
Recommendations presented herein may apply to typical masonry or concrete vertical retaining
walls to a maximum height of up to 10 feet. Additional review and recommendations should be
requested for higher walls. The retaining wall designer should decide if the basement wall is a
restrained wall or an active wall with an allowable deflection of 0.001H at the top of the wall.
Retaining wall foundations at least 12 inches wide embedded a minimum of 18 inches into
engineered fill deposits should be designed using an allowable bearing capacity of 2,000 pounds
per square foot (psf) may be used for design of continuous and perimeter footings that meet the
depth and width requirements in the table above. This value may be increased by 400 pounds
per square foot for each additional 12 inches in depth and 200 pounds per square foot for each
additional 12 inches in width to a maximum value of 3,000 psf. Additionally, an increase of one-
third may be applied when considering short-term live loads (e.g. seismic and wind loads).
The passive earth pressure may be computed as an equivalent fluid having a density of 250 psf
per foot of depth, to a maximum earth pressure of 2,500 psf for footings founded on engineered
fill. A coefficient of friction between soil and concrete of 0.30 may be used with dead load forces.
passive pressure and frictional resistance can be combined without reduction.
Retaining walls, should consider the use of a waterproofing to reduce moisture transmission
through the wall facing elements and resulting efflorescence.
2.1.2 Cantilevered Walls
The recommendations presented below are for cantilevered retaining walls up to 10 feet high.
Active earth pressure may be used for retaining wall design, provided the top of the wall is not
restrained from minor deflections. An equivalent fluid pressure approach may be used to compute
the horizontal pressure against the wall. Appropriate fluid unit weights are given below for
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specific slope gradients of the retained material. These do not include other superimposed loading
conditions such as traffic, structures, seismic events, or adverse geologic conditions.
ACTIVE EARTH PRESSURES
Surface Slope of
Retained Materials (h:v)
Equivalent Fluid Pressure(pcf)
Granular Materials*
Level Does Not Apply
2:1 65
*Select imported granular fill with an expansion index less than 20. Backfill zone
includes area between back of wall to plane (1:1, h:v) up from back of wall
foundation to ground surface.
2.1.3 Restrained Retaining Walls
Any retaining walls that will be restrained (e.g. basement walls) prior to placing and compacting
backfill material or that have reentrant or male corners, should be designed for an at-rest
equivalent fluid pressure of 90 pcf for level backfill, plus any applicable surcharge loading. For
areas of male or reentrant corners, the restrained wall design should extend a minimum distance
of twice the height of the wall laterally from the corner.
2.1.4 Seismic Induced Equivalent Fluid Pressures
It should be noted that the 2019 CBC requires the inclusion of an additional earthquake-induced
lateral force to be considered on retaining walls retaining more than 6 feet of soil. An
incremental seismic (dynamic) lateral earth pressure of 25 pcf is recommended for cantilever
(unrestrained) walls with sloping backfill (up to a maximum slope of 2:1 (h:v). The point of
application of the dynamic load increment is at 2/3H and above, where H is the retained height.
Additional surcharge loads from adjacent structures, pavements, retaining walls, etc. should be
incorporated by the structural engineer into the retaining wall design as necessary.
2.1.5 Retaining Wall Backfill and Drainage
Retaining and/or basement wall backfill should consist of very low expansive soil (EI<20), be free
of deleterious and/or oversized materials. The wall backfill should also include a minimum one-
foot-wide section of ¾- to 1-inch clean crushed rock (or approved equivalent). The rock should
be placed immediately adjacent to the back of wall and extend up from the back drain to within
approximately 12 inches of finish grade. The upper 12 inches should consist of compacted onsite
materials. Presence of other materials might necessitate revision to the parameters provided and
modification of wall designs. The backfill materials should be placed in lifts no greater than 8-
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inches in thickness and compacted to a minimum of 90 percent of the soil’s maximum dry density
as determined by ASTM D 1557 test procedures. Proper surface drainage needs to be provided
and maintained. Bracing of the walls during backfilling and compaction may also be necessary.
All earth retention structures should be provided with an adequate pipe and gravel back drain
system to reduce the potential for hydrostatic pressure build up. As a minimum, backdrains
should consist of a four-inch diameter perforated collector pipe (Schedule 40, SDR 35, or
approved equivalent) embedded in a minimum of one cubic foot per lineal foot of ¾- to 1-inch
clean crushed rock or equivalent, wrapped in filter fabric (Mirafi 140N or approved equivalent).
The drain system should be connected to a suitable outlet, as determined by the civil
engineer. Drain outlets should be maintained over the life of the project and should not be
obstructed or plugged by adjacent improvements. Waterproofing of site walls should be
performed where moisture migration through the wall is undesirable.
As an alternative to the drain, rock and fabric, a pre-manufactured wall drainage product
(example: Mira Drain 6000 or approved equivalent) may be used behind the retaining wall. The
wall drainage product should extend from the base of the wall to within two (2) feet of the
ground surface. The subdrain should be placed in direct contact with the wall drainage product.
Proper surface drainage needs to be provided and maintained. Water should not be allowed to
pond behind retaining walls. Waterproofing of site walls should be performed where moisture
migration through the wall is undesirable.
2.2 POST CONSTRUCTION CONSIDERATIONS
2.2.1 Landscape Maintenance and Planting
Water has been shown to weaken the inherent strength of soil, and slope stability is significantly
reduced by overly wet conditions. Positive surface drainage away from graded slopes should be
maintained and only the amount of irrigation necessary to sustain plant life should be provided
for planted slopes. Controlling surface drainage and runoff and maintaining a suitable vegetation
cover can limit erosion. Plants selected for landscaping should be lightweight, deep-rooted types
that require little water and can survive the prevailing climate.
Overwatering should be avoided. Care should be taken when adding soil amendments to avoid
excessive watering. Leaching as a method of soil preparation prior to planting is not
recommended. An abatement program to control ground-burrowing rodents should be
implemented and maintained. This is critical as burrowing rodents can decreased the long-term
performance of slopes.
GEOTEK
KRIS ALBERTS Project No. 3731-SD
Limited Geotechnical Evaluation March 4, 2022
2940 Cacatua, Carlsbad, California Page 13
It is common for planting to be placed adjacent to structures in planter or lawn areas. This will
result in the introduction of water into the ground adjacent to the foundation. This type of
landscaping should be avoided. If used, then extreme care should be exercised with regard to
the irrigation and drainage in these areas. Waterproofing of the foundation and/or subdrains
may be warranted and advisable. GeoTek could discuss these issues, if desired, when plans are
made available.
2.2.2 Drainage
The need to maintain proper surface drainage and subsurface systems cannot be overly emphasized.
Positive site drainage should be always maintained. Drainage should not flow uncontrolled down
any descending slope. Water should be directed away from foundations and not allowed to pond
or seep into the ground adjacent to the footings. Site drainage should conform to Section 1804.4
of the 2019 CBC. Roof gutters and downspouts should discharge onto paved surfaces sloping away
from the structure or into a closed pipe system which outfalls to the street gutter pan or directly
to the storm drain system. Pad drainage should be directed toward approved areas and not be
blocked by other improvements.
It is the owner’s responsibility to maintain and clean drainage devices on or contiguous to their
lot. In order to be effective, maintenance should be conducted on a regular and routine schedule
and necessary corrections made prior to each rainy season.
2.3 PLAN REVIEW AND CONSTRUCTION OBSERVATIONS
It is recommended that changes to site grading, specifications, and any retaining wall/shoring
plans and foundation plans be reviewed by this office prior to construction to check for
conformance with the recommendations of this report. Additional recommendations may be
necessary based on these reviews. It is also recommended that GeoTek representatives be
present during site grading and foundation construction to check for proper implementation of
the geotechnical recommendations. The owner/developer should have GeoTek’s representative
perform at least the following duties:
Observe site clearing and grubbing operations for proper removal of unsuitable materials.
Observe the fill for uniformity during placement including utility trenches.
Observe and test the fill for field density and relative compaction.
Observe and probe foundation excavations to confirm suitability of bearing materials.
Observe and test materials for concrete placement.
GEOTEK
KRIS ALBERTS Project No. 3731-SD
Limited Geotechnical Evaluation March 4, 2022
2940 Cacatua, Carlsbad, California Page 14
If requested, a construction observation and compaction report can be provided by GeoTek,
which can comply with the requirements of the governmental agencies having jurisdiction over
the project. It is recommended that these agencies be notified prior to commencement of
construction so that necessary grading permits can be obtained.
LIMITATIONS
The scope of this evaluation is limited to the area explored that is shown on the Geotechnical
Map (Figure 2). This evaluation does not and should in no way be construed to encompass any
areas beyond the specific area of proposed construction as indicated to us by the client. Further,
no evaluation of any existing site improvements is included. The scope of services for this report
is based on GeoTek’s understanding of the project and the client’s needs, GeoTek’s proposal
(Proposal No. P-0100622-SD) dated January 19th, 2022, and geotechnical engineering standards
normally used on similar projects in this region.
The materials observed on the project site appear to be representative of the area; however,
soil and bedrock materials vary in character between excavations and natural outcrops, or
conditions exposed during site construction. Site conditions may vary due to seasonal changes
or other factors. GeoTek, Inc. assumes no responsibility or liability for work, testing or
recommendations performed or provided by others.
Since the recommendations contained in this report are based on the site conditions observed
and encountered, and laboratory testing, the conclusions and recommendations are professional
opinions that are limited to the extent of the available data. Observations during construction
are important to allow for any change in recommendations found to be warranted. These
opinions have been derived in accordance with current standards of practice and no warranty is
expressed or implied. Standards of practice are subject to change with time.
GEOTEK
KRIS ALBERTS Project No. 3731-SD
Limited Geotechnical Evaluation March 4, 2022
2940 Cacatua, Carlsbad, California Page 15
SELECTED REFERENCES
American Society of Civil Engineers (ASCE), 2016, “Minimum Design Loads for Buildings and
Other Structures,” ASCE/SEI 7-16.
_____, ASCE Tsunami Hazard Tool, 2018, ASCE Tsunami Design Geodatabase Version 2016-
1.0, updated March 3, 2018, accessed February 5, 2019 at https://asce7tusnami.online/
ASTM International (ASTM), “ASTM Volumes 4.08 and 4.09 Soil and Rock.”
Bryant, W.A., and Hart, E.W., 2007, "Fault Rupture Hazard Zones in California, Alquist-Priolo
Earthquake Fault Zoning Act with Index to Earthquake Fault Zones Maps," California
Geological Survey: Special Publication 42.
California Code of Regulations, Title 24, 2019 “California Building Code,” 2 volumes.
California Geological Survey (CGS, formerly referred to as the California Division of Mines and
Geology), 1977, “Geologic Map of California.”
____, 1998, “Maps of Known Active Fault Near-Source Zones in California and Adjacent
Portions of Nevada,” International Conference of Building Officials.
GeoTek, Inc., In-house proprietary information.
Kennedy, M.P., and Tan, S.S., 2007, “Geologic Map of the Oceanside 30x60-minute Quadrangle,
California,” California Geological Survey, Regional Geologic Map No. 2, map scale
1:100,000.
Structural Engineers Association of California/California Office of Statewide Health Planning and
Development (SEOC/OSHPD), 2021, Seismic Design Maps web interface, accessed
October 27, 2021 at https://seismicmaps.org
GEOTEK
Kris Alberts
2940 Cacatua St
Carlsbad, California
1384 Poinsettia Avenue, Suite A
Vista, California 92081
Figure 1
Site Location
N
Not to Scale
Imagery from US Forestry Service, 2022
Approximate Site
Location
PN: 3766-SD DATE: March 2022
GEOTEK
HA-1HA-2Af1384 Poinsettia Avenue, Suite AVista, California 92081PN: 3766-SDDATE: March 2022Figure 2Geotechnical MapKris Alberts2940 Cacatua StCarlsbad, CaliforniaNot to ScaleImagery from Google Earth, 2022NApproximate Location ofBoringHA-2LEGENDApproximate Limits ofStudy, this reportAfArtificial Fill♦ GEOTEK
KRIS ALBERTS Project No. 3731-SD
Limited Geotechnical Evaluation March 4, 2022
2940 Cacatua, Carlsbad, California Page 16
APPENDIX A
LOGS OF EXPLORATION
GEOTEK
Page A-1
A - FIELD TESTING AND SAMPLING PROCEDURES
Bulk Samples (Large)
These samples are normally large bags of earth materials over 20 pounds in weight collected from the
field by means of hand digging or exploratory cuttings.
Bulk Samples (Small)
These are plastic bag samples which are normally airtight and contain less than 5 pounds in weight of
earth materials collected from the field by means of hand digging or exploratory cuttings. These samples
are primarily used for determining natural moisture content and classification indices.
B – EXPLORATORY LOG LEGEND
The following abbreviations and symbols often appear in the classification and description of soil and rock
on the logs of borings:
SOILS
USCS Unified Soil Classification System
f-c Fine to coarse
f-m Fine to medium
GEOLOGIC
B: Attitudes Bedding: strike/dip
J: Attitudes Joint: strike/dip
C: Contact line
……….. Dashed line denotes USCS material change
Solid Line denotes unit / formational change
Thick solid line denotes end of the boring
(Additional denotations and symbols are provided on the log of Explorations)
GEOTEK
GeoTek, Inc.
LOG OF EXPLORATORY BORING
R-1
---Small Bulk ---No Recovery ---Water Table
RV = R-Value Test
SR = Sulfate/Resisitivity Test SH = Shear Test CO = Consolidation test MD = Maximum Density
30
LEGENDSample type: ---Ring ---SPT ---Large Bulk
Lab testing:AL = Atterberg Limits EI = Expansion Index SA = Sieve Analysis
25
20
15
10
HOLE TERMINATED AT 2 FEET
No groundwater encountered
5 Practical refusal at 2 feet
Backfilled with adjacent soil
Silty fine to medium SAND, light brown, moist, dense
Silty fine to medium SAND, light brown, damp, large fragments of rock
No advancement of auger, practical refusal Dry Density (pcf)Others MATERIAL DESCRIPTION AND COMMENTS
Fill
SAMPLES
USCS Symbol BORING NO.: HA-1
Laboratory Testing
Depth (ft)Sample TypeBlows/ 6 inSample NumberWater Content (%)LOCATION:Carlsbad, CA ELEVATION:510 ft DATE:1/20/2022
PROJECT NO.:3766-SD HAMMER:Slide Hammer RIG TYPE:Manual Auger
PROJECT NAME:2940 Cacatua St.DRILL METHOD:Boring OPERATOR:MRF
CLIENT:Kris Alberts DRILLER:GeoTek, Inc LOGGED BY:MRF
---------------------------------------------------------------• I 0 [g] □ ~
GeoTek, Inc.
LOG OF EXPLORATORY BORING
BB-1 SM
R-1
---Small Bulk ---No Recovery ---Water Table
AL = Atterberg Limits EI = Expansion Index SA = Sieve Analysis RV = R-Value Test
SR = Sulfate/Resisitivity Test SH = Shear Test CO = Consolidation test MD = Maximum Density
30
LEGENDSample type: ---Ring ---SPT ---Large Bulk
Lab testing:
25
20
15
10
Backfilled with adjacent soil
HOLE TERMINATED AT 2 FEET
5 No groundwater encountered
Practical refusalt at 2 feet
Silty fine to medium SAND, light brown, moist, dense
Silty fine to medium SAND, light brown, damp, loose, some large rock fragments
More rock fragments
No advancement of auger, practical refusal Dry Density (pcf)Others MATERIAL DESCRIPTION AND COMMENTS
Fill
SAMPLES
USCS Symbol BORING NO.: HA-2
Laboratory Testing
Depth (ft)Sample TypeBlows/ 6 inSample NumberWater Content (%)LOCATION:Carlsbad, CA ELEVATION:DATE:1/20/2022
PROJECT NO.:3766-SD HAMMER:Slide Hammer RIG TYPE:Manual Auger
PROJECT NAME:2940 Cacatua St.DRILL METHOD:Boring OPERATOR:MRF
CLIENT:Kris Alberts DRILLER:GeoTek, Inc LOGGED BY:MRF
------=~ -,___ -
-------------------------------------------------------• I 0 [g] □ ~
APPENDIX B
RESULTS OF LABORATORY TESTING
GEOTEK
KRIS ALBERTS Project No. 3766-SD
Limited Geotechnical Evaluation March 4, 2022
2940 Cacatua, Carlsbad, California Page B-1
SUMMARY OF LABORATORY TESTING
Identification and Classification
Soils were identified visually in general accordance with the standard practice for description and
identification of soils (ASTM D2488). The soil identifications and classifications are shown on the logs of
exploratory borings in Appendix A of this report.
Moisture-Density Relationship
Laboratory testing was performed on one (1) soil sample collected during the subsurface exploration.
The laboratory maximum dry density and optimum moisture content were determined in general
accordance with ASTM D 1557 test procedures. The results of the tests are presented in Appendix B.
Expansion Index
Expansion Index testing was performed on a representative soil sample. Testing was performed in general
accordance with ASTM Test Method D 4829. The result of the testing is presented in Appendix B.
Sulfate Content
The sulfate content was determined by GeoTek’s subconsultant, Project X, in general accordance with
ASTM D 4327. The results of the testing are provided in Appendix B.
GEOTEK
Tested/ Checked By:
Date Tested:
Sample Source:
Sample Description:
Ring Id:Ring Dia. " :Ring Ht.":
A Weight of compacted sample & ring
B Weight of ring
C Net weight of sample
D
E
Wet Weight of sample & tare
Dry Weight of sample & tare
Tare
F Initial Moisture Content, %
G (E*F)
H (E/167.232)
I (1.-H)
J (62.4*I)
K (G/J)= L % Saturation
EXPANSION INDEX =
EXPANSION INDEX TEST
(ASTM D4829)
10
Tare
4.8
FINAL MOISTURE
%
Moisture
Weight of wet
sample & tare
Wt. of dry
sample & tare
159.1
1"
180.4
179.2
4.9
162.5
SATURATION DETERMINATION
22.8
10.6
49.4
9:34
370.5
DENSITY DETERMINATION
Wet Density, lb / ft3 (C*0.3016)
0.36
0.64
106.2
1125.5
389.5
117.5
Random
9:23 139
132
9:33
Initial
137
1 min/Wet
10 min/Dry
3/4/2022
760
4"12
1309:39
Dry Density, lb / ft3 (D/1.F)
Project Number:
Project Name:2940 Cacatua
3766-SD
Project Location:
CH
Carlsbad, California
Loading weight: 5516. grams
HA-1 and HA-2
3/5/2022
Tan Brown Silty Sand
Lab No
3/5/0200 9:23 149
TIME READINGDATE
Final
3693
13.8%
5 min/Wet
READINGS
GEOTEK
--I
I I
MOISTURE/DENSITY RELATIONSHIP
Client:Kris Alberts Job No.:3766-SD
Project:2940 Cacatua St.Lab No.:3657
Location:Carlsbad, CA
Material Type:Tan-Light Brown Sitly Sand w/ some rocks
Material Supplier:-
Material Source:-
Sample Location:2940 Cacatua St.
-
Sampled By:MF Date Sampled:3/3/2022
Received By:MRB Date Received:3/3/2022
Tested By:MRB Date Tested:3/4/2022
Reviewed By:-Date Reviewed:-
Test Procedure:ASTM D1557 Method:A
Oversized Material (%):0.0 Correction Required: yes x no
MOISTURE CONTENT (%):5.141129 8.579466 9.753231 12.26415 5.141129 8.579466 9.7532315 12.26415
DRY DENSITY (pcf):111.7531 115.5615 120.1465 121.0212
CORRECTED DRY DENSITY (pcf):#DIV/0! #DIV/0! #DIV/0! #DIV/0!
ZERO AIR VOIDS DRY DENSITY (pcf):
MOISTURE DENSITY RELATIONSHIP VALUES
Maximum Dry Density, pcf 123.0 @ Optimum Moisture, %11.0
Corrected Maximum Dry Density, pcf @ Optimum Moisture, %
MATERIAL DESCRIPTION
Grain Size Distribution:Atterberg Limits:
% Gravel (retained on No. 4)Liquid Limit, %
% Sand (Passing No. 4, Retained on No. 200)Plastic Limit, %
% Silt and Clay (Passing No. 200)Plasticity Index, %
Classification:
Unified Soils Classification:
AASHTO Soils Classification:
106
108
110
112
114
116
118
120
122
124
126
6 7 8 9 10 11 12 13 14 15 16 17DRY DENSITY, PCFMOISTURE CONTENT, %
MOISTURE/DENSITY RELATIONSHIP CURVE DRY DENSITY (pcf):
CORRECTED DRY DENSITY (pcf):
ZERO AIR VOIDS DRY DENSITY (pcf)
S.G. 2.7
S.G. 2.8
S.G. 2.6
Poly. (DRY DENSITY (pcf):)
OVERSIZE CORRECTED
ZERO AIR VOIDS
Poly. (S.G. 2.7)
Poly. (S.G. 2.8)
Poly. (S.G. 2.6)
GEOTEK
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Project X REPORT S220304A
Corrosion Engineering Page 1
Corrosion Control – Soil, Water, Metallurgy Testing Lab
29990 Technology Dr, Suite 13, Murrieta, CA 92563 Tel: 213-928-7213 Fax: 951-226-1720
www.projectxcorrosion.com
Results Only Soil Testing
for
2940 Cacatua St
March 4, 2022
Prepared for:
Chris Livesey
GeoTek, Inc.
1384 Poinsettia Ave, Suite A
Vista, CA, 92081
clivesey@geotekusa.com
Project X Job#: S220304A
Client Job or PO#: 3766-SD
Respectfully Submitted,
Eduardo Hernandez, M.Sc., P.E.
Sr. Corrosion Consultant
NACE Corrosion Technologist #16592
Professional Engineer
California No. M37102
ehernandez@projectxcorrosion.com
Project X REPORT S220304A
Corrosion Engineering Page 2
Corrosion Control – Soil, Water, Metallurgy Testing Lab
29990 Technology Dr., Suite 13, Murrieta, CA 92563 Tel: 213-928-7213 Fax: 951-226-1720
www.projectxcorrosion.com
Soil Analysis Lab Results
Client: GeoTek, Inc.
Job Name: 2940 Cacatua St
Client Job Number: 3766-SD
Project X Job Number: S220304A
March 4, 2022
Method
Bore# / Description Depth
(ft)(mg/kg)(wt%)
BB-1 Tan Silty Sand 0-2 149.3 0.0149
ASTM
D4327
Sulfates
SO42-
Cations and Anions, except Sulfide and Bicarbonate, tested with Ion Chromatography
mg/kg = milligrams per kilogram (parts per million) of dry soil weight
ND = 0 = Not Detected | NT = Not Tested | Unk = Unknown
Chemical Analysis performed on 1:3 Soil-To-Water extract
PPM = mg/kg (soil) = mg/L (Liquid)
Lab Rtqucn Shttt Chaia of Custody
Phone: l213)928-7213 · l'a,q9Sl)n6-1720 -www.projccncamosion.com
Ship Samples To: 29990 Technology Dr, Suite 13, Murrieta, CA 92563
Project X .Job Number 2.CJ4o CACA,TU4
IMPORTANT: Pltart tomplol1' Projtd aod Samplt ldcatinalion Data a., you wollfd Uke it to appear la report & lndudttllls l'orna witb samplu.
CompaayNumc,: GeoTek, Inc.
MaillngAdtlrn:,: 1384 Poinsetta Ave, Ste A, Vista, CA 92081
Ac<oantiai:Contact: Accounts Pa able
Client Proj«1 No: :S f-fc, lo -~ "9
P.O. II: \) 1 s I t:,..
Rmilts By: 0 Phono O .,,., [a Email
Datt & Rc«btd by :
SrN'ill lnstnuU.es:
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11-ltlllod
Coatoct Namt: Chris Livesey Pbonc No: 949-338-9233
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Cl') < Cl') ~ (J 10
APPENDIX C
GENERAL GRADING GUIDELINES
GENERAL GRADING GUIDELINES APPENDIX C
Page C- 1
GENERAL GRADING GUIDELINES
Guidelines presented herein are intended to address general construction procedures for earthwork
construction. Specific situations and conditions often arise which cannot reasonably be discussed in
general guidelines, when anticipated these are discussed in the text of the report. Often
unanticipated conditions are encountered which may necessitate modification or changes to these
guidelines. It is our hope that these will assist the contractor to more efficiently complete the
project by providing a reasonable understanding of the procedures that would be expected during
earthwork and the testing and observation used to evaluate those procedures.
General
Grading should be performed to at least the minimum requirements of governing agencies, the
California Building Code, CBC (2019) and the guidelines presented below.
Preconstruction Meeting
A preconstruction meeting should be held prior to site earthwork. Any questions the contractor has
regarding our recommendations, general site conditions, apparent discrepancies between reported
and actual conditions and/or differences in procedures the contractor intends to use should be
brought up at that meeting. The contractor (including the main onsite representative) should review
our report and these guidelines in advance of the meeting. Any comments the contractor may have
regarding these guidelines should be brought up at that meeting.
Grading Observation and Testing
1. Observation of the fill placement should be provided by our representative during grading.
Verbal communication during the course of each day will be used to inform the contractor of
test results. The contractor should receive a copy of the "Daily Field Report" indicating
results of field density tests that day. If our representative does not provide the contractor
with these reports, our office should be notified.
2. Testing and observation procedures are, by their nature, specific to the work or area
observed and location of the tests taken, variability may occur in other locations. The
contractor is responsible for the uniformity of the grading operations; our observations and
test results are intended to evaluate the contractor’s overall level of efforts during grading.
The contractor’s personnel are the only individuals participating in all aspect of site work.
Compaction testing and observation should not be considered as relieving the contractor’s
responsibility to properly compact the fill.
3. Cleanouts, processed ground to receive fill, key excavations, and subdrains should be
observed by our representative prior to placing any fill. It will be the contractor's
responsibility to notify our representative or office when such areas are ready for
observation.
4. Density tests may be made on the surface material to receive fill, as considered warranted by
this firm.
5. In general, density tests would be made at maximum intervals of two feet of fill height or
every 1,000 cubic yards of fill placed. Criteria will vary depending on soil conditions and size
of the fill. More frequent testing may be performed. In any case, an adequate number of
field density tests should be made to evaluate the required compaction and moisture content
is generally being obtained.
GENERAL GRADING GUIDELINES APPENDIX C
Page C- 2
6. Laboratory testing to support field test procedures will be performed, as considered
warranted, based on conditions encountered (e.g. change of material sources, types, etc.)
Every effort will be made to process samples in the laboratory as quickly as possible and in
progress construction projects are our first priority. However, laboratory workloads may
cause in delays and some soils may require a minimum of 48 to 72 hours to complete
test procedures. Whenever possible, our representative(s) should be informed in advance
of operational changes that might result in different source areas for materials.
7. Procedures for testing of fill slopes are as follows:
a) Density tests should be taken periodically during grading on the flat surface of the fill,
three to five feet horizontally from the face of the slope.
b) If a method other than over building and cutting back to the compacted core is to be
employed, slope compaction testing during construction should include testing the
outer six inches to three feet in the slope face to determine if the required
compaction is being achieved.
8. Finish grade testing of slopes and pad surfaces should be performed after construction is
complete.
Site Clearing
1. All vegetation, and other deleterious materials, should be removed from the site. If material
is not immediately removed from the site it should be stockpiled in a designated area(s) well
outside of all current work areas and delineated with flagging or other means. Site clearing
should be performed in advance of any grading in a specific area.
2. Efforts should be made by the contractor to remove all organic or other deleterious material
from the fill, as even the most diligent efforts may result in the incorporation of some
materials. This is especially important when grading is occurring near the natural grade. All
equipment operators should be aware of these efforts. Laborers may be required as root
pickers.
3. Nonorganic debris or concrete may be placed in deeper fill areas provided the procedures
used are observed and found acceptable by our representative. Typical procedures are
similar to those indicated on Plate G-4.
Treatment of Existing Ground
1. Following site clearing, all surficial deposits of alluvium and colluvium as well as weathered or
creep effected bedrock, should be removed (see Plates G-1, G-2 and G-3) unless otherwise
specifically indicated in the text of this report.
2. In some cases, removal may be recommended to a specified depth (e.g. flat sites where
partial alluvial removals may be sufficient). The contractor should not exceed these depths
unless directed otherwise by our representative.
3. Groundwater existing in alluvial areas may make excavation difficult. Deeper removals than
indicated in the text of the report may be necessary due to saturation during winter months.
4. Subsequent to removals, the natural ground should be processed to a depth of six inches,
moistened to near optimum moisture conditions and compacted to fill standards.
5. Exploratory back hoe or dozer trenches still remaining after site removal should be
excavated and filled with compacted fill if they can be located.
GENERAL GRADING GUIDELINES APPENDIX C
Page C- 3
Subdrainage
1. Subdrainage systems should be provided in canyon bottoms prior to placing fill, and behind
buttress and stabilization fills and in other areas indicated in the report. Subdrains should
conform to schematic diagrams G-1 and G-5, and be acceptable to our representative.
2. For canyon subdrains, runs less than 500 feet may use six-inch pipe. Typically, runs in excess
of 500 feet should have the lower end as eight-inch minimum.
3. Filter material should be clean, 1/2 to 1-inch gravel wrapped in a suitable filter fabric. Class 2
permeable filter material per California Department of Transportation Standards tested by
this office to verify its suitability, may be used without filter fabric. A sample of the material
should be provided to the Soils Engineer by the contractor at least two working days before
it is delivered to the site. The filter should be clean with a wide range of sizes.
4. Approximate delineation of anticipated subdrain locations may be offered at 40-scale plan
review stage. During grading, this office would evaluate the necessity of placing additional
drains.
5. All subdrainage systems should be observed by our representative during construction and
prior to covering with compacted fill.
6. Subdrains should outlet into storm drains where possible. Outlets should be located and
protected. The need for backflow preventers should be assessed during construction.
7. Consideration should be given to having subdrains located by the project surveyors.
Fill Placement
1. Unless otherwise indicated, all site soil and bedrock may be reused for compacted fill;
however, some special processing or handling may be required (see text of report).
2. Material used in the compacting process should be evenly spread, moisture conditioned,
processed, and compacted in thin lifts six (6) to eight (8) inches in compacted thickness to
obtain a uniformly dense layer. The fill should be placed and compacted on a nearly
horizontal plane, unless otherwise found acceptable by our representative.
3. If the moisture content or relative density varies from that recommended by this firm, the
contractor should rework the fill until it is in accordance with the following:
a) Moisture content of the fill should be at or above optimum moisture. Moisture
should be evenly distributed without wet and dry pockets. Pre-watering of cut or
removal areas should be considered in addition to watering during fill placement,
particularly in clay or dry surficial soils. The ability of the contractor to obtain the
proper moisture content will control production rates.
b) Each six-inch layer should be compacted to at least 90 percent of the maximum dry
density in compliance with the testing method specified by the controlling
governmental agency. In most cases, the testing method is ASTM Test Designation
D 1557.
4. Rock fragments less than eight inches in diameter may be utilized in the fill, provided:
a) They are not placed in concentrated pockets;
b) There is a sufficient percentage of fine-grained material to surround the rocks;
c) The distribution of the rocks is observed by, and acceptable to, our representative.
5. Rocks exceeding eight (8) inches in diameter should be taken off site, broken into smaller
fragments, or placed in accordance with recommendations of this firm in areas designated
suitable for rock disposal (see Plate G-4). On projects where significant large quantities of
oversized materials are anticipated, alternate guidelines for placement may be included. If
GENERAL GRADING GUIDELINES APPENDIX C
Page C- 4
significant oversize materials are encountered during construction, these guidelines should be
requested.
6. In clay soil, dry or large chunks or blocks are common. If in excess of eight (8) inches
minimum dimension, then they are considered as oversized. Sheepsfoot compactors or
other suitable methods should be used to break up blocks. When dry, they should be
moisture conditioned to provide a uniform condition with the surrounding fill.
Slope Construction
1. The contractor should obtain a minimum relative compaction of 90 percent out to the
finished slope face of fill slopes. This may be achieved by either overbuilding the slope and
cutting back to the compacted core, or by direct compaction of the slope face with suitable
equipment.
2. Slopes trimmed to the compacted core should be overbuilt by at least three (3) feet with
compaction efforts out to the edge of the false slope. Failure to properly compact the outer
edge results in trimming not exposing the compacted core and additional compaction after
trimming may be necessary.
3. If fill slopes are built "at grade" using direct compaction methods, then the slope construction
should be performed so that a constant gradient is maintained throughout construction. Soil
should not be "spilled" over the slope face nor should slopes be "pushed out" to obtain
grades. Compaction equipment should compact each lift along the immediate top of slope.
Slopes should be back rolled or otherwise compacted at approximately every 4 feet vertically
as the slope is built.
4. Corners and bends in slopes should have special attention during construction as these are
the most difficult areas to obtain proper compaction.
5. Cut slopes should be cut to the finished surface. Excessive undercutting and smoothing of
the face with fill may necessitate stabilization.
Keyways, Buttress and Stabilization Fills
Keyways are needed to provide support for fill slope and various corrective procedures.
1. Side-hill fills should have an equipment-width key at their toe excavated through all surficial
soil and into competent material and tilted back into the hill (Plates G-2, G-3). As the fill is
elevated, it should be benched through surficial soil and slopewash, and into competent
bedrock or other material deemed suitable by our representatives (See Plates G-1, G-2, and
G-3).
2. Fill over cut slopes should be constructed in the following manner:
a) All surficial soils and weathered rock materials should be removed at the cut-fill
interface.
b) A key at least one and one-half (1.5) equipment width wide (or as needed for
compaction), and tipped at least one (1) foot into slope, should be excavated into
competent materials and observed by our representative.
c) The cut portion of the slope should be excavated prior to fill placement to evaluate if
stabilization is necessary. The contractor should be responsible for any additional
earthwork created by placing fill prior to cut excavation. (see Plate G-3 for
schematic details.)
3. Daylight cut lots above descending natural slopes may require removal and replacement of
the outer portion of the lot. A schematic diagram for this condition is presented on Plate G-
2.
GENERAL GRADING GUIDELINES APPENDIX C
Page C- 5
4. A basal key is needed for fill slopes extending over natural slopes. A schematic diagram for
this condition is presented on Plate G-2.
5. All fill slopes should be provided with a key unless within the body of a larger overall fill
mass. Please refer to Plate G-3 for specific guidelines.
Anticipated buttress and stabilization fills are discussed in the text of the report. The need to
stabilize other proposed cut slopes will be evaluated during construction. Plate G-5 shows a
schematic of buttress construction.
1. All backcuts should be excavated at gradients of 1:1 or flatter. The backcut configuration
should be determined based on the design, exposed conditions, and need to maintain a
minimum fill width and provide working room for the equipment.
2. On longer slopes, backcuts and keyways should be excavated in maximum 250 feet long
segments. The specific configurations will be determined during construction.
3. All keys should be a minimum of two (2) feet deep at the toe and slope toward the heel at
least one foot or two (2%) percent, whichever is greater.
4. Subdrains are to be placed for all stabilization slopes exceeding 10 feet in height. Lower
slopes are subject to review. Drains may be required. Guidelines for subdrains are
presented on Plate G-5.
5. Benching of backcuts during fill placement is required.
Lot Capping
1. When practical, the upper three (3) feet of material placed below finish grade should be
comprised of the least expansive material available. Preferably, highly and very highly
expansive materials should not be used. We will attempt to offer advice based on visual
evaluations of the materials during grading, but it must be realized that laboratory testing is
needed to evaluate the expansive potential of soil. Minimally, this testing takes two (2) to
four (4) days to complete.
2. Transition lots (cut and fill) both per plan and those created by remedial grading (e.g. lots
above stabilization fills, along daylight lines, above natural slopes, etc.) should be capped with
a minimum three foot thick compacted fill blanket.
3. Cut pads should be observed by our representative(s) to evaluate the need for
overexcavation and replacement with fill. This may be necessary to reduce water infiltration
into highly fractured bedrock or other permeable zones, and/or due to differing expansive
potential of materials beneath a structure. The overexcavation should be at least three feet.
Deeper overexcavation may be recommended in some cases.
ROCK PLACEMENT AND ROCK FILL GUIDELINES
If large quantities of oversize material would be generated during grading, it’s likely that such
materials may require special handling for burial. Although alternatives may be developed in the field,
the following methods of rock disposal are recommended on a preliminary basis.
Limited Larger Rock
When materials encountered are principally soil with limited quantities of larger rock fragments or
boulders, placement in windrows is recommended. The following procedures should be applied:
1. Oversize rock (greater than 8 inches) should be placed in windrows.
a) Windrows are rows of single file rocks placed to avoid nesting or clusters of rock.
GENERAL GRADING GUIDELINES APPENDIX C
Page C- 6
b) Each adjacent rock should be approximately the same size (within ~one foot in
diameter).
c) The maximum rock size allowed in windrows is four feet
2. A minimum vertical distance of three feet between lifts should be maintained. Also, the
windrows should be offset from lift to lift. Rock windrows should not be closer than 15 feet
to the face of fill slopes and sufficient space must be maintained for proper slope
construction (see Plate G-4).
3. Rocks greater than eight inches in diameter should not be placed within seven feet of the
finished subgrade for a roadway or pads and should be held below the depth of the lowest
utility. This will allow easier trenching for utility lines.
4. Rocks greater than four feet in diameter should be broken down, if possible, or they may be
placed in a dozer trench. Each trench should be excavated into the compacted fill a
minimum of one foot deeper than the largest diameter of rock.
a) The rock should be placed in the trench and granular fill materials (SE>30) should be
flooded into the trench to fill voids around the rock.
b) The over size rock trenches should be no closer together than 15 feet from any
slope face.
c) Trenches at higher elevation should be staggered and there should be a minimum of
four feet of compacted fill between the top of the one trench and the bottom of the
next higher trench.
d) It would be necessary to verify 90 percent relative compaction in these pits. A 24 to
72 hour delay to allow for water dissipation should be anticipated prior to additional
fill placement.
Structural Rock Fills
If the materials generated for placement in structural fills contains a significant percentage of material
more than six (6) inches in one dimension, then placement using conventional soil fill methods with
isolated windrows would not be feasible. In such cases the following could be considered:
1. Mixes of large rock or boulders may be placed as rock fill. They should be below the depth
of all utilities both on pads and in roadways and below any proposed swimming pools or
other excavations. If these fills are placed within seven (7) feet of finished grade, they may
affect foundation design.
2. Rock fills are required to be placed in horizontal layers that should not exceed two feet in
thickness, or the maximum rock size present, which ever is less. All rocks
exceeding two feet should be broken down to a smaller size, windrowed (see above), or
disposed of in non-structural fill areas. Localized larger rock up to 3 feet in largest dimension
may be placed in rock fill as follows:
a) individual rocks are placed in a given lift so as to be roughly 50% exposed above the
typical surface of the fill ,
b) loaded rock trucks or alternate compactors are worked around the rock on all sides
to the satisfaction of the soil engineer,
c) the portion of the rock above grade is covered with a second lift.
3. Material placed in each lift should be well graded. No unfilled spaces (voids) should be
permitted in the rock fill.
GENERAL GRADING GUIDELINES APPENDIX C
Page C- 7
Compaction Procedures
Compaction of rock fills is largely procedural. The following procedures have been found to
generally produce satisfactory compaction.
1. Provisions for routing of construction traffic over the fill should be implemented.
a) Placement should be by rock trucks crossing the lift being placed and dumping at its
edge.
b) The trucks should be routed so that each pass across the fill is via a different path
and that all areas are uniformly traversed.
c) The dumped piles should be knocked down and spread by a large dozer (D-8 or
larger suggested). (Water should be applied before and during spreading.)
2. Rock fill should be generously watered (sluiced)
a) Water should be applied by water trucks to the:
i) dump piles,
ii) front face of the lift being placed and,
iii) surface of the fill prior to compaction.
b) No material should be placed without adequate water.
c) The number of water trucks and water supply should be sufficient to provide
constant water.
d) Rock fill placement should be suspended when water trucks are unavailable:
i) for more than 5 minutes straight, or,
ii) for more than 10 minutes/hour.
3. In addition to the truck pattern and at the discretion of the soil engineer, large, rubber tired
compactors may be required.
a) The need for this equipment will depend largely on the ability of the operators to
provide complete and uniform coverage by wheel rolling with the trucks.
b) Other large compactors will also be considered by the soil engineer provided that
required compaction is achieved.
4. Placement and compaction of the rock fill is largely procedural. Observation by trenching
should be made to check:
a) the general segregation of rock size,
b) for any unfilled spaces between the large blocks, and
c) the matrix compaction and moisture content.
5. Test fills may be required to evaluate relative compaction of finer grained zones or as
deemed appropriate by the soil engineer.
a) A lift should be constructed by the methods proposed, as proposed
6. Frequency of the test trenching is to be at the discretion of the soil engineer. Control areas
may be used to evaluate the contractor’s procedures.
7. A minimum horizontal distance of 15 feet should be maintained from the face of the rock fill
and any finish slope face. At least the outer 15 feet should be built of conventional fill
materials.
Piping Potential and Filter Blankets
Where conventional fill is placed over rock fill, the potential for piping (migration) of the fine grained
material from the conventional fill into rock fills will need to be addressed.
The potential for particle migration is related to the grain size comparisons of the materials present
and in contact with each other. Provided that 15 percent of the finer soil is larger than the effective
GENERAL GRADING GUIDELINES APPENDIX C
Page C- 8
pore size of the coarse soil, then particle migration is substantially mitigated. This can be
accomplished with a well-graded matrix material for the rock fill and a zone of fill similar to the
matrix above it. The specific gradation of the fill materials placed during grading must be known to
evaluate the need for any type of filter that may be necessary to cap the rock fills. This,
unfortunately, can only be accurately determined during construction.
In the event that poorly graded matrix is used in the rock fills, properly graded filter blankets 2 to 3
feet thick separating rock fills and conventional fill may be needed. As an alternative, use of two
layers of filter fabric (Mirafi 700 x or equivalent) could be employed on top of the rock fill. In order
to mitigate excess puncturing, the surface of the rock fill should be well broken down and smoothed
prior to placing the filter fabric. The first layer of the fabric may then be placed and covered with
relatively permeable fill material (with respect to overlying material) 1 to 2 feet thick. The relative
permeable material should be compacted to fill standards. The second layer of fabric should be
placed and conventional fill placement continued.
Subdrainage
Rock fill areas should be tied to a subdrainage system. If conventional fill is placed that separates the
rock from the main canyon subdrain, then a secondary system should be installed. A system
consisting of an adequately graded base (3 to 4 percent to the lower side) with a collector system
and outlets may suffice.
Additionally, at approximately every 25 foot vertical interval, a collector system with outlets should
be placed at the interface of the rock fill and the conventional fill blanketing a fill slope.
Monitoring
Depending upon the depth of the rock fill and other factors, monitoring for settlement of the fill
areas may be needed following completion of grading. Typically, if rock fill depths exceed 40 feet,
monitoring would be recommend prior to construction of any settlement sensitive improvements.
Delays of 3 to 6 months or longer can be expected prior to the start of construction.
UTILITY TRENCH CONSTRUCTION AND BACKFILL
Utility trench excavation and backfill is the contractor’s responsibility. The geotechnical consultant
typically provides periodic observation and testing of these operations. While efforts are made to
make sufficient observations and tests to verify that the contractors’ methods and procedures are
adequate to achieve proper compaction, it is typically impractical to observe all backfill procedures.
As such, it is critical that the contractor use consistent backfill procedures.
Compaction methods vary for trench compaction and experience indicates many methods can be
successful. However, procedures that “worked” on previous projects may or may not prove
effective on a given site. The contractor(s) should outline the procedures proposed, so that we may
discuss them prior to construction. We will offer comments based on our knowledge of site
conditions and experience.
1. Utility trench backfill in slopes, structural areas, in streets and beneath flat work or
hardscape should be brought to at least optimum moisture and compacted to at least 90
percent of the laboratory standard. Soil should be moisture conditioned prior to placing in
the trench.
GENERAL GRADING GUIDELINES APPENDIX C
Page C- 9
2. Flooding and jetting are not typically recommended or acceptable for native soils. Flooding
or jetting may be used with select sand having a Sand Equivalent (SE) of 30 or higher. This is
typically limited to the following uses:
a) shallow (12 + inches) under slab interior trenches and,
b) as bedding in pipe zone.
The water should be allowed to dissipate prior to pouring slabs or completing trench
compaction.
3. Care should be taken not to place soils at high moisture content within the upper three feet
of the trench backfill in street areas, as overly wet soils may impact subgrade preparation.
Moisture may be reduced to 2% below optimum moisture in areas to be paved within the
upper three feet below sub grade.
4. Sand backfill should not be allowed in exterior trenches adjacent to and within an area
extending below a 1:1 projection from the outside bottom edge of a footing, unless it is
similar to the surrounding soil.
5. Trench compaction testing is generally at the discretion of the geotechnical consultant.
Testing frequency will be based on trench depth and the contractor’s procedures. A probing
rod would be used to assess the consistency of compaction between tested areas and
untested areas. If zones are found that are considered less compact than other areas, this
would be brought to the contractor’s attention.
JOB SAFETY
General
Personnel safety is a primary concern on all job sites. The following summaries are safety
considerations for use by all our employees on multi-employer construction sites. On ground
personnel are at highest risk of injury and possible fatality on grading construction projects. The
company recognizes that construction activities will vary on each site and that job site safety is the
contractor's responsibility. However, it is, imperative that all personnel be safety conscious to avoid
accidents and potential injury.
In an effort to minimize risks associated with geotechnical testing and observation, the following
precautions are to be implemented for the safety of our field personnel on grading and construction
projects.
1. Safety Meetings: Our field personnel are directed to attend the contractor's regularly
scheduled safety meetings.
2. Safety Vests: Safety vests are provided for and are to be worn by our personnel while on the
job site.
3. Safety Flags: Safety flags are provided to our field technicians; one is to be affixed to the
vehicle when on site, the other is to be placed atop the spoil pile on all test pits.
In the event that the contractor's representative observes any of our personnel not following the
above, we request that it be brought to the attention of our office.
Test Pits Location, Orientation and Clearance
The technician is responsible for selecting test pit locations. The primary concern is the technician's
safety. However, it is necessary to take sufficient tests at various locations to obtain a representative
sampling of the fill. As such, efforts will be made to coordinate locations with the grading
contractors authorized representatives (e.g. dump man, operator, supervisor, grade checker, etc.),
GENERAL GRADING GUIDELINES APPENDIX C
Page C- 10
and to select locations following or behind the established traffic pattern, preferably outside of
current traffic. The contractors authorized representative should direct excavation of the pit and
safety during the test period. Again, safety is the paramount concern.
Test pits should be excavated so that the spoil pile is placed away from oncoming traffic. The
technician's vehicle is to be placed next to the test pit, opposite the spoil pile. This necessitates that
the fill be maintained in a drivable condition. Alternatively, the contractor may opt to park a piece of
equipment in front of test pits, particularly in small fill areas or those with limited access.
A zone of non-encroachment should be established for all test pits (see diagram below). No grading
equipment should enter this zone during the test procedure. The zone should extend outward to
the sides approximately 50 feet from the center of the test pit and 100 feet in the direction of traffic
flow. This zone is established both for safety and to avoid excessive ground vibration, which typically
decreases test results.
50 ft Zone of
Non-Encroachment
50 ft Zone of
Non-Encroachment
Traffic Direction
Vehicle
parked here Test Pit Spoil
pile
Spoil
pile
Test Pit
SIDE VIEW
PLAN VIEW
TEST PIT SAFETY PLAN
10 0 ft Zone of
Non-Encroachment
Slope Tests
When taking slope tests, the technician should park their vehicle directly above or below the test
location on the slope. The contractor's representative should effectively keep all equipment at a safe
operation distance (e.g. 50 feet) away from the slope during testing.
The technician is directed to withdraw from the active portion of the fill as soon as possible following
testing. The technician's vehicle should be parked at the perimeter of the fill in a highly visible
location.
Trench Safety
It is the contractor's responsibility to provide safe access into trenches where compaction testing is
needed. Trenches for all utilities should be excavated in accordance with CAL-OSHA and any other
applicable safety standards. Safe conditions will be required to enable compaction testing of the
trench backfill.
GENERAL GRADING GUIDELINES APPENDIX C
Page C- 11
All utility trench excavations in excess of 5 feet deep, which a person enters, are to be shored or laid
back. Trench access should be provided in accordance with OSHA standards. Our personnel are
directed not to enter any trench by being lowered or "riding down" on the equipment.
Our personnel are directed not to enter any excavation which;
1. is 5 feet or deeper unless shored or laid back,
2. exit points or ladders are not provided,
3. displays any evidence of instability, has any loose rock or other debris which could fall into the
trench, or
4. displays any other evidence of any unsafe conditions regardless of depth.
If the contractor fails to provide safe access to trenches for compaction testing, our company policy
requires that the soil technician withdraws and notifies their supervisor. The contractor’s
representative will then be contacted in an effort to affect a solution. All backfill not tested due to
safety concerns or other reasons is subject to reprocessing and/or removal.
Procedures
In the event that the technician's safety is jeopardized or compromised as a result of the contractor's
failure to comply with any of the above, the technician is directed to inform both the developer's and
contractor's representatives. If the condition is not rectified, the technician is required, by company
policy, to immediately withdraw and notify their supervisor. The contractor’s representative will
then be contacted in an effort to affect a solution. No further testing will be performed until the
situation is rectified. Any fill placed in the interim can be considered unacceptable and subject to
reprocessing, recompaction or removal.
In the event that the soil technician does not comply with the above or other established safety
guidelines, we request that the contractor bring this to technician’s attention and notify our project
manager or office. Effective communication and coordination between the contractors'
representative and the field technician(s) is strongly encouraged in order to implement the above
safety program and safety in general.
The safety procedures outlined above should be discussed at the contractor's safety meetings. This
will serve to inform and remind equipment operators of these safety procedures particularly the
zone of non-encroachment.
The safety procedures outlined above should be discussed at the contractor's safety meetings. This
will serve to inform and remind equipment operators of these safety procedures particularly the
zone of non-encroachment.
1384 Poinsettia Avenue, Suite A
Vista, California 92083
TYPICAL CANYON
CLEANOUT
STANDARD GRADING
GUIDELINES
ALTERNATES
Original Ground
3’
Loose Surface Materials
PLATE G-1
Finish Grade
3’
Suitable
Material
Suitable
Material
6” Perforated Pipe in 9 cubic feet per LinealFoot Clean Gravel Wrapped in Filter Fabric
Construct Bencheswhere slope exceeds 5:1
Bottom of Cleanout to Be At
Least 1.5 Times the Width of
Compaction Equipment
4 feet typical
Slope to Drain
Original Ground
Loose Surface Materials
Finish Grade
Suitable
MaterialConstruct Bencheswhere slope exceeds 5:1
Bottom of Cleanout to Be AtLeast1.5 Times the Width ofCompaction Equipment
4 feet typical
Slope to Drain
6” Perforated Pipe in 9 cubic feetper Lineal Foot Clean GravelWrapped in Filter Fabric
TREATMENT ABOVE
NATURAL SLOPES
STANDARD GRADING
GUIDELINES
TYPICAL FILL SLOPE OVER
NATURAL DESCENDING SLOPE
Topsoil
Bedrock
PLATE G-2
Finish Grade
Fill Slope
Daylight Cut
Line per Plan
Project Removal
at 1 to 1
Min. 3 FeetCompacted Fill
Colluvium
Creep Zone
Minimum 15 Feet Wide
or 1.5 EquipmentWidths for Compaction
Toe of Fill Slope
per Plan
DAYLIGHT CUT AREA OVER
NATURAL DESCENDING SLOPE
Topsoil
Structural SetbackWithout Corrective Work
Project Removalat 1 to 1
Colluvium
Creep Zone
Min.
2 Feet
Minimum 15 Feet Wideor 1.5 EquipmentWidths for Compaction
Finish Grade
Bedrock
Min. 3 FeetCompacted Fill
Min.2 Feet
Compacted Fill
Compacted Fill
1384 Poinsettia Avenue, Suite A
Vista, California 92081-8505
Topsoil
Colluvium
Creep Zone
COMMON FILL
SLOPE KEYS
STANDARD GRADING
GUIDELINES
TYPICAL FILL SLOPE OVER
CUT SLOPE
Topsoil
Bedrock
PLATE G-3
Finish Grade
2: 1 Fill Slope
4’ Typical
Colluvium
Creep Zone
Minimum 15 Feet Wideor 1.5 EquipmentWidths for Compaction
Toe of Fill Slope
per Plan
TYPICAL FILL SLOPE
Bedrock or
Suitable Dense Material
Minimum compacted fill requiredto provide lateral support.
Excavate key if width or depthless than indicated in table above
Cut Slope
SLOPEHEIGHT
MIN. KEY
WIDTH
MIN. KEY
DEPTH
5
10
15
20
25
>25
7
10
15
15
15
SEE TEXT
1
1.5
2
2.5
3
CONTRACTOR TO VERIFYWITH SOIL ENGINEERPRIOR TO CONSTRUCTION
1384 Poinsettia Avenue, Suite A
Vista, California 92081-8505
NOTES:
1)SOIL FILL OVER WINDROW SHOULE BE 7 FEET OR PER JURISDUICTIONAL STANDARDS AND SUFFICIENTFOR FUTURE EXCAVATIONS TO AVOID ROCKS
2)MAXIMUM ROCK SIZE IN WINDROWS IS 4 FEET MINIMUM DIAMETER
3)SOIL AROUND WINDROWS TO BE SANDY MATERIAL SUBJECT TO SOIL ENGINEER ACCEPTANCE
4)SPACING AND CLEARANCES MUST BE SUFFICIENT TO ALLOW FOR PROPER COMPACTION
5)INDIVDUAL LARGE ROCKS MAY BE BURIED IN PITS.
ROCK BURIAL
DETAILS
STANDARD GRADING
GUIDELINES
PLATE G-4
SEE NOTE 1
15’
MIN.3’ MIN.
3’ MIN.
MINIMUM 15’ CLEAR OR
1.5 EQUIPMENT WIDTHS
FOR COMPACTION
STAGGER ROWS
HORIZONTALLY
NO ROCKS IN
THIS ZONE
CROSS SECTIONAL VIEW
FINISH GRADE
FILL SLOPE
PLAN VIEW
FILL SLOPE
MINIMUM 15’ CLEAR OR 1.5 EQUIPMENTWIDTHS FOR COMPACTION
MINIMUM 15’ CLEAR OR 1.5 EQUIPMENT
WIDTHS FOR COMPACTION
PLACE ROCKS END TO END
DO NOT PILE OR STACK ROCKS
SOIL TO BE PLACE AROUND AND OVER ROCKS THEN FLOODED INTOVOIDS. MUST COMPACT AROUND AND OVER EACH ROCK WINDROW
1384 Poinsettia Avenue, Suite A
Vista, California 92081-8505
6” Perforated Pipe in 6 cubic
feet per lineal foot clean gravel
wrapped in filter fabric outlet
pipe to gravity flow
BEDROCK COMPACTED FILL
MIN. 3 FEETCOMPACTED FILL
TERRACE DRAIN
AS REQUIRED
2
1
MIN. 15 FEET WIDE OR 1.5 EQUIPMENT
WIDTHS FOR COMPACTION
MIN. 2 FEET
EMBEDDMENT
1384 Poinsettia Avenue, Suite A
Vista, California 92083
Typical Buttress and
Stabilization Fill PLATE G-5
4” or 6” Perforated Pipe in 6 cubicfeet per lineal foot clean gravelwrapped in filter fabric outlet pipeto gravity flow at 2% min.
TRANSITION &
UNDERCUT LOTS PLATE G-6
TRANSITION LOT
PROPSED FINISH GRADE
COMPETENT MATERIAL
4’MIN.
OVEREXCAVATE ANDRECOMPACT
PROPOSED STRUCTURE
COMPACTED FILL
3 1
OVEREXCAVATION AND BENCHING NOTTO EXCEED INCLINATION OF 3:1 (H:V)
UNDERCUT LOT
PROPSED FINISH GRADE
PROPOSED STRUCTURE
4’MIN.
COMPETENT MATERIAL
COMPACTED FILL
OVEREXCAVATE ANDRECOMPACTOVEREXCAVATION TO HAVE 1%FALL TOWARD FRONT OF LOT
Notes:1.Removed/overexcavated soils should be recompacted in accordance with recommendations included in the text of the report.2.Location of cut/fill transition should verified in the field during site grading.
STANDARD GRADING
GUIDELINES1384 Poinsettia Avenue, Suite A
Vista, California 92081-8505