HomeMy WebLinkAboutMS 2018-0012; THREE ON CHERRY; GEOTECHNICAL INVESTIGATION; 2022-12-21December 21, 2022
Jason Geldert
Community Development Department
City of Carlsbad
1635 Faraday Avenue
Carlsbad, California 92008-7314
SUBJECT:
Dear Mr. Geldert:
File No. 1106E6-22
Proposed Retaining Wall
160 Cherry A venue
City of Carlsbad, CA 92008
P.O. Box 1195
Lakeside, California
92040
(619) 443-0060
In accordance with your request, we have reviewed the current grading plan regarding the
proposed SDRSD C-2 retaining wall with a maximum height of 3 feet, 8 inches. In lieu of
the proposed shoring wall, the stability of the proposed cut should be maintained by
construction methods. During construction, a maximum of 20 foot sections should be
exposed at a time to ensure that the neighboring screen wall is not undermined.
If we can be of any further assistance, please do not hesitate to contact our office. This
opportunity to be of service is sincerely appreciated.
Respectfully submitted,
e:74~6:;
Chin C. Chen, RPE C34442
CCC/jgr
IIN, THITERI . . ' -------------------------------
December 8, 2022
Jason Geldert
Community Development Department
City of Carlsbad
1635 Faraday Avenue
Carlsbad, California 92008-7314
SUBJECT: File No.1106E6-22
Proposed Retaining Wall
160 Cherry A venue
City of Carlsbad, CA 92008
Dear Mr. Geldert:
P.O. Box 1195
Lakeside, California
92040
(619) 443-0060
In accordance with your request, we have reviewed the current grading plan regarding the
proposed 30 inch SDRSD C-2 retaining wall. In lieu of the proposed shoring wall, the
stability of the proposed cut should be maintained by construction methods. During
construction, a maximum of 20 foot sections should be exposed at a time to ensure that the
neighboring screen wall is not undermined.
If we can be of any further assistance, please do not hesitate to contact our office. This
opportunity to be of service is sincerely appreciated.
Respectfully submitted,
ltt■, TEITERI
August 26, 2022
Allen Di Donato,
Di Donato Associates Architecture
3939 First Avenue, Suite 100
San Diego, California 92103
SUBJECT:
Dear Mr. Di Donato:
File No. 1106E6-22
Stormwater classification for Hydrologic Soil Group Type.
160 Cherry A venue
City of Carlsbad, CA 92008
P.O. Box 1195
Lakeside, California
92040
(619) 443-0060
In accordance with your request, two representatives of our firm have visited your site to
inspect the general site conditions as stated in the Geotechnical Investigation report by
Toro International, dated: September 17, 2021, project number: 03-125.7. This addendum
answers the question from the civil engineer Christensen Engineering, for using the
Hydrologic soil group B, by NRCS, Natural Resources Conservation Service, in their
Hydrology Study within the Coefficient Determination process.
The City of Carlsbad has requested a clarification of the usage of maps from the Natural
Resources Conservation Service (NRCS), as compared to usage of maps produced by
agencies such as the United States Geological Survey (USGS) and the California
Geological Survey (CGS), and others.
Professional geologists and engineering geologists routinely utilize geologic maps
produced by USGS and CGS and other agencies and authors, to assist them in identifying
underlying formations, or geologic units identified by rock type, age and structure at
specific locations. These geologic units have no particular or practical applicability to
agricultural uses and are used by geologists to map, identify and understand underlying
older sedimentary, igneous or metamorphic rocks, and not recent soils which may overlie
these rocks. Waterlaid sediments (alluvium and lake sediments), colluvium, landslide
1
Di Donato Associates File No. 1106E6-22 August 26, 2022
deposits which may not be lithified to the extent where they can be called "rock" but are
still older than the most recent surface soils, are also identified on some maps.
For example, a 2007 map produced by CGS, namely Geologic map of the Oceanside
30x60 minute quadrangle, indicates that the subject property is underlain by "Old
Paralics", units 6-7, with the map geologic symbol Qop6-7_ In the descriptive pamphlet by
CGS, these geologic units are described as follows:
"Old Paralic Deposits, Units 6 and 7: late to middle Pleistocene age (approximately one
million years ago): Poorly sorted, moderately permeable, reddish-brown, interfingered
strandline, beach, estuarine and colluvial deposits composed of siltstone, sandstone and
conglomerate. These deposits rest on the 9-11 m (ms!) and 22-23 m (msl) Bird Rock and
Nest or terraces. "
These units correlate with the marine terrace units described by and included in the soils
report by Toro International, dated September 17, 2021, which used 1992? Geologic maps.
In the case of the paralic units underlying the subject property, the maps referred to above
depict and describe sedimentary bedrock, formerly silt, sand and stream sediments which
have been lithified over time ( over millions of years) into rock, with unit thicknesses of
tens to sometimes hundreds of feet. The geologic units are not meant to designate and
describe surficial soil units which may be less than ten feet in thickness, and have formed
more recently, over thousands of years, through the processes of physical, biological and
chemical weathering, and transport by wind and water.
The NRCS, Natural Resources Conservation Service, maps are produced by the United
States Department of Agriculture and other federal agencies. These maps are meant to
be land use planning tools with an emphasis on agricultural, drainage and infiltration
properties of soils in the survey areas. The preface to the Custom Soil Resource Report for
this property states that "Soil surveys identify soil properties that are used in making
various land use or land treatment decisions. . ..... soil survey information can be used for
general farm, local, and wider area planning"
Professional geologists do not typically use the same soil units as the NRCS. When
geologists and engineering geologists describe soils, they use the Unified Soil
Classification System (USCS), which is based primarily on texture (grain size), e.g.,
2
Di Donato Associates File No. 1106E6-22 August 26, 2022
sandy clay, silty sand, etc. These classifications have applicability to the engineering
properties of soils such as expansive characteristics and excavatability.
Geologists use geologic unit maps symbols as discussed above, to label underlying
geologic rock units.
Soil and rock identification systems used by entities such as the USGS and CGS are
entirely different in origin, emphasis, applicability and use than systems used by the NRCS
and others. Map units shown on CGS maps and NRCS maps are different and are never
meant to correspond or correlate with one another, since classification, use, applicability
and mapping methods are entirely different. Indeed, the units will never correlate
precisely.
As a brief example, a soil developed atop a volcanic basalt lava flow in a rainy climate in
western Oregon may be primarily clay; however, the same basalt in the dry climate of
eastern Oregon may develop a top soil that is a silty or clayey sand. The geologic map unit
may be the same, but the NRCS soil designation may be different. Soil development and
characteristics can be variable even if developed over the same geologic formation,
depending on topography, climate, weathering rates, biologic activity and other factors.
HYDROLOGIC SOIL GROUP
Hydrologic studies are invaluable for estimating the run-off from a given area and designing
flood control conditions along with structures adequate to handle the runoff storm water. The
County of San Diego Planning and Land Use had joined with NRCS, United States
Department of Agriculture, Soil Conservation Service and Forest Service, UC Davis, and
United States Department of the Interior in the late 1960's to do soils mapping Part I and Part
II along with the maps showing the soil survey and data information for the entire county,
completed in December 1973. They have established four Groups from A to D, with A being
the best case and D being the worst case. The site falls within two Group "A and C" prior to
site development.
The Underlying Soil Belongs to Hydrologic Soil Group: NRCS Type B
The soils that were encountered within the soil report by Toro International were considered
to be Very low-expansive, Expansion Index 8 (with the valve ranging from :::::_o to :::_21) with
respect to change in volume along with change in moisture content.
3
Di Donato Associates File No. l 106E6-22 August 26, 2022
STORM WATER MANAGEMENT
We understand storm water management devices are being used in accordance with the 2019,
Model BMP Design Manual, County of San Diego Region, commonly referred to as the
Storm Water Standards (SWS). There is not a potential for distress to improvements and
properties located hydrologically down gradient or adjacent to these BMP devises. Factors
such as the amount of water to be detained and its residence time are to be considered by the
design engineer. As reviewing the native soil conditions from the field and the soil description
from NRCS, Natural Resources Conservation Service, the soil permeability has an important
effect on seepage transmission and the potential adverse impacts that may occur if the storm
water management features are not properly designed and constructed.
SITE EROSION CONTROL
During the construction, surface water should be controlled via berms, gravel bags and/or
sandbags, silt fence, straw wattles, siltation basins, while maintaining positive surface
grades or other methods to avoid damage to the finish work or adjoining properties. All
site entrances and exits must have coarse gravel or steel shaker plates to minimize offsite
sediment tracking. Best management Practices (BMP's) must be used to protect storm
drains and minimize pollution. The contractor should take measures to prevent erosion of
graded areas until such time as permanent drainage and erosion control measures have
been installed. After completion of grading, all excavated surfaces should exhibit
positive drainage and eliminate areas where water might pond.
SITE AND SURFACE DRAINAGE
Drainage at the site should be directed away from foundations, collected and tight lined to
appropriate discharge points. Consideration may be given to collecting roof drainage by
eave gutters and directing it away from foundations via non-erosive devices. Water, either
natural or from irrigation, should not be permitted to pond, saturate the surface soils or
flow towards the foundation.
The site should be graded and maintained such that surface drainage is directed away from
structures in accordance with 2016, CBC 1803.3, or other applicable standards.
Underground utilities should be leak free. Utilities and irrigation lines should be checked
periodically for leaks and detected leaks should be repaired promptly. Detrimental soil
4
Di Donato Associates File No. 1106E6-22 August 26, 2022
movement could occur if water is allowed to infiltrate the soil for prolonged periods of
time.
Landscaping requiring a heavy irrigation schedule should not be planted adjacent to
foundations or paved areas. The type of drainage issues found within the project and
materials specified and used should be determined by the Engineer of Record.
GROUNDWATER AND SURFACE WATERS
There was no indication of a near-surface groundwater table within the soils report by Toro
International or perched groundwater. Although in our Professional Opinion the
groundwater is not expected to be a significant constraint to the proposed development, our
experience indicates that near-surface groundwater conditions can develop in areas where
no such groundwater conditions previously existed, especially in areas where a substantial
increase in surface water infiltration results from landscape irrigation or unusually heavy
precipitation. It is anticipated from the grading plan the site development will include
appropriate drainage provisions for control and discharge of surface water runoff. The type
of drainage issues found within the project and materials specified and used should be
determined by the Civil Engineer. The type of plants and soil specified along with proper
irrigation used should be determined by the Landscape Architect.
OSHA, requirements below should be used for temporary cuts in excess of 4 feet should meet
OSHA standards. The proposed temporary cuts for the project are estimated to be
approximately 3 .5 feet or less.
It should be noted that the contractor is solely responsible for designing and constructing
stable, temporary excavations and may need to shore, slope, or bench the sides of trench
excavations as required to maintain the stability of the excavation sides. The contractor's
"competent person", as defined in the OSHA Construction Standards for Excavations, 29
CFR, Part 1926, should evaluate the soil exposed in the excavations as part of the
contractor's safety process. Temporary cut slopes should be constructed in accordance with
the recommendations presented in this section. In no other case should slope height, slope
inclination, or excavation depth, including utility trench excavation depth, exceed those
specified in local, state, and federal safety regulations.
5
Di Donato Associates File No. 1106E6-22 August 26, 2022
0 8° Soil
If we can be of any further assistance, please do not hesitate to contact our office. This
opportunity to be of service is sincerely appreciated.
Respectfully submitted,
Chin C. Chen, RPE C34442
CCC/jgr
Bryan Miller-Hicks, CEG 1323, PG 4130
6
September 20, 2021
TI Project No. 03-125.7
Di Donato Associates
3939 First Avenue, Suite 100
San Diego, California 92103
Subject: Response to Comments of City of Carlsbad, Performed by Hetherington
Engineering, Dated April 13, 2021 regarding Proposed Multi-Family
Building, Three on Cherry, 160 Cherry Avenue, Carlsbad, California
In accordance with your request, we have prepared the following response to the
pertinent City’s Comments dated April 13, 2021 (please see the Attachment 1).
1. Response. Noted. The report was updated to reflect the 2019 California Building
Code and ASCE 7-16. Please see the referenced report.
2. Response. Based on our geotechnical review of the grading plan, site plan and
foundation plan (see Attachment 2), all recommendations stated in the referenced
geotechnical report and this letter report have been implemented appropriately.
The proposed improvements will be suitable for the intended use and will not
have an adverse impact on the adjacent properties.
3. Response. Please see Attachment 3.
4. Response. The proposed site as well as the overall site is a relatively flat area.
The grading plans indicate that cut of less than 2 feet is proposed to achieve the
proposed pad grades. In addition, overexcavation of about 3 feet thick below the
existing grade is proposed underneath and 3 feet beyond the building pads.
Retaining walls less than 3 feet high will be constructed on the perimeters of the
property to accommodate the grade differences with the adjacent properties.
5. Response. ASTM D4829.
6. Response. Boring No. 1 in our report encountered Pleistocene terrace deposits to
the full depth of the boring that was 21.5 feet deep. To respond to Comment No.
3 we inspected the approximately 30 feet high sea bluff opposite the intersection
of Cherry Avenue and Carlsbad Boulevard.
September 20, 2021
Response to City’s Comments
Page: 2
Our inspection indicates that the bluff is composed of moderately cemented,
massively to thickly bedded, medium-grained, red-brown sandstone for the full
height of the bluff (approximately 30 feet.) The contact with the Santiago
Formation is shown on the geologic map of the Oceanside, San Luis Rey and San
Marcos Quadrangles (Tan and Kennedy, 1996) as occurring near the base of the
bluff. At this location the contact is now obscured by a pedestrian walkway and
retaining/sea wall.
Based on our inspection and mapping by Tan and Kennedy (1996) we conclude
that the terrace deposits on the sea-bluff are between 30 and 40 feet thick. The
lowest elevation on the site according to the project grading plans is 54 feet and
the elevation of the top of bluff is 48 feet. We estimate that the terrace
deposit/Santiago Formation contact dips westward at a gradient on the order of
2% (+/-) which is approximately the same inclination as the gradient of the
ground surface between the site and bluff edge.
Accordingly, the thickness of the terrace deposits below the site will be
essentially the same as the thickness exposed at the face of the bluff. Since the
Santiago Formation lies at a depth of over 30 feet below the site, it will not be
encountered in the proposed grading and its presence at that depth will not affect
the development of the site.
7. Response. Subsurface conditions were explored on October 11, 2018 by drilling
one boring to a maximum depth of approximately 21.5 feet below the existing
grade below the existing grade. The drilled borehole was advanced by an 8-inch-
diameter-hollow-flight-auger drilling rig mounted to a truck. The drilled borehole
was located in the field by tape measurements from known landmarks. Its
location as shown is therefore within the accuracy of such measurements.
The field explorations were performed under supervision of our engineer who
prepared detailed logs of the boring, classified the soil encountered, and obtained
soil samples for laboratory testing.
Relatively undisturbed soil samples were obtained by means of driving a 2.5-inch
diameter sampler (California Ring Samplers) having a hammer weight and drop
of 140 pounds and 30 inches, respectively at 2 and 5 feet below the ground
surface. Standard Penetration Tests (SPT) tests were also carried out at 10, 15
and 20 feet below the ground surface. Small bulk samples obtained from the SPT
tests were collected for further evaluation in the laboratory.
8. Response. The proposed development including grading will not have an adverse
impact on the adjacent properties and improvements provided all the
recommendations stated in the referenced report are implemented.
September 20, 2021
Response to City’s Comments
Page: 3
9. Response. The approved foundation embedment materials should have a
minimum relative compaction of 90% based on maximum dry density performed
in accordance with ASTM D-1557.
10. Response. The potential total and differential settlement is ½ and ¼ inch,
respectively within a span of 40 feet.
11. Response. The minimum thickness for concrete flatworks is 4 inches in order to
minimize potential for excessive cracks. In addition, construction joints or
weakened plane joints should be provided at 6-foot frequent intervals.
12. Response. Please see the list of references below.
Sincerely,
TORO INTERNATIONAL
Michael W. Hart, CEG 706 Hantoro Walujono, GE 2164
Senior Engineering Geologist Principal Engineer
Attachments: 1. Copy of City of Carlsbad Review Sheet, performed by Hetherington
Engineering and dated April 13, 2021
2. Copy of Grading plan, Site plan and Foundation plan prepared by
DiDonato Associates and dated September 14, 2020
3. Site Plan and Geologic Map
References: Toro International, 2021, Preliminary Geotechnical Investigation for
Proposed Multi-Family Building, Three on Cherry, 160 Cherry Avenue,
Carlsbad, California, TI Project No. 03-125.7 and dated September 15,
2021(rev)
Tan, S.S., Kennedy, M.P., 1996, Geologic Maps of the Oceanside, San
Luis Rey, and San Marcos 7.5’ Quadrangles, D.M.G. Open-File Report
96-02
EXP. 3/31/23
HETHERINGTON ENGINEERING, INC.
SOIL & FOUNDATION ENGINEE RING • ENGINEERI NG GEOLOGY • HYDROGEOLOGY
City of Carlsbad
Land Development Engineering
1635 Faraday Avenue
Carl sbad, California 92008
Attention: Ms. Jennifer Horodyski
Subject: THIRD-PARTY GEOTECHNICAL REVIEW (FIRST)
Proposed Multi-Family Building
Three on Cherry
160 Cherry A venue
Carlsbad, California
Project ID: GR2021-00 l 1/MS2018-0012
April J 3, 2021
Project No. 9343.1
Log No. 21390
References: I. "Preliminary Geotechnical Investigation For Proposed Multi-Family
Building, Three on Cherry, 160 Cherry Avenue, Carlsbad,
California", by Toro International, dated October 26, 2018.
2. "Grading Plans For: Three on Cherry", by Chri stenson Engineering,
undated (Sheets I thro ugh 5 of 5).
Dear Ms. Horodyski:
In accordance with your request, Hetherington Engineering, Inc. has provided third-party
geotechnical review of Reference 1. The fol lowing comments are provided for analyses
and/or response by the Geotechnical Consultant.
REVIEW OF GEOTECHNICAL REPORT
I . Due to the age of the "Geotechnical Investigation ... " (Reference!), the
Consultant should provide an updated geotechnical report addressing the plans,
and provide updated seismic design, grading and fo undation recommendations
consistent with the 2019 California Building Code and ASCE 7-16, as necessary.
2. The Consultant should review the project grading and fo undation plans, provide
any additional geotechnical recommendations considered necessary, and confirm
that the plans have been prepared in accordance with the geotechnical
recommendations provided in the referenced report.
5365 Avenida Encinas, Suite A • Carlsbad, CA 92008-4369 • (760) 931-191 7 • Fax (760) 931-0545
333 Third Stree • Laguna Beach, CA 9265 • (949) 715-5440 • Fax (949) 715-5442
www.hetheringtonengineering.com
THIRD-PARTY GEOTECHNICAL REV IEW (F IRST)
Project No. 9343.1
Log No. 2 1390
April 13, 2021
Page 2
3. The Consultant should provide an updated geotechnical map/plot plan utilizing
the latest grading plan for the project to clearly show (at minimum) a) existing site
topography, b) proposed structures/improvements, c)proposed finished grades, d)
locations of the subsurface explo ration, e) geologic contacts, and f) remedial
grading limits, etc.
4. The Consultant should provide a detailed description of proposed site grading,
structures/improvements, foundation type etc.
5. The Consultant should provide the ASTM standards used for the expansion index
test.
6. The Consultant indicates the terrace deposits underlying the site are over I 00-feet
thick. This has not been reported by others. The Consultant should review the
published geologic maps or consultants reports of the area and update the
expected conditions deeper than the drilled borings.
7. The Consultant should provide a description of the field sampling procedures
utilized.
8. The Consultant should provide a statement regarding the impact of the proposed
grading and construction on adjacent properties and improvements.
9. The Consultant should provide a description of what are considered approved
foundation embedment materials.
l 0. The Consultant should address expected total and differential settlement due to
grading and foundation loads.
11. The Consultant should provide hardscape recommendations (thickness,
reinforcement, joints, etc.).
12. The Consultant should provide an updated list of published maps/reports and
codes used in the preparation of the report.
HETHERINGTON ENGINEERING, INC.
THIRD-PARTY GE0TECHNICAL REVlEW (F IRST)
Project No. 9343.1
Log No. 21390
April 13, 2021
Page 3
The opportunity to be of service is sincerely appreciated. If you have any questions
regarding this review, please contact this office at your convenience.
Si ncerely,
HETHERINGTON ENGINEERING, INC.
Mark D. Hetherington
Civil Engineer 30488
Geotechnical Engi neer 3
( expires 3/31 /22)
Distribution: 1-via e-mai I (Jennifer.Horodyski@carlsbadca.gov)
1-via e-mail (Amy.Wickerham@carlsbadca.gov)
HETHERINGTON ENGINEERING, INC.
CONSTRUCTION NOTES
(D PROPOSED 2· WATER SERVICE PER CMWD W-4
0 PROPOSED 6" PVC SEWER LATERAL
CONNECTED TO THE MANHOLE
(D REMOVE AND REPLACE EX DRIVEWAY
WITH NEW 12' DRIVEWAY
PER SDRSD G-14B & CARLSBAD S-12
PROPOSED PERVIOUS CONCRETE SURFACE
(TYPICAL)
AREA DRAIN (TYPICAL)
MASONRY RETAINING WALL PER SDRSD C-3
PROPOSED PVC DRAIN (TYPICAL)
SEWER CLEANOUT PER CMWD S-6 (TYPICAL)
DOWNSPOUT (TYPICAL)
EX IMPROVEMENTS TO BE REMOVED
@ TRASHED BIN
@ PROPOSED TYPE A-4 CLEANOUT PER SDRSD D-09, D-13 & D-15
WITH PUMP TO CONVEY SITE RUNOFF TO CURB OUTLET
@ CURB OUTLET PER SDRSD D-25
QIOO = 0.44 CFS
VIOO = 2.44 FPS
iJl) EX WATER SERVICE TO BE REMOVED.
(@ PRESSURE LINE FROM PUMP IN CATCH BASIN
TO GRAVITY CATCH BASIN
(@ EX MASONRY WALL TO BE STRUCTUALL Y EVALUATED
AND REPLACED, IF REQUIRED
!fl) PROPOSED 2• BACKFLOW PREVENTER PER CMWD W-20
@ PROPOSED 2• WATER METER
@; PROPOSED ONSITE CURB
@ REMOVE EXISTING SEWER LATERAL CAP WYE FROM EX MAIN
(i}) EXISTING WATER METER BOX TO BE REMOVED
@ END OF SEWER MAIN/EX. SEWER CLEANOUT
<a 2424 CATCH BASIN TO CAPTURE OFFS/TE RUNOFF
@ CONNECT TO SEWER W/6x6 WYE
@ PROPOSED KEYSTONE WALL
@ PROPOSED TRENCH RESURFACING PER CARLSBAD GS-25/GS-26
@ POINT OF CONNECTION FOR WALL SUB-DRAIN
NOTE:
ALL ROOF RUNOFF (IMPERVIOUS AREA) WILL FLOW TO
PERVIOUS AREAS INCLUDING PAVEMENT AND LANDSCAPED
AREAS BEFORE BEING CONVEYED OFFS/TE
SCALE: 1"
0 10 20 30 40
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UNAUTHORIZED CHANGES & USES
CAUTION: The Engineer preparing these plans will not be responsible for,
or liable for, unauthorized change to or uses of these plans. All changes
to the plans must be in writing and must be approved by the preparer of
these plans.
J· <:i"· 'o ~
--<:J"'
,.-? ,.-?
"AS BUILT"
( -
RCE EXP. DATE
,. REVIEWED BY:
INSPECTOR DATE
I SH~ET I CITY OF CARLSBAD m ENGINEERING DEPARTMENT
GRADING PLANS FOR:
THREE ON CHERRY
GR 2021-0011 GRADING PLAN SHEETpuD 2018-0008
APPROVED: JASON S. GELDERT
ENGINEERING MANAGER RCE 63912 EXPIRES 9/30/22 DATE
/1\ DWN BY: • "1" PROJECT NO. DRAWING NO. DATE INITIAL DATE INITIAL DATE INITIAL CHKD BY:
ENGINEER OF WORK REVISION DESCRIPTION OTHER APPROVAL CITY APPROVAL RVWD BY: MS 2018-0012 530-4A
JN 2018-119
EXISTING WALL
SCALE: 1 "
0 10 20 JO
PROPOSED
CURB
LIMITS OF OVER EXCA VAT/ON PROPOSED
PERVIOUS
PAVEMENT
~ PROPERTY LINE
57.00 TW
54.20 FG
PROPOSED WALL
{
EXISTING
GROUND
5% MIN
LIMITS OF OVER EXCA VAT/ON
55.25 FF
SECTION "c" -"c"
NOT TO SCALE
40
SECTION "B" -"B"
UNIT C
NOT TO SCALE
PROPERTY LINE
57.00 TW
54.50 FG
EXISTING 6'
WOODEN FENCE
1.2 J
II
/PROPOSED
PROPOSED
LANDSCAPE
t KEYSTONE WALL l [EXISTING -li -~:5 EG_ _ GROUND
-rr-11-11 ...ljf
-1 I -1 I -1 I -11 1ff _lff _lff ,
'-I= I= le I I '
-,1 -11 ,11 ;fF-lT
SECTION "o" -"o"
NOT TO SCALE
UNAUTHORIZED CHANGES & USES
CAU_TION: The Engineer preparing these plans will not be responsible ro,
or //able for, unauthorized change to or uses of these plans All changes
to the plans must be in writing and must be approved by' the preparer of
these plans.
..:
I
• I
"" y l
EL = 50.7'
I.E. INFLOW
<o
EL= 54.5
TOP OF COVER
,. .• Y= ,,-,.......,J·' ::i;\~\;\: '. .....
·> •
a~, , ,-:~:,-;.
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EL = 52.7
I.E. OUTFLOW
~ 1.5 HP GOULDS PUMPS
RESERVE
_04 SERIES
MODEL 3888D4
WS15D4M
STORM CLEANOUT WITH PUMP
DETAIL
D-09 TYPE A4
NOT TO SCALE
NOTE: PUMP SWITCH TO
AU TOMA TICALL Y TURN ON
AND OFF SHALL BE INCLUDED.
SECTION "A" -"A"
DATE
NOT TO SCALE
,--:--~----,------~~-,,, 0.35' PERVIOUS
, . . . .. . ,. CONCRETE
' z
PERVIOUS CONCRETE DETAIL
(NON-AUTO WALKWAY)
NOT TO SCALE
NOTE:
ACTUAL CROSS SECTION TO BE
DETERMINED BY GEOTECHNICAL
ENGINEER AT TIME OF GRADING
DEEPENED 6' TYPE G-1 CURB
0.70' PER VIOUS
CONCRETE
0.70' NO. 2 STONE
AGGREGATE BASE
PERVIOUS CONCRETE DETAIL (n < 9)
NOT TO SCALE
/1\
INITIAL
NOTE:
ACTUAL CROSS SECTION TO BE
DETERMINED BY GEOTECHNICAL ENGINEER AT TIME OF GRADING
DATE INITIAL
ENGINEER OF WORK REVISION DESCRIPTION OTHER APPROVAL
DATE
PROPOSED
PERVIOUS
PAVEMENT
I SH~ET I
GRADING
"AS BUILT"
RCE EXP. DATE
REVIEWED BY:
INSPECTOR DATE
CITY OF CARLSBAD m ENGINEERING DEPARTMENT
PLANS FOR:
THREE ON CHERRY
GR 2021-0011 GRADING PLAN SHEETpuD 2018 0008
APPROVED: JASON S. GELDERT
ENGINEERING MANAGER RCE 63912 EXPIRES 9/30/22 DATE
DWN BY: "'" PROJECT NO. INITIAL DRAWING NO.
CHKD BY:
CITY APPROVAL RVWD BY: MS 2018 0012 530 4A
JN 2018-119
56
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SITE AND GEOLOGIC MAP
THREE ON CHERRY
Geotechnical Engineering
PROJECT NO. 03-125.7
TORO INTERNATIONAL LEGEND
B-1: Approximate Location of Boring No. B-1
GEOTECHNICAL INVESTIGATION
for
MULTI-FAMILY BUILDING
THREE ON CHERRY
160 CHERRY AVENUE
CARLSBAD, CALIFORNIA
Prepared For:
DI DONATO ASSOCIATES
3939 FIRST AVENUE, SUITE 100
SAN DIEGO, CALIFORNIA 92103
Prepared By:
TORO INTERNATIONAL
1 LEAGUE # 61614
IRVINE, CA 92602
September 17, 2021(rev)
September 17, 2021(rev)
TI Project No. 03-125.7
Di Donato Associates
3939 First Avenue, Suite 100
San Diego, California 92103
Subject: Preliminary Geotechnical Investigation for Proposed Multi-Family Building, Three
on Cherry, 160 Cherry Avenue, Carlsbad, California
Toro International (TI) has completed preliminary geotechnical investigation for a proposed Multi-
Family Building, Three on Cherry, 160 Cherry Avenue, Carlsbad, California. This report presents
our findings, conclusions and recommendations for foundation design and construction of the
proposed multi-family building and its associated site preparation.
It is our opinion from a geotechnical viewpoint that the subject site is suitable for construction of the
proposed multi-family building provided our geotechnical recommendations presented in this report
are implemented in the design and during construction.
The recommendations developed in this report are based on empirical and analytical methods typical
of the standard of practice in California. We appreciate this opportunity to be of service.
Sincerely,
TORO INTERNATIONAL
Hantoro Walujono, GE 2164
Principal
EXP. 3/31/23
TABLE OF CONTENTS
1.0 INTRODUCTION ...............................................................................................................1
1.1 General.....................................................................................................................1
1.2 Proposed Development............................................................................................1
1.3 Site Description........................................................................................................1
1.4 Scope of Work .........................................................................................................3
2.0 FIELD EXPLORATION AND LABORATORY TESTING..............................................4
2.1 Field Exploration .....................................................................................................4
2.2 Laboratory Testing...................................................................................................4
3.0 SITE CONDITIONS............................................................................................................6
3.1 Geology....................................................................................................................6
3.2 Groundwater ............................................................................................................6
3.3 General Subsurface Conditions ...............................................................................6
4.0 SEISMICITY.......................................................................................................................7
4.1 General.....................................................................................................................7
4.2 Ground Motion ........................................................................................................7
4.3 Seismic Design.........................................................................................................8
4.4 Liquefaction Potential..............................................................................................8
5.0 CONCLUSIONS AND RECOMMENDATIONS ..............................................................9
5.1 General.....................................................................................................................9
5.2 Overexcavations/Removals .....................................................................................9
5.3 Grading and Earthwork............................................................................................9
5.4 Preliminary Foundation Recommendations...........................................................11
5.5 Temporary Excavation...........................................................................................12
5.6 Review of Plans.....................................................................................................12
5.7 Geotechnical Observation and Testing..................................................................13
6.0 REFERENCES ..................................................................................................................14
7.0 LIMITATIONS..................................................................................................................15
TABLE OF CONTENTS (CONT'D)
ILLUSTRATIONS
Section Page
List of Figures
Figure 1. Site Location Map....................................................................................................2
Figure 2. Boring Location Map...............................................................................................5
List of Tables
Table 1. Summary of Fault Parameters..................................................................................7
APPENDICES
Appendix A - Field Exploration
Appendix B - Laboratory Test Results
Appendix C - Design Maps Summary Report
Appendix D - Standard Guidelines for Grading
Three on Cherry
September 17, 2021(rev)
Page: 1
1.0 INTRODUCTION
1.1 General
This report presents the results of a preliminary geotechnical investigation performed by Toro
International (TI) for a proposed new three-story multi-family building, located at 160 Cherry
Avenue, Carlsbad, California. A Site Location Map is presented in Figure 1 showing the
approximate location of the project site.
The purpose of the preliminary geotechnical investigation is to provide geotechnical design
parameters and recommendations for construction of the new multi-family building and its
associated site preparation and grading.
Our preliminary geotechnical investigation was conducted based on an architectural plans, issued for
Preliminary Review, entitled “Three on Cherry, 160 Cherry Avenue, Carlsbad, CA 92008,” prepared
by Di Donato Associates and dated December 12, 2018.
1.2 Proposed Development
Our understanding of the proposed construction is based on the above mentioned site plans. It is
our understanding that the size of the building footprint will be about 3,600 square feet. We
anticipate that cut and/or fill will be minor (less than 3 feet thick).
1.3 Site Description
The proposed site of the new multi-family building is currently a single family home on an about
7,000 square-feet lot. The property consists of a one-story house and its front and backyards that are
covered by grasses and sparse trees. The proposed site as well as the overall site is a relatively flat
area.
Page: 2
FIGURE 1
SITE LOCATION MAP
THREE ON CHERRY
Geotechnical Engineering
PROJECT: 03-125.7
TORO INTERNATIONAL
Three on Cherry
September 17, 2021(rev)
Page: 3
1.4 Scope of Work
The scope of work for this preliminary geotechnical investigation consisted of the following:
• Review of published reports and geologic maps pertinent to the site
• Field exploration, consisting of drilling and logging one boring to a maximum depth of 21.5
feet
• Laboratory testing of selected soil samples considered representative of the subsurface
conditions to evaluate the pertinent engineering and physical characteristics of the
representative soils
• Evaluation of the general site geology, including geologic hazards which could affect the
proposed development
• Evaluation of ground shaking potential resulting from seismic events occurring on
significant faults in the area
• Engineering analyses of the collected data to develop geotechnical recommendations for
seismic analyses, foundation of the proposed new multi-family building and its site
preparation
• Preparation of this report presenting our findings, conclusions, and recommendations.
Three on Cherry
September 17, 2021(rev)
Page: 4
2.0 FIELD EXPLORATION AND LABORATORY TESTING
2.1 Field Exploration
The subsurface conditions were explored by drilling one borehole. The depth of the borehole is
about 21.5 feet below the existing ground surface. The approximate location of the boring is shown
on the Boring Location Map in Figure 2. Details of the field exploration, including the logs of the
boring, are presented in Appendix A.
2.2 Laboratory Testing
Soil samples considered representative of the subsurface conditions were tested to obtain or derive
relevant physical and engineering soil properties. Laboratory testing included moisture content and
in-situ density, sieve analyses, direct shear and soluble sulfate content.
Moisture content and in-situ density test results are shown in the Borings Logs in Appendix A. The
remaining laboratory test results are presented in Appendix B. Descriptions of the test methods are
also included in Appendix B.
FIGURE 1
BORING LOCATION MAP
THREE ON CHERRY
Geotechnical Engineering
PROJECT NO. 03-125.7
TORO INTERNATIONAL LEGEND
B-1: Approximate Location of Boring No. B-1
B-
1
Page: 5
Three on Cherry
September 17, 2021(rev)
Page: 6
3.0 SITE CONDITIONS
3.1 Geology
The subject site is located approximately 56 feet above mean sea level. The site is located within the
Pleistocene Marine and Terrace Marine Deposits (Rogers, 1992). The marine and marine terrace
deposits are Quaternary in age and the thickness is probably over than one hundred feet. The marine
materials consist primarily of a mixture of silt and sand.
3.2 Groundwater
Groundwater was not encountered during our field exploration; however the maximum depth of the
borehole is about 21.5 feet below the existing ground surface.
3.3 General Subsurface Conditions
In general, the proposed multi-family building is underlain primarily by silty sand and silty sand to
sand materials. The silty sand and silty sand to sand materials are classified as SM and SM-SP,
respectively according to the Unified Soil Classification System (USCS).
The consistency of the coarse-grained soils is primarily medium dense. The equivalent Standard
Penetration Test (SPT) blow-counts of the subsurface materials ranges from 13 to 22 blows-per-foot
(bpf) with an average of about 19 bpf.
The moisture content of the coarse-grained soils ranges from 2.2 to 8.4 percent with an average of
about 5.5 percent.
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September 17, 2021(rev)
Page: 7
4.0 SEISMICITY
4.1 General
Seismicity is a general term relating to the abrupt release of accumulated strain energy in the rock
materials of the earth’s crust in a given geographical area. The recurrence of accumulation and
subsequent release of strain have resulted in faults and systems of faults. The subject site is in
seismically active California.
4.2 Ground Motion
California Building Code (CBC). The most widely used technique for earthquake-resistant design
applied to low-rise structures is the California Building Code (CBC). The basic formulas used in the
CBC require determination of the site class, which represents the site soil properties at the site of
interest.
The nearest active fault is the Rose Canyon Fault, which is approximately 7.0 km away (Blake, T.
F., 1998). This fault and other nearest 7 faults, which could affect the site and the proposed
development, are listed in the following “Summary of Fault Parameters” as shown in Table 1.
TABLE 1. SUMMARY OF FAULT PARAMETERS
Fault Name
Approximate
Distance
(km)
Source Type
(A,B,C)
Maximum
Magnitude
(Mw)
Slip Rate
(mm/yr)
Fault Type
(SS,DS,BT)
Rose Canyon 7.0 B 6.9 1.50 SS
Newport-Inglewood (Offshore) 7.7 B 6.9 1.50 SS
Coronado Bank 33.0 B 7.4 3.00 SS
Elsinore-Temecula 39.6 B 6.8 5.00 SS
Elsinore-Julian 40.0 A 7.1 5.00 SS
Elsinore-Glen Ivy 54.7 B 6.8 5.00 SS
Palos Verdes 56.9 B 7.1 3.00 SS
Earthquake Valley 71.3 B 6.5 2.00 SS
Three on Cherry
September 17, 2021(rev)
Page: 8
4.3 Seismic Design
The 2019 CBC seismic zone for use in the seismic design formula is Site Class D. The Design Maps
Summary Report is included in Appendix C.
4.4 Liquefaction Potential
The subsurface soil consists predominantly of medium dense silty sand and silty sand to sand.
Groundwater was not encountered during our drilling; however the maximum depth of the borehole
is about 21.5 feet below the ground surface due to refusal encountered at that depth. Therefore,
based on the above-mentioned information, the subsurface soil materials at the proposed site are
considered not likely to liquefy during an earthquake.
Three on Cherry
September 17, 2021(rev)
Page: 9
5.0 CONCLUSIONS AND RECOMMENDATIONS
5.1 General
Based on the results of our preliminary geotechnical investigation, it is our opinion from a
geotechnical viewpoint that the subject site is suitable for the proposed development and its
associated grading provided our geotechnical recommendations presented in this report are
implemented.
The remainder of this report presents our recommendations in detail. These recommendations are
based on empirical and analytical methods typical of the standard of practice in Southern California.
Other professionals in the design team may have different concerns depending on their own
discipline and experience. Therefore, our recommendations should be considered as minimum and
should be superseded by more restrictive recommendations of other members of the design team or
the governing agencies, if applicable.
5.2 Overexcavations/Removals
The upper 24 to 36 inches of subsurface soils may consist of roots and organic. Therefore, we
recommend that all deleterious materials including uncertified fill materials should be discarded off
site and the upper three feet of the subsurface materials be removed and replaced with compacted
fills. Upon completion of removal of the upper three feet of subsurface soil materials, the
geotechnical consultant should evaluate the bottom of the excavation and may make further
recommendations accordingly. Onsite soils may be reused. The extent of the removal should be
within the proposed additional building footprint and 3 feet beyond them, if possible. The removal
bottom and compacted fill should be prepared in accordance with the recommendations stated in
Section 5.3 below.
5.3 Grading and Earthwork
General. All earthwork and grading for site development should be accomplished in accordance
with the attached Standard Guidelines for Grading Projects (Appendix D), Appendix J of the CBC,
and requirements of the regulatory agency. All special site preparation recommendations presented
in the following paragraphs will supersede those in the attached Standard Guidelines for Grading
Projects.
Site Preparation. Vegetation, organic soil, roots and other unsuitable material should be removed
from the building areas. Prior to the placement of fill, the existing ground should be scarified to a
depth of 6 inches, and recompacted.
Three on Cherry
September 17, 2021(rev)
Page: 10
Prior to pouring concrete, the subgrade soil for the concrete slab area should be wetted to a slightly
higher than the optimum moisture to a depth of 6 inches from the surface.
Fill Compaction. All fill and backfill to be placed in association with site development should be
accomplished at slightly over optimum moisture conditions. The minimum relative compaction
recommended for fill is 90 percent relative compaction based on maximum dry density performed in
accordance with ASTM D-1557.
Fill should be compacted by mechanical means in uniform horizontal loose lifts not exceeding 8
inches in thickness.
Fill Material. The on-site soils can be used for compacted fill. However, during grading operations,
soil types other than those analyzed in the geotechnical reports may be encountered by the
contractor. The geotechnical consultant should be notified to evaluate the suitability of those soils
for use as fill and as finished grade soils.
Imported fill materials should be approved by the Geotechnical Engineer prior to importing. Soils
exhibiting any expansion potential should not be used as import materials.
Both imported and on-site soils to be used as fill materials should be free of debris, organic and
cobbles over 6 inches in maximum dimension.
Site Drainage. Foundation and slab performance depends greatly on how well runoff waters drain
from the site. This is true both during construction and over the entire life of the structure. The
ground surface around structures should be graded so that water flows rapidly away from the
structures without ponding.
In general, we recommend impermeable areas such as paved and concrete flatwork within a
minimum distance of 10 feet from a building (measured perpendicular to the face of the wall) should
be sloped away at a minimum gradient of 2%. Other areas such as lawn and vegetated areas should
have minimum descending gradients of at least 5% within 10 feet of the building (measured
perpendicular to the face of the wall)
Utility Trenches. Bedding materials should consist of sand having Sand Equivalent not less than 30,
which may then be jetted. Existing soils may be utilized for trench backfill provided they are free of
organic materials and rocks over 6 inches in dimension.
The backfill should be uniformly compacted to at least 90% relative compaction based on maximum
density performed in accordance with ASTM D-1557.
Three on Cherry
September 17, 2021(rev)
Page: 11
5.4 Preliminary Foundation Recommendations
The following foundation recommendations were prepared without any information about the
structural configuration and maximum and average column loads of the new multi-family building.
Once the information is available, the following recommendations may be revised to reflect the
actual conditions of the proposed building.
In California, the foundation criteria given below have been generally observed to be practical in
mitigating the potential structural damage due to expansive soil pressures. The recommendations
below are based on our results of expansion index tests that indicate very low expansivity as defined
by the Section 1803 of CBC.
Additional expansion index tests need to be performed after completion of grading to verify that the
worst expansion index of the underlying soils is very low. If the test results indicate that the worst
condition of the underlying soils are not classified as very low, the recommendations below may be
adjusted accordingly.
Footing Design. The following minimum criteria should be adopted for the footing design in order
to maintain potential differential settlement less than ¼ inch:
a. Allowable Bearing Capacity: qall = 1,750 psf
b. Minimum Footing Width: 18 inches
c. Minimum Footing Depth: 24 inches
d. Minimum Reinforcement: 2 # 4 bars at both the top and bottom in
continuous footings
Notes:
i. Depth of footing is measured from the lowest adjacent grade.
ii. Allowable bearing capacity may be increased by one-third for short-term loadings.
iii. The above-mentioned footing dimension recommendations should not be considered
to preclude more restrictive criteria of regulating agencies or by a structural
engineer/architect.
iv. The design of the foundation system should be performed a structural engineer,
incorporating the geotechnical parameters described above.
Slab Design. The laboratory test results of the representative subgrade soils indicate that the
expansion index is 8, which falls within the very low expansion potential classification as defined by
the Section 1803 of current CBC. Therefore, no presaturation is required provided the compacted
fill will be placed in with moisture content one to two percent above the optimum.
Three on Cherry
September 17, 2021(rev)
Page: 12
The following recommendations should be incorporated for the slab-on-grade design:
a. The minimum thickness of slab-on-grade should be 5 inches.
b. The minimum steel reinforcement for slab-on-grade should be #3 located at mid-
height on 18-inch centers both ways
c. A modulus of subgrade reaction of 100 pounds per cubic inch (pci) may be utilized
for the slab design.
d. Modulus of Elasticity of Soil (Es): 1,000 pounds per square inch (psi)
e. Polyethylene Moisture Barrier (minimum 10-mil visqueen or equivalent) should be
placed-in below the slab; with approximately 2 inches of clean sand above the
moisture barrier and 2 inch of clean sand below the moisture barrier.
Cement Type. Based on the soluble sulfate test result, Type II cement and water-cement ratio of
0.45 or less may be used for concrete in contact with the on-site soils.
5.5 Temporary Excavation
Temporary excavation should be sloped back adequately to protect workers and protect against
sloughing. Based on our laboratory testing result and engineering analyses, the maximum gradient
for the temporary cut is 1:1 (horizontal:vertical) for onsite materials. Otherwise, temporary cut on
the onsite materials should be shored. Shoring should be designed and implemented by a specialty
contractor and should conform to the current Caltrans Trenching and Shoring Manual. Surcharge
loads due to the existing structure loading should be included in the design of the shoring, if any.
5.6 Review of Plans
The geotechnical consultant should review the final foundation and grading plans once they become
available in order to update and to provide detail and specific geotechnical recommendations for the
elements of the proposed development. The plans will also be compared to the site plan currently
used in the preparation of this report in order to evaluate the effect of any major changes with
respect to the geotechnical recommendations given in this report.
Three on Cherry
September 17, 2021(rev)
Page: 13
5.7 Geotechnical Observation and Testing
It is recommended that geotechnical observations and testing be performed by representatives of
Toro International at the following stages:
• Upon completion of remedial removals, prior to fill placement
• During removal bottom scarification
• During fill placement
• Upon completion of any footing excavation prior to pouring concrete
• During backfilling of any utility trenches
• When any unusual conditions are encountered
The geotechnical engineering firm providing geotechnical observation/testing shall assume the
responsibility of Geotechnical Engineer of Record.
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September 17, 2021(rev)
Page: 14
6.0 REFERENCES
1. Blake, T. F., 1998,”UBCSEIS”, A Computer Program for the Estimation of Uniform
Building Code Coefficients Using 3-D Fault Sources”, January 1998
2. California Building Code (CBC), 2019
3 Rogers, Thomas H., 1992, “Geologic Map of California, Santa Ana Sheet,” 1992
Three on Cherry
September 17, 2021(rev)
Page: 15
7.0 LIMITATIONS
This report is intended for the use of Di Donato Associates for the proposed multi-family building,
Three on Cherry, at 160 Cherry Avenue, Carlsbad, California. This report is based on the project as
described and the information obtained from the borings and other field investigations at the
approximate locations indicated on the plans. The findings are based on the results of the field,
laboratory, and office investigations combined with an interpolation and extrapolation of conditions
between and beyond the boring locations. The results reflect an interpretation of the direct evidence
obtained. The recommendations presented in this report are based on the assumption that an
appropriate level of field review (observations and tests) will be provided during construction. Toro
International should be notified of any pertinent changes in the project plans or if subsurface
conditions are found to vary from those described herein. Such changes or variations may require a
re-evaluation of the recommendations contained in this report.
The soil samples collected during this investigation are believed representative of the areas sampled.
However, soil conditions can vary significantly between and away from the locations sampled. As
in most projects, conditions revealed by additional subsurface investigations may be at variance with
preliminary findings. If this occurs, the geotechnical engineer must evaluate the changed condition,
and adjust the conclusions and recommendations provided herein, as necessary.
The data, opinions, and recommendations of this report are applicable to the specific design
element(s) and locations(s) which is (are) the subject of this report. They have no applicability to
any other design elements or to any other locations and any and all subsequent users accept any and
all liability resulting from any use or reuse of the data, opinions, and recommendations without the
prior written consent of Toro International.
Toro International has no responsibility for construction means, methods, techniques, sequences, or
procedures, or for safety precautions or programs in connection with the construction, for the acts or
omissions of the contractor, or any other person performing any of the construction, or for the failure
of any of them to carry out the construction in accordance with the Final Construction Drawings and
Specifications.
Services performed by Toro International have been conducted in a manner consistent with that level
of care and skill ordinarily exercised by members of the profession currently practicing in the same
locality under similar conditions. No other representation, express or implied, and no warranty or
guarantee is included or intended.
APPENDIX A - Field Exploration
Subsurface conditions were explored on October 11, 2018 by drilling one boring to a maximum
depth of approximately 21.5 feet below the existing grade below the existing grade. The drilled
borehole was advanced by an 8-inch-diameter-hollow-flight-auger drilling rig mounted to a truck.
The drilled borehole was located in the field by tape measurements from known landmarks. Its
location as shown is therefore within the accuracy of such measurements.
The field explorations were performed under supervision of our engineer who prepared detailed logs
of the borings, classified the soil encountered, and obtained soil samples for laboratory testing.
Relatively undisturbed soil samples were obtained by means of driving a 2.5-inch diameter sampler
(California Ring Samplers) having a hammer weight and drop of 140 pounds and 30 inches,
respectively at 2 and 5 feet below the ground surface. Standard Penetration Tests (SPT) tests were
also carried out at 10, 15 and 20 feet below the ground surface. Small bulk samples obtained from
the SPT tests were collected for further evaluation in the laboratory.
The Boring Logs show the type of sampler, weight and drop of the hammer, number of hammer
blows and soil stratigraphy. The soils were classified based on visual observations during the field
investigation and results of the laboratory testing. Soil classifications were conducted in accordance
with the Unified Soil Classification System.
TORO INTERNATIONAL
GEOTECHNICAL ENGINEERING
Project Name Three on Cherry Site Address 160 Cherry Avenue, Carlsbad
Project Number 03-125.7 Date 10/11/2018
Equipment Hollow Stem Flight Auger Drive Weight 140 lbs
Average Drop 30 inches Elevation (ft)56 (Assumed)
Hole Diameter 8 inches Engineer/Geologist HW
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GEOTECHNICAL DESCRIPTION
PLEISTOCENE MARINE AND MARINE TERRACE DEPOSITS
B-1
R-1 20 111 2.2 SM @ 2': Brown fine silty sand, dry to damp, medium dense
551
R-2 24 111.2 6.8 SM-SP @ 5': Dark brown fine silty sand to sand, damp, medium dense
10 46
S-1 22 102.8 8.4 SM-SP @ 10': Reddish brown fine to medium silty sand to sand, damp to moist,
medium dense
15 41
S-2 20 - 5.4 SM-SP @ 15': Grayish brown fine silty sand to sand, damp, medium dense
20 36
S-3 22 - 4.7 SM-SP @ 20': Reddish brown fine to medium silty sand to sand, damp, medium dense
Total Depth: 21.5 feet
No Groudwater was Encountered
25 31
30
BORING NO. B-1
Sheet 1 of 1
APPENDIX B - LABORATORY TESTING PROCEDURES AND RESULTS
Moisture Content and Dry Density
Moisture content was determined for small bulk and relatively undisturbed ring samples. Dry
Density was determined for relatively undisturbed ring samples only. The test procedure is in
accordance with ASTM 2216-90. The results of moisture content and dry density are presented in
the Boring Logs.
Expansion Index
Expansion Index tests were performed using California Building Code Test Method 29-2. The
results of the tests are shown in Table B-1.
Soluble Sulfate Content
Soluble Sulfate Content test was run in accordance with the California Test Methods (CTM) 417.
The test result is shown in Table B-2
Sieve Analyses
Sieve analyses were performed on granular materials in accordance with ASTM D 422. Graphs
showing relationship of the various sizes of soil particles versus percentage passing are shown in
Figure B-1.
TABLE B-1. EXPANSION INDEX TEST RESULTS
Boring Number
Depth (feet)
Soil Description
Expansion
Index
Expansion
Classification
B-1
0-5
Brown Silty Sand
8
Very Low
TABLE B-2. SOLUBLE SULFATE CONTENT
Boring Number
Depth (feet)
Soil Description
Soluble Sulfate
Content (ppm)
B-1
0-5
Brown Silty Sand
126
Sample Depth Percent Passing
(ft) No. 200 Sieve
B-1 S-1 10 12.0 SM-SP
Project Name: Three on Cherry
Project No.: 03-125.7 Figure: B-1
TORO INTERNATIONALGRAIN SIZE DISTRIBUTION CURVE
ASTM D422
Boring No. Sample No. Soil Type
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110100
Particle Diameter in Millimeters
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Sample Depth Friction Angle Cohesion
(ft) (degrees) (psf)
B-1 5 31 0 Peak
29 0 Relaxed
Project Name: Three on Cherry
Project No.: 03-125.7 Figure: B-4
ASTM D3080
ConditionBoring No.
TORO INTERNATIONALDIRECT SHEAR TEST
0
1000
2000
3000
4000
5000
0 1000 2000 3000 4000 5000
NORMAL STRESS (psf)
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Peak
Relaxed
APPENDIX C
DESIGN MAPS SUMMARY
160 Cherry Ave, Carlsbad, CA 92008, USA
Latitude, Longitude: 33.1509344, -117.3467967
Date 9/21/2021, 4:17:39 PM
Design Code Reference Document ASCE7-16
Risk Category II
Site Class D - Stiff Soil
Type Value Description
SS 1.098 MCER ground motion. (for 0.2 second period)
S1 0.396 MCER ground motion. (for 1.0s period)
SMS 1.165 Site-modified spectral acceleration value
SM1 null -See Section 11.4.8 Site-modified spectral acceleration value
SDS 0.777 Numeric seismic design value at 0.2 second SA
SD1 null -See Section 11.4.8 Numeric seismic design value at 1.0 second SA
Type Value Description
SDC null -See Section 11.4.8 Seismic design category
Fa 1.061 Site amplification factor at 0.2 second
Fv null -See Section 11.4.8 Site amplification factor at 1.0 second
PGA 0.486 MCEG peak ground acceleration
FPGA 1.114 Site amplification factor at PGA
PGAM 0.541 Site modified peak ground acceleration
TL 8 Long-period transition period in seconds
SsRT 1.098 Probabilistic risk-targeted ground motion. (0.2 second)
SsUH 1.23 Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration
SsD 1.5 Factored deterministic acceleration value. (0.2 second)
S1RT 0.396 Probabilistic risk-targeted ground motion. (1.0 second)
S1UH 0.438 Factored uniform-hazard (2% probability of exceedance in 50 years) spectral acceleration.
S1D 0.6 Factored deterministic acceleration value. (1.0 second)
PGAd 0.603 Factored deterministic acceleration value. (Peak Ground Acceleration)
CRS 0.892 Mapped value of the risk coefficient at short periods
CR1 0.904 Mapped value of the risk coefficient at a period of 1 s
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APPENDIX D
STANDARD GUIDELINES
for
GRADING PROJECTS
,
2 •
STANDARD GUIDELI:-lES ,OR GRADI:lG r'?.OJECTS
GENERAL
1 • 1 ~epresencacives of the Geocechnical Consultant should
be present on-site during grading operations in order
to make observations and oerform tests so that
professional opinions can.be developed. The opinion
will address whether grading has proceeded in
accordance with the Geotechnical Consultant's
recommendations and applicable project specifications;
if the site soil and geologic conditions are as . . .
. ancic-ipa:ced · · i:n 'the ·"prel i1liiniiry ·'i.hves·c1.g·a:t"{ori";·• 'anl 'if .. , .
additional recommendations are warranted by any
unexpected s ice conditions. Services do not :.nclude
supervision or direction of :~e actual work of :he
concraccor, his employees or agents.
1.2 The guidelines contained herein and the standard
details attached hereto represent this firm's standard
recommendations for grading and ocher associated
operations on construction projects. These guidelines
should be considered a portion of the report to which
they are appended.
1.3 All places attached hereto shall be considered as pare
of these guidelines.
1 .4 The Contractor should not vary from ·chese guidelines
without prior recommendation by the Geocechnical
Consultant and the approval of the Client or his
auchori=ed representative.
1 • 5 7hese Standard Gradin2 Guidelines and Standard Details
ma.y .b.e modi-fied aoo/or superseded bv · i:'eto"milleft'da·tions .
contained in the text of the oreliminarv geocechnical
report and/or subsequent reports. ·
1.6 If disputes arise out of the interpretation of these
grading guidelines or standard details. the Geocech-
nical Consultant shouid deter::iine the appropriate
incerpreca c ion.
DE.FINITIONS OF TERMS
2.1 ALLUVIUM --Unconsolidated detrital deposits resulting
from flow of water, including sediments deposited in
river beds. canyons. ::lood plains. lakes. :ans at the
foot of slopes and estuaries.
Standard Guidelines
for Grading Projects Page 2
2.2
2.J
2.4
.. ... . •'•.
AS-GRADED !AS-BUILT) --,he surface and subsurface
conditions at completion of grading.
BACKCUT --A temporary construction slope at the rear
of earth retaining structures such as buttresses,
shear keys, stabilization fills or retaining walls.
BACKDRAIN --Generally a pipe and ~ravel or similar
drainage system placed behind earth retaining
structures such buttresses, stabilization fills, and
retaining. walls. , ...... , .... · ..... · .•. , .... .-~ ,· ,_. .. : •• •• • •·-<(. • • .,· ........... ~ •..... : •• • .... ••• '• ••
2.5 BEDROCK --A more or less solid. relatively undis-
turbed rock in place either at the surface or beneath
superf~cial deposits of soil.
2.6 BENCH --A relatively level step and near vertical
rise excavated into sloping ground on which fill is to
be placed.
2.7 BORROW (Import) --Any fill material hauled to the
project site from off-site areas.
2.8 BUTTRESS FILL --A fill mass. the configuration of
which is designed by engineering calculations to
retain slope conditions containing adverse geologic
features. A buttress is generally specified by
minimum key width and depth and by maximum backcut
angle. A buttress normally contains a backdrainage
system.
2.9 CIVIL ENGINEER --The Reg{stered Civil Engineer or
cons':11ting firm. respo:7s,~~l~ :_o~--~rE!pa_,r_ati()n_ of -~he · •-.. ,., · ~ra-d:tng•·pla:ns .··-surveying an·d ver1fy1ng as-graded ·
topographic conditions.
2.10 COLLUVIUM --Generally loose deposits usually found
near the base of slopes and brought there chiefly by
gravity through slope continuous downhill cree? (also
see Slope \./ash).
2.11 COMPACTION --Is the densification of a fill by
mechanical means.
2.12 CONTRACTOR --A person or company under contract or
otherwise retained bv the Client :o perform
demolacion, grading ~nd ocher site improvements.
. •: .-... · ... , .. :,
candard Guidelines
or Grading Projects
?age 3
~.13 DEBRIS --All ?roduccs of ciearine, ~rubbing,
demoiition, contaminated soil material unsuicable for
reuse as compacted fill and/or anv other ~acerial so
designated by the Geocechnical Consulcanc.
2.14 ENGINEERING GEOLOGIST --A Geologist holding a valid
certificate of registration in the specialty oc
Engineering Geology.
2.15 ENGINEERED FILL --A fill of which the Geocechnical
Consultant or his represenca_t,.i,".'~, .. c!:U.t:.tl'(g._,g,ri;l~t11.1t,.-_has.
"'' ··niade··suff1i:'i'ent·te~fs c·o··enable him ·co conclude that
the fill has been placed in substantial compliance
with the recommendations of the Geocechnical
Consultant and the governing aeencv reouiremencs.
~.16 EROSION --The wearing awav of the ground surface as a
result of the movement of wind, water, and/or ice.
2.17 EXCAVATION
materials.
The mechanical removal of earth
2.18 EXISTING GRADE --The ground surface configuration
prior co grading.
2.19 FILL --Any deposits of soil, rock, soil-rock blends
or other similar materials placed by man.
2.20 FINISH GRADE --The ground surface configuration at
which time the surface elevations conform co the
approved plan.
2.21 GEOFABRIC --Anv engineering textile utilized in
... , .. ,. ··· --~eotechni.cal· a-p~iica:ciohs ··1ficliidfn'g' 'sub·g·ra:ire·· ... , .. , .
· stabilization and :iltering.
2.22 GEOLOGIST --A representative of the Geocechnical
Consultant educated and trained in the field of
geology.
.......
2.23 GEOTECHNICAL CONSULTANT --The Geotechnical Engineer-
ing and Engineering Geology consulting firm retained
co provide technical services for the pro.i ect. For
the purpose of these guidelines, observations by the
Geotechnical Consultant include observations by the
Geotechnical Engineer, Engineering Geologist and those
performed by persons employed by and responsible to
the Geotechnical Consultants.
·•: . . . . . ·.• . .
Standard Guidelines
for Grading Projects Page 4
2.24 GEOTECHNICAL ENGINEER --A licensed Civil Engineer who
applies scientific methods, engineering principles and
professional experience co the acquisition, :.nter-
pretation and use of knowledge of materials of the
earth's crust for che evaluation of engineering
problems. Geotechnical Engineering encompasses many
of the engineering asoects of soil rnechanics, rock
mechanics, geology, geophysics, hydrology and related
sciences .
. 2. 25 ... , GRAP.IN~ .. --: . .A\1.Y _9_P,.e:r2;_t iqn .. cor,s i st.ini; .. of exc_a.lla t ion., ..
• ·· ftll[ng ~r··cojbinations thereof and associated
operations.
2.26 LANDSLIDE DEBRIS --(-!aterial, generally porous and of
low density, produced :rom instability or natural of
man-made slopes.
2.27 MAXIMUM DENSITY --Standard laboratory test for
maximum dry unit weight. Unless otherwise specified,
the maximum dry unit weight shall be determined in
accordance with ASTM Method of Test D1557.
2.28 OPTIMUM MOISTURE --Test moisture content at the
maximum density.
2.29 RELATIVE COMPACTION --The degree of compaction
(expressed as a percentage) of dry unit weight of a
material as compared to the maximum dry unit weight of
the material.
2.30 ROUGH GRADE --The ~round surface configuration at
which time the surface elevations. aoproximateLv_. •· '.·· ·-·· .. · conform· ta th~··app'i:'ovea .plan;·· .... ·•• .... ·· -: , ... -..... -
2. 31 SITE --The oarticular parcel or land where grading is
being performed.
2.32 SHEAR KEY --Similar to buttress, however, it is
generally constructed bv excavating a slot within a
natural slope in order co stabilize the upper ?Ortion
of the slope without grading encroaching into the
lower 7ortion of the slope.
2.33 SLOPE --Is an inclined ground surface the steepness
of which is generally soecified as a ratio of
hori::ontal:vertical (e.g., 2: 1).
2.34 SLOPE wASH --Soil and/or rock material chat has been
transported down a slope by mass wasting assisted by
runoff water not confined by channels (also see Colluvium).
canciarw Guideii~es
or Gracing ?rejects ?age 5
2.35
2.36
2.37
·: .. · -.-: :-
~OIL --Nacurallv occurring deoosi:s of sand, 5ilt,
clay, etc., or combinations chereof.
SOIL ENGINEER --Licensed Civil Engineer exoerienced
in soil mechanics (also see Geocechnical Engineer).
STABILIZATION FILL --A fill mass, the configuration
of which is typically related co slope height and is
specified by the standards of practice for enhancing
the stability of locally adverse conditions. A
stabilization_ fill ~s. l)Ormally.s.peci_f~_ed . .t,y m,ini.mum ·· •. ,
~k'ey'w{citfi ·and°·depcn ·and by max.imum· backcuc angle. A
stabilization fill may or may not have a backdrainage
system specified.
2.38 3UBDRAIN --Generally a pipe and gravel or similar
drainage system placed beneath a fill in the alig~menc
of canyons or former drainage channels.
2.39 SLOUGH --Loose, noncompacced fill material generated
during grading operations.
2.40 TAILINGS --Nonengineered fill which accumulates on or
adjacent co equipment haul-roads.
2.41 TERRACE --Relatively level seep constructed in the
face of graded slope surface for drainage control and
maintenance purposes.
2.42 TOPSOIL --The presumably fertile.upper zone of soil
which is usuall~ darker in color and loose.
2.43 ~INDROW --A sering of large rock buried_wich~n.
., ... -·eng·i:neered· fi•ll •i·n •·a:ctcrdanc·e·';;Tcn'·gui.del'iries ·sec·
forth by the Geotechnical Consultant.
3. SITE PREPARATION
. ... ,
3.1 Clearing and grubbing should consist of the removal of
vegetation such as brush, grass, woods, stumps, trees,
roots co trees and otherwise deleterious natural
materials from the areas co be graded. Clearing and
~rubbing should extend co the outside of all proposed
excavation and fill areas.
3.2 Demolition should include removal of buildings, struc-
tures, foundations, reservoirs, utilities ( including
underground pipelines, septic tanks, leach fields,
seepage pits, cisterns, mining shafts, tunnels, etc.)
and other man-made surface and subsurface improvements
Standard Guidelines
Ear Grading Projects Page 6
from the areas co be graded. ,emolicion of utilities
should include proper canping and/or re-routing pipe-
lines at the project perimeter and cutoff and capping
of wells in accordance with che requirements of the
governing authorities and the recommendations of the
Geocechnical Consultant at the time of demolition.
3.3 Debris generated during clearing, grubbing and/or
demolition operations should be wasted from areas co
be graded and disposed off-site. Clearing, grubbing
.. and __ ~emol_ici9r1 _o_pe;-_~c;o_ns_ ~h.o,ulq,~~ P.e_rf9.i:i11ed_ •. uJ1der.. .,
· · ·tne··obs·erv'"aciori· of the Geocechnical Consulcanc.
SITE PROTECTION
4.1 The Contractor should be responsible for the stability
of all temporary excavations. Recommendations by the
Geotechnical Consultant pertaining co temporary
excavations (e.g., backcucs) are made in consideration
of stability of the completed project and, therefore,
should not be considered co preclude the responsibil-
ities of the Contractor. Recommendations by the
Geotechnical Consultant should not be considered to
preclude more restrictive requirements by the
regulating agencies.
4.2 Precautions should be taken during the performance of
site clearing, excavations and grading co protect the
work site from flooding, ponding or inundation by poor
or improper surface drainage. T~mporary provisions
should be made during the rainv ~eason co adequately
· direct surface draina·ge away :'~om ·and off the work
site.
. .,, .. .,. .... . .. ·: ........ :•· .... .
4 • 3 During ?eriods of rainfall, the Geocechnical
Consultant should be kept informed by the Contractor
as co the nature of remedial or preventative work
being performed (e.g., pumping, placement of sandbags
or plastic sheeting, ocher labor, dozing, ecc.).
4.4 . Following periods of rainfall, che Contractor should
contact the Geocechnical Consultant and arrange a
review of ·the site in order co visually astess rain
related damage. The Geocechnical Cons~lcanc may also
recommend excavations and testing in order co aid in
his assessments.
4.5 Rain related damage should be considered co include,
but may not be limited to, erosion, silting,
saturation, swelling, structural distress and ocher
adverse conditions identified by the Geocechnical
Standard Guidelines
for Grading Projects '?age 7
Consultant. Soil adverselv aifecced should be
classified as Unsuitable Materials and should be
subject co overexcavacion anci replacement with
compacted fill or ocher remedial grading as
recommended by the Geocechnical Consultant.
5. EXCAVATIONS
5.1 UNSUITABLE MATERIALS
5 • 1 • 1
.. ••· ... :., .. ,
5. 1 • 2
Mace rials, which ar.e .. u_ns,'4,i. t;:abl.e s.hoµld ._.b_e _ ...
.. excav·afed 'i.111a·er. obs:ervac1011 and recommendations
of the Geotechnical Consultant. Unsuitable
materials include, but may not be limited co,
dry, loose, soft. wet. organic compressible
natural soils and fractured, weathered, ~oft
bedrock and nonengineered or otherwise
deleterious fill materials.
Material identified by the Geotechnical
Consultant as unsatisfactory due to its
moisture conditions should be overexcavaced,
watered or dried, as needed, and thoroughly
blended to a uniform near optimum moisture
condition (as per guidelines reference 7.2.1)
prior co placement as compacted fill.
5. 2 CUT SLOPES
s.2.1
5. 2 _ 2
5.2.J
Unless otherwise recommended by the G~otech-
nical Consultant and approved by tqc_reg~lating
agenci·es, ?erma·nenc cue ·slopes should no c :ie
steeper :San 2: 1 (horizoncal:vercical).
. . . ,.,,, •· ; r: .· ' .. • •. ·• . . -·. . •· • ·• ~ . ,... ' ., • • . ·., .• _.,_ •·
If excavations :or cut slopes expose loose,
cohesionless, significantly fractured or
otherwise unsuitable material, overexcavation
and replacement of the unsuitable materials
with a compacted stabilization fill should be
accomplished as recommended by the Geocechnical
Consultant. Unless otherwise specified by the
Geotechnical Consultant, stabilization fill
construction· should c·onforn co the requirements
of the Standard Details.
The Geocechnical Consultant should review cut
slopes during excavation. The Geotechnical
Consultant should be notified by the contractor
prior to beginning slope excavations.
Stanoarc Guidelines
for Grading Projects Page 8
5.2.~ !f, juring the course of grading, 3dverse or
potenciaily adverse geocechnical conditions are
encountered which were not anticipated in the
preliminary report, :he Geocechnical Consultant
should explore, analyze and make recommen-
dations to creac these problems.
6. COMPACTED FILL
i ·. -.. • ·.
All fill materials should be compacted co ac lease 90
percent of max~mum qen~_ity_ ,\A\>'):'lf,D.1 S;i}) .unless .. o?he.rwise ... · ...
·tecorhmerided by" ·che··ceotechnical Consultant.
6. 1 PLACEMENT
... ,.
6. 1 .1 Prior to placement of compacted fill, che
Contractor should request a review by the
Geocechnical Consultant of the exposed ground
surface. Unless otherwise recommended, the
exposed ground surface should then be scarified
(6-inches minimum), watered or dried as needed,
thoroughly blended to achieve near optimum
moisture conditions, then thoroughly compacted
to a minimum of 90 percent of the maximum
density,
6.1 .2 Compacted fill should be placed in thin
horizontal lifts. Each lift should be watered
or dried as needed, blended co achieve near
optimum moisture conditions then compacted by
mechanical methods to a minimum _of 90 percent
of laboratory maximum dry densitv. C:ach lift
should be treated in a like manner until t~~
• • ' • . .. • • J· . • ••• • • •• • • -... _ ., • • .• .. • •• • •• •• ·-ct·esiI'ed f1r!1sh·ect grades are achlevea .
6.1 .J When placing fill in horizontal lifts adjacent
to areas sloping steeper than 5:1 (horizontal:
vertical), horizontal keys and vertical benches
should be excavated into the adjacent slope
area. Keying and benching should be sufficient
to provide ac least 6-fooc wide benches and a
minimum of ~-feet of vertical bench height
within the firm natural ground, firm bedrock or
engineered compacted fill. No compacted fill
should be placed in an area subsequent co
keying and benching until the area has been
reviewed by the Geocechnical Consultant.
Material generated by the benching operation
should be moved sufficiently away from the
bench area co allow for the recommended review
of the horizontal bench prior to placement
.. :•
-. ·-··
··•-: , ..
canaara Guidelines
or Grading Projects
?age 9
6. 1 • 4
fill. Typical ~eying and benching details have
been included within :~e accompanying Standard
Details.
Within a single fill area where graa1ng
procedures dictate two or more separate fills,
temporary slopes (false slopes) may be created.
When placing fill adjacent to a false slope,
benching should be conducted in the same manner
as above described. At least a 3-fooc vertical
bench should be established within the firm
core .adj.acenc ..appr.o.ved -.compac-ted, fi·ll"p-rior·'·co··· · ·.· ... · •
placement of additional fill. Benching should
proceed in at least 3-foot vertical increments
until the desired finished grades are achieved.
6.1.5 Fill should be tested for compliance with the
recommended relative compaction and moisture
conditions. Field density testing should
conform co accepted test methods. Density
testing frequency should be adequate for the
geotechnical consultant to provide professional
opinions regardings fill compaction and
adherence to recommendations. Fill found not
co be in conformance with the grading
recommendation should be removed or otherwise
handled as recommended by the Geotechnical
Consultant.
6.1 .6 The Contractor should assist the Geotechnical
Consultant and/or his representative bv digging
test pits for removal decer-minations ~nd/or for
testing compacted fill.
As ·re-c~mm~~-ded i',; ···the Geo technical ··c~~-sui~;~t,
the Contractor may need co remove grading
equipment from an area being tested if
personnel safety is considered to be a problem.
6.2 MOISTURE
6.2.1 For field testing purposes "near optimum"
moisture will vary with mat~rial type and other
factors including compaction procedure. "Near
optimum" may be specifically recommended in
Preliminary Investigation Reports and/or may be
evaluated during grading.
6.2.2 Prior to placement of additional compacted fill
following an overnight or ocher grading delay,
the exposed surface or previously compacted
. ... ;..: .
· .. · ....
Stanaard Guidelines
for Grading Proieccs Page 10
6.2.3
fill should be processed bv scarification,
watered or dried as needed, choroughlv blended
co near-optimum moisture conditions, ~hen
recompacted to a minimum of 90 percent of
laboratory maximum dry density. \Jhere wee,
dry, or other unsuitable materials exist to
depths of greater than one foot, che unsuitable
materials should be overexcavated.
Following a period of flooding, rainfall or
overwatering by ocher means, no additional fill
.should-.he, placed. unc-i-1 · damage ·ass!!ssn\en·t·s· have .
been made and remedial grading performed as
described under Section 5.6 herein.
A.3 :'ILL :'ATERIAL
6.3.1 Excavated on-site materials which are
considered suitable to the Geocechnical
Consultant mav be utilized as compacted fill,
provided trash, vegetation and other
deleterious materials are removed prior to
placement.
6.3.2 Where import fill materials are required for
use on-site, the Geo technical Consultant should
be notified in advance of importing, in order
to sample and test materials from proposed
borrow sites. No import fill materials should
be delivered for use on-site without prior
sampling and cescing notification bv
Geotechnical Consultant ..
6.3.3 .... , ........ •'•'
'-v'here oversized rock-. or .. s.i111iJ,ar-Lr--r-eduei-ble -
mai:e-r"ia"i Ls generated during grading' it is
recommended, where practical, co waste such
material off-site or on-site in areas
designated as "nonstructural rock disposal
areas''. Rock placed in disposal areas should
be placed with sufficient fines to fill
voids. The rock should be compacted in lifts
to an unyielding condition. The disposal area
should be cove,ed with at least three feet of•
compacted fill which is free of oversized
material. The upper three feet should be
placed in accordance with the guidelines for
compacted fill herein.
6.3.4 Rocks 12 inches in maximum dimension and
smaller may be utilized within the compacted
fill, provided they are placed in such a manner
.. ·•··'
...•
3tanaard Guidelines
for Grading Projects Page 11
6. 3. 5
, ... · ....... ,
that nescing of che rock is avoided. Fill
should be placed and thoroughly compacted over
and around all rock. The amount of rock should
not exceed 40 percent by ary weight retained on
the 3/4-inch sieve size. The i2-inch and 40
percent recommendations herein may vary as
field conditions dictate.
Where rocks or similar irreducible materials of
greater than 12 inches but less than four feet
of maximum dimension are generated during
..... grad ii.~ •.. or. .-otherw.i.se-.desir.ed. ,to· he ·p 1-aced·. · •·· .·
within an engineered fill, special handling in
accordance with the accompanying Standard
Details is recommended. Rocks greater than
four feet should be broken down or disposed
off-site. Rocks up to four feet maximum
dimension should be placed below the upper 10
feet of any fill and should not be closer than
20-feet co any slope face. These recommen-
dations could vary as locations of improvements
dictate. Where practical, oversized material
should not be placed below areas where
structures or deep utilities are proposed.
Oversized material should be placed in windrows
on a clean, over.excavated or unyielding
compacted fill or firm natural ground surface.
Select native or imported granular soil (S.E.
30 or higher) should be placed and thoroughly
flooded over and around all windrowed rock,
such that voids are filled. ~indrows of
oversized material should be staggered so ch•c
successive strata of oversized material are not
in the same ver.cical p.l_ane.. ...... : .. •. . . . ..... , ... .-.. ~ ....... ,, .. ".; ,, ......... .
6.3.5 le may be possible co dispose of individual
larger rock as field conditions dictate and as
recommended by the Geotechnical Consultant ac
the time of placement.
6.3. 7 The construction of a "rock fill" consisting
primarily of rock fragments up co two feet in
maximum dimension with little soil material may
be feas'ible. Such material is typically
generated on sites where extensive blasting is
required. Recommendations for conscruccion of
rock fills should be provided by the
Geocechnical Consultant on a site-specific
basis.
,candard Guidelines
:or Gracing Projects Page I 2
·•· ..
6 • 3 • 8
.· ....... .
6.3.9
Juring graa1ng ooerations, ?lacing and mixing
che materials fr~m the cue and/or borrow areas
may result in soil mixtures which possess
unique physical ?ropercies. Testing may be
required of samples obtained directlv from the
fill areas in order co determine conformance
with the specifications. Processing of these
additional samples may take two or more working
days. The Contractor may elect co move the
operation co other areas within the project, or
may continue placing compacted fill pending
laboratorv and field test results. Should he
'"elect.the·.se.cond-alcernatiV!!, 'fill pla·ced ts'··
done so ac the Contractor's risk.
Any fill placed in areas not previously
reviewed and evaluated bv the Geocechnical
Consultant may require removal and recom-
paction. Determination of overexcavations
should be made upon review of field conditions
by the Geotechnical Consultant.
6.4 FILL SLOPES
6.4.1 Permanent fill slopes should not be constructed
steeper than 2: 1 (horizontal to vertical),
unless otherwise recommended by the Geotech-
nical Consultant and approved by the regulating
agencies.
6. 4. 2
.....
Fill slopes should be compacted in accordance
with these grading guidelines and specific
report recommendations. Two methods or slope
compaction are cvpically utilized in mass
g_ ~!ld i !1!'., . lat er .a 1. .i;,:ve.r ·:!:mi 1-di ng _.and· cus: t: i ng -b-a-clc ,
ancf mechanical compaction co g·rade (i.e.
sheepsfooc roller backrolling). Constraints
such as height of slope, fill soil type, access,
property lines, and available equipment will
influence the method of slope construction and
compaction. The geotechnical consultant should
be notified by the contractor what method will.
be employed prior to slope construction.
Slopes utilizing over-building and cutting back
should be constructed utilizing horizontal fill
lifts (reference Section 6) with compaction
equipment working as close to the edge as prac-
tical. The amount of lateral over-building will
varv as field conditions dictiate. Compaction
testing of slope faces will be required and
Stanaara Guidelines
for Grading Projects ?age 1 3
reconstruction of the slope ~ay result .•
testing does r.ot ~eet our recommendations.
Mechanical compaction of the slope co grade
during constru~tion should utilize cwo types of
compactive effort. First, horizontal fill lifts
should be compacted during fill placement. This
equipment should provide compactive effort to
the outer edge of the fill slope. Sloughing of
fill soils should not be permitted to drift down
the slope. Secondly, at intervals not exceeding
-four.-feet. i.n vertical-slope he-ighc ·or ch·e· ·. ·· • ..
capability of available equipment, whichever is
less, fill slopes should be backrolled with a
sheepsfoot-type roller. Moisture conditions of
the slope fill soils should be maintained
throughout the compaction process. Generally
upon slope completion, the entire slope should
be compacted utilizing typical methods, (i.e.
sheepsfoot rolling, bulldozer tracking, or
rolling with rubber-tired heavy equipment).
Slope construction grade staking should be
removed as soon as possible in the slope
compaction process. Final slope compaction
should be performed without grade sakes on the
slope face.
In order to monitor slope construction
procedures, moisture and density tests will be
taken at regular intervals. Failure to achieve
the desired results will likelv result in a
recommendation bv the Geotechnical Consultant
to overexcavate ~he slope surfaces ·followed hy
.r:.eq,i:is.tr1;1_ct_ion. o.f ,th~ .slopei. ut:il,i:z.ing -over~--......... ·· ·
filling and cutting back procedures or further
compactive effort with the conventional
backrolling approach. Other recommendations
may also be provided which would be
commensurate with field conditions.
6.4.3 Where placement of fill above a natural slope
or above a cut slope is proposed, the fill
slope configuration as presented in the
accompanying Standard Details should be
adopted.
6.4.4 For pad areas above fill slopes, ?Ositive
drainage should be established away from the
top-of-slope, as designed by the project civil
engineer.
... '·.
Standard Guidelines
for Grading Projects ?age 14
.... ·
A.5 OFF-SITE FILL
6.5.1 Off-site fill should be created in the same
manner as recommended in the specifications for
site preparation, excavation, drains,
compaction, etc.
6.5.2 Off-site canyon fill should be placed in
preparation for future additional fill, as
shown in the accompanying Standard Details •
. 6 •. 5. 3 Off-si.te. fill ·subdrai-ns· cemporar·ily cenrrinated···
(up canyon) should be surveyed for future
relocation and connection.
~.6 TRENCH BACKFILL
6.6.1 Ucilicv trench backfill should, unless other-
wise recommended, be compacted by mechanical
means. Unless otherwise recommended, the
degree of compaction should be a minimum of 90
percent of maximum density (ASTM D1557).
6.6.2 Backfill of exterior and interior trenches
extending below a 1:1 projection from the outer
edge of ·foundations should be mechanically
compacted co a minimum of 90 percent of the
laboratory maximum density.
6.6.3 ~ithin slab areas, but outside the influence of
foundations, trenches uo co one foot wide and
-two feet deeo mav be ba~kfilled with sand• (S.E .. > 30), and consolidated by jetting, .:loading or
.. _by .mt;!\:h.apical means ... ·it. or,-_s..ic.e .mac-eri..als ,are .. · ·
·· tltilized, ·c~ey should be wheel-rolled, camped
or otherwise compacted co a firm condition.
For minor interior trenches, densicv testing
may be deleted or spot testing may be elected
if deemed necessary, based on review of
backfill operations during construction.
6.6.4 If utility contractors indicate chat it is
undesirable co use compaction equipment in
close proximity co a buried conduit, the
Contractor mav elect che utilization of light
weight mechanical compaction equipment and/or
shading of the conduit with clean, granular
material, (S.E. > 30) which should be
thoroughly moistened in the trench, prior co
3canaard Guideiines
for Grading Projects
Page 15
:niciacing mechanical oomoaccion orocedures.
Other methods of ucilicv ~rench·comoaccion mav
also be appropriate, upon review of° the
Geocechnical Consulcanc ac :he cirne of
conscruccion.
n.6.5 In cases where clean granuiar materials are
proposed for ~se in lieu of native materials or
where flooding or jetting is proposed, che
procedures should be considered subject co
review by che Geocechnical Consulcanc •
6. 6. 6
·-. ~. .. . •
Clean granular backfill and/or bedding are nee
recommended in slope areas unless provisions
are made for a drainage svscem co micigace the
pocencial build-up of s2e~age ~orces Rnd
piping.
7. DRAINAGE
8 •
7.1 Canyon subdrain systems recommended by che
Geotechnical Consultant should be installed in
accordance with the Standard Details.
7.2 Typical subdrains for compacted fill buttresses, slope
stabilizations.or sidehill masses, should be installed
in accordance with che specifications of che
accompanying Standard Details.
7.3 Roof, pad and slope drainage should be directed awav
from slopes and areas of scruccures co disoosal areas
via suitable devices designed bv che proiecc civil
engineer ,:i.e., guccers, ::ownspoucs, concrete swales,
area drains, eai;-ch swales, ~tc .•. i.,_ .. , .. · ... , ••. . . . . . . . ... , .
7.4 Drainage oaccerns established cc :he cime ot tine
grading should be maintained chroughouc che life of
the project. Property owners should be made aware
chat altering drainage paccerns can be decrimencal co
slope scabilicy and foundation performance.
SLOPE ~INTENANCE
8.1 LANDSCAPE PLANTS
In order co decrease erosion surficial slope stability
problems, slope planting should be accomplished ac che
completion of grading. Slope planting should consist
of deep-rooting vegecacion requiring liccle watering.
A Landscape Archicecc would he che cest parcy co
consult regarding actual cypes or planes and planting
configuration.
. •,• ..
Stan □ard Guidelines
Eor Grading Projects
?age I 6
8.2 IRRIGATION
. . .. .. .
8.2.1 Slope irrigation should be minimized. If
automatic timing devices are utilized on
irrigation systems, ?rovisions should be made
for interrupting normal irrigation during
periods of rainfall.
8.2.2 Propert:, owners should be made aware that
. overwatering .of s-lopes is detrimental tcr slope
stability and may contribute to slope seepage,
erosion and siltation problems in the
subdivision.
. , ./• . , ··,l •• •.. . ... ,· '• ...
4• DIAMETER PERFORATED--
PIPE BAC.<ORAIN
4• DIAMETER NON-PERFORATEO-
PIPE LATERAL DRAIN
SLOPE PER PLAN
MIN.1
15' MINIMUM--
aENCHING
H/2
PROVIDE BACKDRAIN PER BACK DRAIN
DETAIL. AN ADDITIONAL BACKDRAIN
AT MIO-SLOPE WILL BE REQUIRED FOR
SLOPE IN EXCESS OF 40 FEET HIGH •
. I\E.!.-?l"!E.NSIOt,ISPER SOILS ENG.11116.ER ,,. . ..... ·-· ., ....
TYPICAL BUTTRESS OR ST ABIUZA TION FILL DETAIL
JOB NO.: DATE: FIGURE:
1
JOB NO.:
NATURAL GROUND
PROVIDE BACKDRAIN PER
BACKDRAIN DETAIL. AN
ADDITIONAL BACKDRAIN
AT MID-SLOPE WILL BE
REQUIRED FOR BACK
SLOPES IN EXCESS OF
COMPACTED FILL
PROPOSED GRADING
1
BASE WIDTH •w• DETERMINED
BY SOILS ENGINEER 40 FEET HIGH. LOCA-
TIONS-OF BACKDRAINS
AND OUTLETS PER SOILS
ENGINEER AND/OR EN-
(ilNEERiN(f GEOLOGIST·· ...
DURING GRADING.
. .... • ....
TYPICAL SHEAR KEY DETAIL
FIGURE;
2
' . .
JOB NO.:
FINAL LIMIT OF
EXCAVATION
2' MINIMUM
DAYLIGHT
LINE
OVERBURDEN
(CREEP-PRONE)
OVER EXCAVATE
FINISH PAD~
OVER EXCAVATE
3' ANO REPLACE
WITH COMPACTED
FILL
SOUND BEDROCK
TYPICAL BENCHING
----
PROVIDE BACKDRAIN PER BACKDRAIN
DETAIL. LOCATION OF BACKDRAIN ANO
-OUTLETS .. PER.6011.S. E_NGJNEER AND/OR
ENGINEERING GEOLOGIST DURING
GRADING
EQUIPMENT WIDTH (MINIMUM 15')
DAYLIGHT SHEAR KEY DETAIL
IDATE: FIGURE:
JOB NO.:
1
BENCHING FILL OVER NATURAL
FILL SLOPE-
\ -r
SURFACE OF FIRM--
EARTH MATERIAL
\_10' MIN. (INCLINEO 2'1. MIN. INTO SLOPE)
BENCHING FILL OVER CUT
FINISH FILL SLOPE
SURFACE OF FIRM
EARTH MATERIAL
FINISH CUT
SLOPE
10·
TYPICAL
15' MIN. OR STABILITY EQUIVALENT PER SOIL
ENGINEERING (INCLINED 2'1. MIN. INTO SLOPE)
BENCHING FOR COMPACTED FILL DETAIL
DATE: IFIGURE:
----
FINISH SURFACE SLOPE--.
3 FT3 MINIMUM PER LINEAL FOOT--
APPROVED FILTER ROCK'
I
2 'I, MINIM~~ GRADIENT
COMPACTED FILL
.· ..... . . ·. ·. . ..
I \ :
\_4• MINIMUM APPROVED
PERFORATED PIPE**
(PERFORATIONS DOWN)
MINIMUM 21' GRADIENT
TO OUTLET
BENCH INCLINED TOWARD
DRAIN
,4• MINIMUM DIAMETER
SOLID OUTLET PIPE
SPACED PER SOIL
ENGINEER REQUIRE-
MENTS DURING GRADING TYPICAL BENCHING
DETAIL A-A
I
COMPACTED
BACKFILL
TEMPORARY FILL LEVEL
,4• MINIMUM DIAMETER
APPROVED SOLID
OUTLET PIPE
. . ..
12" MINIMUM~ *FILTER ROCK TO MEET FOLLOWING
SPECIFICATIONS OR APPROVED EOUAL:
**APPROVED PIPE TYPE:
SCHEDULE 40 POLYVINYL CHLORIDE
(P.V.C.) OR APPROVED EOUAL.
MINIMUM CRUSH STRENGTH 1000 PSI.
SIEVE
1•
3/4"
3/8"
N0.4
N0.30
NO.SO
N0.200
TYPICAL BACKDRAIN DETAIL
JOB NO.: DATE:
PERCENTAGE PASSING
100
80-100
40-100
25--40
5-15
0-7
0-3
FIGURE:
FINISH SURFACE SLOPE -
MINIMUM 3 FT3 PER LINEAL FOOT -
OPEN GRADED AGGREGATE~
TAPE ANO SEAL AT CONTACT --
JOB NO.:
A
4• MINIMUM DIAMETER
SOLID OUTLET PIPE
SPACED PER SOIL
ENGINEER REQUIREMENTS
COMPACTED FILL
TYPICAL
BENCHING
DETAIL A-A
COMPACTED
SUPAC 8-P FABRIC OR
APPROVED EQUAL
4• MINIMUM APPROVED
PERFORATED PIPE
(PERFORATIONS DOWN)
MINIMUM 2'!. GRADIENT
TO OUTLET
BENCH INCLINED
TOWARD DRAIN
TEMPORARY FILL LEVEL
MINIMUM BACKFILL MINIMUM 4• DIAMETER APPROVED
SOLID OUTLET PIPE 12• COVER
J_
Jl-,2•--l 1 MINIMUM 'I
* NOTE: AGGREGATE TO MEET FOLLOWING
SPECIFICATIONS OR APPROVED EOUAL:
SIEVE SIZE
1 112·
1•
3/ ".
3/8"
NO. 200
PERCENTAGE PASSING
100
5--40
0-17
0-7
0-3
BACKDRAIN DETAIL (GEOFABRIC)
DATE: FIG.JAE:
6
CANYON SUBDRAIN DETAILS
TYPICAL BENCHING-
INCLINE TOWARD DRAIN
SEE DETAILS BELOW
TRENCH DETAIL
e• MINIMUM OVER LAP --li-'-'-''--~-~"""-==,T--
OPTIONAL V-DITCH DETAIL MINIMUM 6 FT 3 PER LINEAL
FOOT OF APPROVED DRAIN
MATERIAL
SUPAC 8-P FABRIC
OR APPROVED EQUAL
JOB NO.:
l, 2,· l 1 MINIMUM/
6UPAC 5-P FABRIC OR
APPROVED EQUAL
DRAIN MATERIAL SHOULD
CONSIST OF MINUS 1.5",
MINUS t•, OR MINUS .75"
CRUSHED ROCK
MINIMUM 6 FT 3 PER LINEAL FOOT
OF APPROVED DRAIN MATERIAL
ADD MINIMUM 4• DIAMETER
APPROVED PERFORATED
PIPE WHEN LARGE FLOWS
ARE ANTICIPATED
APPROVED PIPE TO BE
SCHEDULE 40 POLY-VINYL-
CHLORIDE (P.V.C.l OR
APPROVED EQUAL. MINIMUM
CRUSH STRENGTH 1000 psi.
GEOFABRIC SUBDRAIN
DATE:
FINAL GRADE
TOE OF SLOPE SHOWN
ON GRADING PLAN
FILL --------
---0"1,.0) -:-_,,,,. ,,,.1:.~ ---'-~ .....-\.." --,,,,,,,,.........-~p.\,.. .,,,,....--
------~,.. i --
--~l'-i" -----1:.~ _,,,,.
------e,1..I:. -----\l Ii ,-. _.,...:::-------,-......,----------' ,,-\)~S _,,,,. 10• TYPICAL BENCH ;,--_,,,,.
~----'-----------,,~ .-WIDTH VAR IE 6
_,,,,. --~ ~-/ ---
FILL ,,-,,-~ ~ _.dt _,,..-_,,,,.__.
----/1 __ .....-.,,,,.... COMPETENT EARTH
MATERIAL --------
------
MINIMUM
DOWNSLOPE
KEY DEPTH
I
LIMIT OF KEY
EXCAVATION
JOB NO.:
MINIMUM BASE KEY WIDTH I
TYPICAL BENCH
HEIGHT
;:>ROYIDE BACKDRAIN AS
REQUIRED PER RECOM-
MENDATIONS OF SOILS
ENGINEER DURING GRADING
WHERE NATURAL SLOPE GRADIENT IS 5: 1 OR LESS.
BENCHING IS NOT NECESSARY. HOWEVER. FILL IS
NOT TO BE PLACED ON COMPRESSIBLE OR UNSUIT-
ABLE MATERIAL.
FILL SLOPE ABOVE NATURAL GROUND DETAIL
!FIGURE: S
REMOVE ALL TOPSOIL, COLLUVIUM
ANO CREEP MATERIAL FROM
TRAllSI TION
CUT/FILL CONTACT StlOWN
ON GRADING PLAN
CUT/FILL CONTACT SHOWN
ON •AS-BUILT"
NATURAL~ ----TOPOGRAPHY -----------------------. ----CUT SLOPE
FILL ------------,._...,..,.,,,,., ---
----.,o-iE-..---___ ,,_ ... f'\:.ff' ·----
--.--f' \:. \:. V .,-------tl O C -..--'q.._--______ J
----l-A,.. ------;o\.l.-\l'l~--------4' TYPICAL j
--.---' 13,0 \ \... _,.....::--__ --_______ _J
---/ ~--_;~"..----~-'10' TYPICAL-
----1 ~--~ ... "'"'"""-f BEDROCK OR APPROVED
FOUNDATION MATERIAL
• NOTE: CUT SLOPE PORTION SHALL BE MADE
PRIOR TO PLACEMENT OF FILL
FILL SLOPE ABOVE CUT SLOPE DETAIL
JOB NO.: DATE: FIGURE:
l:!
-------
---------------
GENERAL GRADING RECOMMENDATIONS
---
CUT LOT
----ORIGINAL
-GROUND ----------------TOPSOIL, COLLUVIUM AND _... ..-
WEATHERED BEDROCK ___ _..._...
------------
------
3'
OVEREXCAVATE AND
REGRADE UNWEATHERED BEDROCK
CUT/FILL LOT (TRANSITION)
---------------------
------
_... ORIGINAL ___ _.,.,,,-GROUND
----------------
COMPACTED FILL
UNWEATHERED BEDROCK
TRANSITION LOT DETAIL
JOB NO.:
OVEREXCAVATE AND
REGRADE
FIGURE:
10
FINISHED GRADE
r CLEAR AREA FOR
FOUNDATION, UTILITIES,
AND SWIMMING POOLS
f----'-,--s--0 0
0 0 , O T 1l,
, 5. 0 1,
BUILDING
, o·
SLOPE FACE ,
STREET-
,
\_WINDROW ~------~----
5' OR BELOW DEPTH OF __j
/
JOB NO.:
DEEPEST UTILITY TRENCH
(WHICHEVER GREATER)
TYPICAL WINDROW DETAIL (EDGE VIEW)
: :·
, .. . .. .... . · .. :-.
/
..
/
GRANULAR SOIL FLOODED
TO FILL VOIDS
HORIZONTALLY PLACED
COMPACTION FILL
/ /
PROFILE VIEW
/
ROCK DISPOSAL DETAIL
DATE: I FIGURE:
11·
GEOTECHNICAL INVESTIGATION
for
MULTI-FAMILY BUILDING
THREE ON CHERRY
160 CHERRY AVENUE
CARLSBAD, CALIFORNIA
Prepared For:
DI DONATO ASSOCIATES
3939 FIRST AVENUE, SUITE 100
SAN DIEGO, CALIFORNIA 92103
Prepared By:
TORO INTERNATIONAL
1 LEAGUE # 61614
IRVINE, CA 92602
October 26, 2018
October 26, 2018
TI Project No. 03-125.7
Di Donato Associates
3939 First Avenue, Suite 100
San Diego, California 92103
Subject: Preliminary Geotechnical Investigation for Proposed Multi-Family Building, Three
on Cherry, 160 Cherry Avenue, Carlsbad, California
Toro International (TI) has completed preliminary geotechnical investigation for a proposed Multi-
Family Building, Three on Cherry, 160 Cherry Avenue, Carlsbad, California. This report presents
our findings, conclusions and recommendations for foundation design and construction of the
proposed multi-family building and its associated site preparation.
It is our opinion from a geotechnical viewpoint that the subject site is suitable for construction of the
proposed multi-family building provided our geotechnical recommendations presented in this report
are implemented in the design and during construction.
The recommendations developed in this report are based on empirical and analytical methods typical
of the standard of practice in California. We appreciate this opportunity to be of service.
Sincerely,
TORO INTERNATIONAL
Hantoro Walujono, GE 2164
Principal
EXP. 3/31/19
TABLE OF CONTENTS
1.0 INTRODUCTION ...............................................................................................................1
1.1 General.....................................................................................................................1
1.2 Proposed Development............................................................................................1
1.3 Site Description........................................................................................................1
1.4 Scope of Work .........................................................................................................3
2.0 FIELD EXPLORATION AND LABORATORY TESTING..............................................4
2.1 Field Exploration .....................................................................................................4
2.2 Laboratory Testing...................................................................................................4
3.0 SITE CONDITIONS............................................................................................................6
3.1 Geology....................................................................................................................6
3.2 Groundwater ............................................................................................................6
3.3 General Subsurface Conditions ...............................................................................6
4.0 SEISMICITY.......................................................................................................................7
4.1 General.....................................................................................................................7
4.2 Ground Motion ........................................................................................................7
4.3 Seismic Design.........................................................................................................8
4.4 Liquefaction Potential..............................................................................................8
5.0 CONCLUSIONS AND RECOMMENDATIONS ..............................................................9
5.1 General.....................................................................................................................9
5.2 Overexcavations/Removals .....................................................................................9
5.3 Grading and Earthwork............................................................................................9
5.4 Preliminary Foundation Recommendations...........................................................11
5.5 Temporary Excavation...........................................................................................12
5.6 Review of Plans.....................................................................................................12
5.7 Geotechnical Observation and Testing..................................................................13
6.0 REFERENCES ..................................................................................................................14
7.0 LIMITATIONS..................................................................................................................15
TABLE OF CONTENTS (CONT'D)
ILLUSTRATIONS
Section Page
List of Figures
Figure 1. Site Location Map....................................................................................................2
Figure 2. Boring Location Map...............................................................................................5
List of Tables
Table 1. Summary of Fault Parameters..................................................................................7
APPENDICES
Appendix A - Field Exploration
Appendix B - Laboratory Test Results
Appendix C - Design Maps Summary Report
Appendix D - Standard Guidelines for Grading
Three on Cherry
October 26, 2018
Page: 1
1.0 INTRODUCTION
1.1 General
This report presents the results of a preliminary geotechnical investigation performed by Toro
International (TI) for a proposed new three-story multi-family building, located at 160 Cherry
Avenue, Carlsbad, California. A Site Location Map is presented in Figure 1 showing the
approximate location of the project site.
The purpose of the preliminary geotechnical investigation is to provide geotechnical design
parameters and recommendations for construction of the new multi-family building and its
associated site preparation and grading.
Our preliminary geotechnical investigation was conducted based on an architectural plans, issued for
Preliminary Review, entitled “Three on Cherry, 160 Cherry Avenue, Carlsbad, CA 92008,” prepared
by Di Donato Associates and dated December 12, 2018.
1.2 Proposed Development
Our understanding of the proposed construction is based on the above mentioned site plans. It is
our understanding that the size of the building footprint will be about 3,600 square feet. We
anticipate that cut and/or fill will be minor (less than 3 feet thick).
1.3 Site Description
The proposed site of the new multi-family building is currently a single family home on an about
7,000 square-feet lot. The property consists of a one-story house and its front and backyards that are
covered by grasses and sparse trees. The proposed site as well as the overall site is a relatively flat
area.
Page: 2
FIGURE 1
SITE LOCATION MAP
THREE ON CHERRY
Geotechnical Engineering
PROJECT: 03-125.7
TORO INTERNATIONAL
Three on Cherry
October 26, 2018
Page: 3
1.4 Scope of Work
The scope of work for this preliminary geotechnical investigation consisted of the following:
• Review of published reports and geologic maps pertinent to the site
• Field exploration, consisting of drilling and logging one boring to a maximum depth of 21.5
feet
• Laboratory testing of selected soil samples considered representative of the subsurface
conditions to evaluate the pertinent engineering and physical characteristics of the
representative soils
• Evaluation of the general site geology, including geologic hazards which could affect the
proposed development
• Evaluation of ground shaking potential resulting from seismic events occurring on
significant faults in the area
• Engineering analyses of the collected data to develop geotechnical recommendations for
seismic analyses, foundation of the proposed new multi-family building and its site
preparation
• Preparation of this report presenting our findings, conclusions, and recommendations.
Three on Cherry
October 26, 2018
Page: 4
2.0 FIELD EXPLORATION AND LABORATORY TESTING
2.1 Field Exploration
The subsurface conditions were explored by drilling one borehole. The depth of the borehole is
about 21.5 feet below the existing ground surface. The approximate location of the boring is shown
on the Boring Location Map in Figure 2. Details of the field exploration, including the logs of the
boring, are presented in Appendix A.
2.2 Laboratory Testing
Soil samples considered representative of the subsurface conditions were tested to obtain or derive
relevant physical and engineering soil properties. Laboratory testing included moisture content and
in-situ density, sieve analyses, direct shear and soluble sulfate content.
Moisture content and in-situ density test results are shown in the Borings Logs in Appendix A. The
remaining laboratory test results are presented in Appendix B. Descriptions of the test methods are
also included in Appendix B.
FIGURE 1
BORING LOCATION MAP
THREE ON CHERRY
Geotechnical Engineering
PROJECT NO. 03-125.7
TORO INTERNATIONAL LEGEND
B-1: Approximate Location of Boring No. B-1
B-
1
Page: 5
Three on Cherry
October 26, 2018
Page: 6
3.0 SITE CONDITIONS
3.1 Geology
The subject site is located approximately 56 feet above mean sea level. The site is located within the
Pleistocene Marine and Terrace Marine Deposits (Rogers, 1992). The marine and marine terrace
deposits are Quaternary in age and the thickness is probably over than one hundred feet. The marine
materials consist primarily of a mixture of silt and sand.
3.2 Groundwater
Groundwater was not encountered during our field exploration; however the maximum depth of the
borehole is about 21.5 feet below the existing ground surface.
3.3 General Subsurface Conditions
In general, the proposed multi-family building is underlain primarily by silty sand and silty sand to
sand materials. The silty sand and silty sand to sand materials are classified as SM and SM-SP,
respectively according to the Unified Soil Classification System (USCS).
The consistency of the coarse-grained soils is primarily medium dense. The equivalent Standard
Penetration Test (SPT) blow-counts of the subsurface materials ranges from 13 to 22 blows-per-foot
(bpf) with an average of about 19 bpf.
The moisture content of the coarse-grained soils ranges from 2.2 to 8.4 percent with an average of
about 5.5 percent.
Three on Cherry
October 26, 2018
Page: 7
4.0 SEISMICITY
4.1 General
Seismicity is a general term relating to the abrupt release of accumulated strain energy in the rock
materials of the earth’s crust in a given geographical area. The recurrence of accumulation and
subsequent release of strain have resulted in faults and systems of faults. The subject site is in
seismically active California.
4.2 Ground Motion
California Building Code (CBC). The most widely used technique for earthquake-resistant design
applied to low-rise structures is the California Building Code (CBC). The basic formulas used in the
CBC require determination of the site class, which represents the site soil properties at the site of
interest.
The nearest active fault is the Rose Canyon Fault, which is approximately 7.0 km away (Blake, T.
F., 1998). This fault and other nearest 7 faults, which could affect the site and the proposed
development, are listed in the following “Summary of Fault Parameters” as shown in Table 1.
TABLE 1. SUMMARY OF FAULT PARAMETERS
Fault Name
Approximate
Distance
(km)
Source Type
(A,B,C)
Maximum
Magnitude
(Mw)
Slip Rate
(mm/yr)
Fault Type
(SS,DS,BT)
Rose Canyon 7.0 B 6.9 1.50 SS
Newport-Inglewood (Offshore) 7.7 B 6.9 1.50 SS
Coronado Bank 33.0 B 7.4 3.00 SS
Elsinore-Temecula 39.6 B 6.8 5.00 SS
Elsinore-Julian 40.0 A 7.1 5.00 SS
Elsinore-Glen Ivy 54.7 B 6.8 5.00 SS
Palos Verdes 56.9 B 7.1 3.00 SS
Earthquake Valley 71.3 B 6.5 2.00 SS
Three on Cherry
October 26, 2018
Page: 8
4.3 Seismic Design
The 2016 CBC seismic zone for use in the seismic design formula is Site Class D. The Design Maps
Summary Report is included in Appendix C.
4.4 Liquefaction Potential
The subsurface soil consists predominantly of medium dense silty sand and silty sand to sand.
Groundwater was not encountered during our drilling; however the maximum depth of the borehole
is about 21.5 feet below the ground surface due to refusal encountered at that depth. Therefore,
based on the above-mentioned information, the subsurface soil materials at the proposed site are
considered not likely to liquefy during an earthquake.
Three on Cherry
October 26, 2018
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5.0 CONCLUSIONS AND RECOMMENDATIONS
5.1 General
Based on the results of our preliminary geotechnical investigation, it is our opinion from a
geotechnical viewpoint that the subject site is suitable for the proposed development and its
associated grading provided our geotechnical recommendations presented in this report are
implemented.
The remainder of this report presents our recommendations in detail. These recommendations are
based on empirical and analytical methods typical of the standard of practice in Southern California.
Other professionals in the design team may have different concerns depending on their own
discipline and experience. Therefore, our recommendations should be considered as minimum and
should be superseded by more restrictive recommendations of other members of the design team or
the governing agencies, if applicable.
5.2 Overexcavations/Removals
The upper 24 to 36 inches of subsurface soils may consist of roots and organic. Therefore, we
recommend that all deleterious materials including uncertified fill materials should be discarded off
site and the upper three feet of the subsurface materials be removed and replaced with compacted
fills. Upon completion of removal of the upper three feet of subsurface soil materials, the
geotechnical consultant should evaluate the bottom of the excavation and may make further
recommendations accordingly. Onsite soils may be reused. The extent of the removal should be
within the proposed additional building footprint and 3 feet beyond them, if possible. The removal
bottom and compacted fill should be prepared in accordance with the recommendations stated in
Section 5.3 below.
5.3 Grading and Earthwork
General. All earthwork and grading for site development should be accomplished in accordance
with the attached Standard Guidelines for Grading Projects (Appendix D), Appendix J of the CBC,
and requirements of the regulatory agency. All special site preparation recommendations presented
in the following paragraphs will supersede those in the attached Standard Guidelines for Grading
Projects.
Site Preparation. Vegetation, organic soil, roots and other unsuitable material should be removed
from the building areas. Prior to the placement of fill, the existing ground should be scarified to a
depth of 6 inches, and recompacted.
Three on Cherry
October 26, 2018
Page: 10
Prior to pouring concrete, the subgrade soil for the concrete slab area should be wetted to a slightly
higher than the optimum moisture to a depth of 6 inches from the surface.
Fill Compaction. All fill and backfill to be placed in association with site development should be
accomplished at slightly over optimum moisture conditions. The minimum relative compaction
recommended for fill is 90 percent relative compaction based on maximum dry density performed in
accordance with ASTM D-1557.
Fill should be compacted by mechanical means in uniform horizontal loose lifts not exceeding 8
inches in thickness.
Fill Material. The on-site soils can be used for compacted fill. However, during grading operations,
soil types other than those analyzed in the geotechnical reports may be encountered by the
contractor. The geotechnical consultant should be notified to evaluate the suitability of those soils
for use as fill and as finished grade soils.
Imported fill materials should be approved by the Geotechnical Engineer prior to importing. Soils
exhibiting any expansion potential should not be used as import materials.
Both imported and on-site soils to be used as fill materials should be free of debris, organic and
cobbles over 6 inches in maximum dimension.
Site Drainage. Foundation and slab performance depends greatly on how well runoff waters drain
from the site. This is true both during construction and over the entire life of the structure. The
ground surface around structures should be graded so that water flows rapidly away from the
structures without ponding.
In general, we recommend impermeable areas such as paved and concrete flatwork within a
minimum distance of 10 feet from a building (measured perpendicular to the face of the wall) should
be sloped away at a minimum gradient of 2%. Other areas such as lawn and vegetated areas should
have minimum descending gradients of at least 5% within 10 feet of the building (measured
perpendicular to the face of the wall)
Utility Trenches. Bedding materials should consist of sand having Sand Equivalent not less than 30,
which may then be jetted. Existing soils may be utilized for trench backfill provided they are free of
organic materials and rocks over 6 inches in dimension.
The backfill should be uniformly compacted to at least 90% relative compaction based on maximum
density performed in accordance with ASTM D-1557.
Three on Cherry
October 26, 2018
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5.4 Preliminary Foundation Recommendations
The following foundation recommendations were prepared without any information about the
structural configuration and maximum and average column loads of the new multi-family building.
Once the information is available, the following recommendations may be revised to reflect the
actual conditions of the proposed building.
In California, the foundation criteria given below have been generally observed to be practical in
mitigating the potential structural damage due to expansive soil pressures. The recommendations
below are based on our results of expansion index tests that indicate very low expansivity as defined
by the Section 1803 of CBC.
Additional expansion index tests need to be performed after completion of grading to verify that the
worst expansion index of the underlying soils is very low. If the test results indicate that the worst
condition of the underlying soils are not classified as very low, the recommendations below may be
adjusted accordingly.
Footing Design. The following minimum criteria should be adopted for the footing design in order
to maintain potential differential settlement less than ¼ inch:
a. Allowable Bearing Capacity: qall = 1,750 psf
b. Minimum Footing Width: 18 inches
c. Minimum Footing Depth: 24 inches
d. Minimum Reinforcement: 2 # 4 bars at both the top and bottom in
continuous footings
Notes:
i. Depth of footing is measured from the lowest adjacent grade.
ii. Allowable bearing capacity may be increased by one-third for short-term loadings.
iii. The above-mentioned footing dimension recommendations should not be considered
to preclude more restrictive criteria of regulating agencies or by a structural
engineer/architect.
iv. The design of the foundation system should be performed a structural engineer,
incorporating the geotechnical parameters described above.
Slab Design. The laboratory test results of the representative subgrade soils indicate that the
expansion index is 8, which falls within the very low expansion potential classification as defined by
the Section 1803 of current CBC. Therefore, no presaturation is required provided the compacted
fill will be placed in with moisture content one to two percent above the optimum.
Three on Cherry
October 26, 2018
Page: 12
The following recommendations should be incorporated for the slab-on-grade design:
a. The minimum thickness of slab-on-grade should be 5 inches.
b. The minimum steel reinforcement for slab-on-grade should be #3 located at mid-
height on 18-inch centers both ways
c. A modulus of subgrade reaction of 100 pounds per cubic inch (pci) may be utilized
for the slab design.
d. Modulus of Elasticity of Soil (Es): 1,000 pounds per square inch (psi)
e. Polyethylene Moisture Barrier (minimum 10-mil visqueen or equivalent) should be
placed-in below the slab; with approximately 2 inches of clean sand above the
moisture barrier and 2 inch of clean sand below the moisture barrier.
Cement Type. Based on the soluble sulfate test result, Type II cement and water-cement ratio of
0.45 or less may be used for concrete in contact with the on-site soils.
5.5 Temporary Excavation
Temporary excavation should be sloped back adequately to protect workers and protect against
sloughing. Based on our laboratory testing result and engineering analyses, the maximum gradient
for the temporary cut is 1:1 (horizontal:vertical) for onsite materials. Otherwise, temporary cut on
the onsite materials should be shored. Shoring should be designed and implemented by a specialty
contractor and should conform to the current Caltrans Trenching and Shoring Manual. Surcharge
loads due to the existing structure loading should be included in the design of the shoring, if any.
5.6 Review of Plans
The geotechnical consultant should review the final foundation and grading plans once they become
available in order to update and to provide detail and specific geotechnical recommendations for the
elements of the proposed development. The plans will also be compared to the site plan currently
used in the preparation of this report in order to evaluate the effect of any major changes with
respect to the geotechnical recommendations given in this report.
Three on Cherry
October 26, 2018
Page: 13
5.7 Geotechnical Observation and Testing
It is recommended that geotechnical observations and testing be performed by representatives of
Toro International at the following stages:
• Upon completion of remedial removals, prior to fill placement
• During removal bottom scarification
• During fill placement
• Upon completion of any footing excavation prior to pouring concrete
• During backfilling of any utility trenches
• When any unusual conditions are encountered
The geotechnical engineering firm providing geotechnical observation/testing shall assume the
responsibility of Geotechnical Engineer of Record.
Three on Cherry
October 26, 2018
Page: 14
6.0 REFERENCES
1. Blake, T. F., 1998,”UBCSEIS”, A Computer Program for the Estimation of Uniform
Building Code Coefficients Using 3-D Fault Sources”, January 1998
2. California Building Code (CBC), 2016
3 Rogers, Thomas H., 1992, “Geologic Map of California, Santa Ana Sheet,” 1992
Three on Cherry
October 26, 2018
Page: 15
7.0 LIMITATIONS
This report is intended for the use of Di Donato Associates for the proposed multi-family building,
Three on Cherry, at 160 Cherry Avenue, Carlsbad, California. This report is based on the project as
described and the information obtained from the borings and other field investigations at the
approximate locations indicated on the plans. The findings are based on the results of the field,
laboratory, and office investigations combined with an interpolation and extrapolation of conditions
between and beyond the boring locations. The results reflect an interpretation of the direct evidence
obtained. The recommendations presented in this report are based on the assumption that an
appropriate level of field review (observations and tests) will be provided during construction. Toro
International should be notified of any pertinent changes in the project plans or if subsurface
conditions are found to vary from those described herein. Such changes or variations may require a
re-evaluation of the recommendations contained in this report.
The soil samples collected during this investigation are believed representative of the areas sampled.
However, soil conditions can vary significantly between and away from the locations sampled. As
in most projects, conditions revealed by additional subsurface investigations may be at variance with
preliminary findings. If this occurs, the geotechnical engineer must evaluate the changed condition,
and adjust the conclusions and recommendations provided herein, as necessary.
The data, opinions, and recommendations of this report are applicable to the specific design
element(s) and locations(s) which is (are) the subject of this report. They have no applicability to
any other design elements or to any other locations and any and all subsequent users accept any and
all liability resulting from any use or reuse of the data, opinions, and recommendations without the
prior written consent of Toro International.
Toro International has no responsibility for construction means, methods, techniques, sequences, or
procedures, or for safety precautions or programs in connection with the construction, for the acts or
omissions of the contractor, or any other person performing any of the construction, or for the failure
of any of them to carry out the construction in accordance with the Final Construction Drawings and
Specifications.
Services performed by Toro International have been conducted in a manner consistent with that level
of care and skill ordinarily exercised by members of the profession currently practicing in the same
locality under similar conditions. No other representation, express or implied, and no warranty or
guarantee is included or intended.
APPENDIX A - Field Exploration
Subsurface conditions were explored on October 11, 2018 by drilling one boring to a maximum
depth of approximately 21.5 feet below the existing grade below the existing grade. The drilled
borehole was advanced by an 8-inch-diameter-hollow-flight-auger drilling rig mounted to a truck.
The drilled borehole was located in the field by tape measurements from known landmarks. Its
location as shown is therefore within the accuracy of such measurements.
The field explorations were performed under supervision of our engineer who prepared detailed logs
of the borings, classified the soil encountered, and obtained soil samples for laboratory testing.
Relatively undisturbed soil samples were obtained by means of driving a 2.5-inch diameter sampler
having a hammer weight and drop of 140 pounds and 30 inches, respectively. Standard Penetration
Tests (SPT) tests were also carried out at alternating intervals with the drive sampler. The
sampling/SPT interval is about 5 feet. Small bulk samples obtained from the SPT tests were
collected for further evaluation in the laboratory.
The Boring Logs show the type of sampler, weight and drop of the hammer, number of hammer
blows and soil stratigraphy. The soils were classified based on visual observations during the field
investigation and results of the laboratory testing. Soil classifications were conducted in accordance
with the Unified Soil Classification System.
TORO INTERNATIONAL
GEOTECHNICAL ENGINEERING
Project Name Three on Cherry Site Address 160 Cherry Avenue, Carlsbad
Project Number 03-125.7 Date 10/11/2018
Equipment Hollow Stem Flight Auger Drive Weight 140 lbs
Average Drop 30 inches Elevation (ft)56 (Assumed)
Hole Diameter 8 inches Engineer/Geologist HW
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GEOTECHNICAL DESCRIPTION
PLEISTOCENE MARINE AND MARINE TERRACE DEPOSITS
B-1
R-1 20 111 2.2 SM @ 2': Brown fine silty sand, dry to damp, medium dense
551
R-2 24 111.2 6.8 SM-SP @ 5': Dark brown fine silty sand to sand, damp, medium dense
10 46
S-1 22 102.8 8.4 SM-SP @ 10': Reddish brown fine to medium silty sand to sand, damp to moist,
medium dense
15 41
S-2 20 - 5.4 SM-SP @ 15': Grayish brown fine silty sand to sand, damp, medium dense
20 36
S-3 22 - 4.7 SM-SP @ 20': Reddish brown fine to medium silty sand to sand, damp, medium dense
Total Depth: 21.5 feet
No Groudwater was Encountered
25 31
30
BORING NO. B-1
Sheet 1 of 1
APPENDIX B - LABORATORY TESTING PROCEDURES AND RESULTS
Moisture Content and Dry Density
Moisture content was determined for small bulk and relatively undisturbed ring samples. Dry
Density was determined for relatively undisturbed ring samples only. The test procedure is in
accordance with ASTM 2216-90. The results of moisture content and dry density are presented in
the Boring Logs.
Expansion Index
Expansion Index tests were performed using California Building Code Test Method 29-2. The
results of the tests are shown in Table B-1.
Soluble Sulfate Content
Soluble Sulfate Content test was run in accordance with the California Test Methods (CTM) 417.
The test result is shown in Table B-2
Sieve Analyses
Sieve analyses were performed on granular materials in accordance with ASTM D 422. Graphs
showing relationship of the various sizes of soil particles versus percentage passing are shown in
Figure B-1.
TABLE B-1. EXPANSION INDEX TEST RESULTS
Boring Number
Depth (feet)
Soil Description
Expansion
Index
Expansion
Classification
B-1
0-5
Brown Silty Sand
8
Very Low
TABLE B-2. SOLUBLE SULFATE CONTENT
Boring Number
Depth (feet)
Soil Description
Soluble Sulfate
Content (ppm)
B-1
0-5
Brown Silty Sand
126
Sample Depth Percent Passing
(ft) No. 200 Sieve
B-1 S-1 10 12.0 SM-SP
Project Name: Three on Cherry
Project No.: 03-125.7 Figure: B-1
TORO INTERNATIONALGRAIN SIZE DISTRIBUTION CURVE
ASTM D422
Boring No. Sample No. Soil Type
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110100
Particle Diameter in Millimeters
Pe
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P
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Sample Depth Friction Angle Cohesion
(ft) (degrees) (psf)
B-1 5 31 0 Peak
29 0 Relaxed
Project Name: Three on Cherry
Project No.: 03-125.7 Figure: B-4
ASTM D3080
ConditionBoring No.
TORO INTERNATIONALDIRECT SHEAR TEST
0
1000
2000
3000
4000
5000
0 1000 2000 3000 4000 5000
NORMAL STRESS (psf)
SH
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(
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)
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Relaxed
APPENDIX C
DESIGN MAPS SUMMARY
APPENDIX D
STANDARD GUIDELINES
for
GRADING PROJECTS
,
2 •
STANDARD GUIDELI:-lES ,OR GRADI:lG r'?.OJECTS
GENERAL
1 • 1 ~epresencacives of the Geocechnical Consultant should
be present on-site during grading operations in order
to make observations and oerform tests so that
professional opinions can.be developed. The opinion
will address whether grading has proceeded in
accordance with the Geotechnical Consultant's
recommendations and applicable project specifications;
if the site soil and geologic conditions are as . . .
. ancic-ipa:ced · · i:n 'the ·"prel i1liiniiry ·'i.hves·c1.g·a:t"{ori";·• 'anl 'if .. , .
additional recommendations are warranted by any
unexpected s ice conditions. Services do not :.nclude
supervision or direction of :~e actual work of :he
concraccor, his employees or agents.
1.2 The guidelines contained herein and the standard
details attached hereto represent this firm's standard
recommendations for grading and ocher associated
operations on construction projects. These guidelines
should be considered a portion of the report to which
they are appended.
1.3 All places attached hereto shall be considered as pare
of these guidelines.
1 .4 The Contractor should not vary from ·chese guidelines
without prior recommendation by the Geocechnical
Consultant and the approval of the Client or his
auchori=ed representative.
1 • 5 7hese Standard Gradin2 Guidelines and Standard Details
ma.y .b.e modi-fied aoo/or superseded bv · i:'eto"milleft'da·tions .
contained in the text of the oreliminarv geocechnical
report and/or subsequent reports. ·
1.6 If disputes arise out of the interpretation of these
grading guidelines or standard details. the Geocech-
nical Consultant shouid deter::iine the appropriate
incerpreca c ion.
DE.FINITIONS OF TERMS
2.1 ALLUVIUM --Unconsolidated detrital deposits resulting
from flow of water, including sediments deposited in
river beds. canyons. ::lood plains. lakes. :ans at the
foot of slopes and estuaries.
Standard Guidelines
for Grading Projects Page 2
2.2
2.J
2.4
.. ... . •'•.
AS-GRADED !AS-BUILT) --,he surface and subsurface
conditions at completion of grading.
BACKCUT --A temporary construction slope at the rear
of earth retaining structures such as buttresses,
shear keys, stabilization fills or retaining walls.
BACKDRAIN --Generally a pipe and ~ravel or similar
drainage system placed behind earth retaining
structures such buttresses, stabilization fills, and
retaining. walls. , ...... , .... · ..... · .•. , .... .-~ ,· ,_. .. : •• •• • •·-<(. • • .,· ........... ~ •..... : •• • .... ••• '• ••
2.5 BEDROCK --A more or less solid. relatively undis-
turbed rock in place either at the surface or beneath
superf~cial deposits of soil.
2.6 BENCH --A relatively level step and near vertical
rise excavated into sloping ground on which fill is to
be placed.
2.7 BORROW (Import) --Any fill material hauled to the
project site from off-site areas.
2.8 BUTTRESS FILL --A fill mass. the configuration of
which is designed by engineering calculations to
retain slope conditions containing adverse geologic
features. A buttress is generally specified by
minimum key width and depth and by maximum backcut
angle. A buttress normally contains a backdrainage
system.
2.9 CIVIL ENGINEER --The Reg{stered Civil Engineer or
cons':11ting firm. respo:7s,~~l~ :_o~--~rE!pa_,r_ati()n_ of -~he · •-.. ,., · ~ra-d:tng•·pla:ns .··-surveying an·d ver1fy1ng as-graded ·
topographic conditions.
2.10 COLLUVIUM --Generally loose deposits usually found
near the base of slopes and brought there chiefly by
gravity through slope continuous downhill cree? (also
see Slope \./ash).
2.11 COMPACTION --Is the densification of a fill by
mechanical means.
2.12 CONTRACTOR --A person or company under contract or
otherwise retained bv the Client :o perform
demolacion, grading ~nd ocher site improvements.
. •: .-... · ... , .. :,
candard Guidelines
or Grading Projects
?age 3
~.13 DEBRIS --All ?roduccs of ciearine, ~rubbing,
demoiition, contaminated soil material unsuicable for
reuse as compacted fill and/or anv other ~acerial so
designated by the Geocechnical Consulcanc.
2.14 ENGINEERING GEOLOGIST --A Geologist holding a valid
certificate of registration in the specialty oc
Engineering Geology.
2.15 ENGINEERED FILL --A fill of which the Geocechnical
Consultant or his represenca_t,.i,".'~, .. c!:U.t:.tl'(g._,g,ri;l~t11.1t,.-_has.
"'' ··niade··suff1i:'i'ent·te~fs c·o··enable him ·co conclude that
the fill has been placed in substantial compliance
with the recommendations of the Geocechnical
Consultant and the governing aeencv reouiremencs.
~.16 EROSION --The wearing awav of the ground surface as a
result of the movement of wind, water, and/or ice.
2.17 EXCAVATION
materials.
The mechanical removal of earth
2.18 EXISTING GRADE --The ground surface configuration
prior co grading.
2.19 FILL --Any deposits of soil, rock, soil-rock blends
or other similar materials placed by man.
2.20 FINISH GRADE --The ground surface configuration at
which time the surface elevations conform co the
approved plan.
2.21 GEOFABRIC --Anv engineering textile utilized in
... , .. ,. ··· --~eotechni.cal· a-p~iica:ciohs ··1ficliidfn'g' 'sub·g·ra:ire·· ... , .. , .
· stabilization and :iltering.
2.22 GEOLOGIST --A representative of the Geocechnical
Consultant educated and trained in the field of
geology.
.......
2.23 GEOTECHNICAL CONSULTANT --The Geotechnical Engineer-
ing and Engineering Geology consulting firm retained
co provide technical services for the pro.i ect. For
the purpose of these guidelines, observations by the
Geotechnical Consultant include observations by the
Geotechnical Engineer, Engineering Geologist and those
performed by persons employed by and responsible to
the Geotechnical Consultants.
·•: . . . . . ·.• . .
Standard Guidelines
for Grading Projects Page 4
2.24 GEOTECHNICAL ENGINEER --A licensed Civil Engineer who
applies scientific methods, engineering principles and
professional experience co the acquisition, :.nter-
pretation and use of knowledge of materials of the
earth's crust for che evaluation of engineering
problems. Geotechnical Engineering encompasses many
of the engineering asoects of soil rnechanics, rock
mechanics, geology, geophysics, hydrology and related
sciences .
. 2. 25 ... , GRAP.IN~ .. --: . .A\1.Y _9_P,.e:r2;_t iqn .. cor,s i st.ini; .. of exc_a.lla t ion., ..
• ·· ftll[ng ~r··cojbinations thereof and associated
operations.
2.26 LANDSLIDE DEBRIS --(-!aterial, generally porous and of
low density, produced :rom instability or natural of
man-made slopes.
2.27 MAXIMUM DENSITY --Standard laboratory test for
maximum dry unit weight. Unless otherwise specified,
the maximum dry unit weight shall be determined in
accordance with ASTM Method of Test D1557.
2.28 OPTIMUM MOISTURE --Test moisture content at the
maximum density.
2.29 RELATIVE COMPACTION --The degree of compaction
(expressed as a percentage) of dry unit weight of a
material as compared to the maximum dry unit weight of
the material.
2.30 ROUGH GRADE --The ~round surface configuration at
which time the surface elevations. aoproximateLv_. •· '.·· ·-·· .. · conform· ta th~··app'i:'ovea .plan;·· .... ·•• .... ·· -: , ... -..... -
2. 31 SITE --The oarticular parcel or land where grading is
being performed.
2.32 SHEAR KEY --Similar to buttress, however, it is
generally constructed bv excavating a slot within a
natural slope in order co stabilize the upper ?Ortion
of the slope without grading encroaching into the
lower 7ortion of the slope.
2.33 SLOPE --Is an inclined ground surface the steepness
of which is generally soecified as a ratio of
hori::ontal:vertical (e.g., 2: 1).
2.34 SLOPE wASH --Soil and/or rock material chat has been
transported down a slope by mass wasting assisted by
runoff water not confined by channels (also see Colluvium).
canciarw Guideii~es
or Gracing ?rejects ?age 5
2.35
2.36
2.37
·: .. · -.-: :-
~OIL --Nacurallv occurring deoosi:s of sand, 5ilt,
clay, etc., or combinations chereof.
SOIL ENGINEER --Licensed Civil Engineer exoerienced
in soil mechanics (also see Geocechnical Engineer).
STABILIZATION FILL --A fill mass, the configuration
of which is typically related co slope height and is
specified by the standards of practice for enhancing
the stability of locally adverse conditions. A
stabilization_ fill ~s. l)Ormally.s.peci_f~_ed . .t,y m,ini.mum ·· •. ,
~k'ey'w{citfi ·and°·depcn ·and by max.imum· backcuc angle. A
stabilization fill may or may not have a backdrainage
system specified.
2.38 3UBDRAIN --Generally a pipe and gravel or similar
drainage system placed beneath a fill in the alig~menc
of canyons or former drainage channels.
2.39 SLOUGH --Loose, noncompacced fill material generated
during grading operations.
2.40 TAILINGS --Nonengineered fill which accumulates on or
adjacent co equipment haul-roads.
2.41 TERRACE --Relatively level seep constructed in the
face of graded slope surface for drainage control and
maintenance purposes.
2.42 TOPSOIL --The presumably fertile.upper zone of soil
which is usuall~ darker in color and loose.
2.43 ~INDROW --A sering of large rock buried_wich~n.
., ... -·eng·i:neered· fi•ll •i·n •·a:ctcrdanc·e·';;Tcn'·gui.del'iries ·sec·
forth by the Geotechnical Consultant.
3. SITE PREPARATION
. ... ,
3.1 Clearing and grubbing should consist of the removal of
vegetation such as brush, grass, woods, stumps, trees,
roots co trees and otherwise deleterious natural
materials from the areas co be graded. Clearing and
~rubbing should extend co the outside of all proposed
excavation and fill areas.
3.2 Demolition should include removal of buildings, struc-
tures, foundations, reservoirs, utilities ( including
underground pipelines, septic tanks, leach fields,
seepage pits, cisterns, mining shafts, tunnels, etc.)
and other man-made surface and subsurface improvements
Standard Guidelines
Ear Grading Projects Page 6
from the areas co be graded. ,emolicion of utilities
should include proper canping and/or re-routing pipe-
lines at the project perimeter and cutoff and capping
of wells in accordance with che requirements of the
governing authorities and the recommendations of the
Geocechnical Consultant at the time of demolition.
3.3 Debris generated during clearing, grubbing and/or
demolition operations should be wasted from areas co
be graded and disposed off-site. Clearing, grubbing
.. and __ ~emol_ici9r1 _o_pe;-_~c;o_ns_ ~h.o,ulq,~~ P.e_rf9.i:i11ed_ •. uJ1der.. .,
· · ·tne··obs·erv'"aciori· of the Geocechnical Consulcanc.
SITE PROTECTION
4.1 The Contractor should be responsible for the stability
of all temporary excavations. Recommendations by the
Geotechnical Consultant pertaining co temporary
excavations (e.g., backcucs) are made in consideration
of stability of the completed project and, therefore,
should not be considered co preclude the responsibil-
ities of the Contractor. Recommendations by the
Geotechnical Consultant should not be considered to
preclude more restrictive requirements by the
regulating agencies.
4.2 Precautions should be taken during the performance of
site clearing, excavations and grading co protect the
work site from flooding, ponding or inundation by poor
or improper surface drainage. T~mporary provisions
should be made during the rainv ~eason co adequately
· direct surface draina·ge away :'~om ·and off the work
site.
. .,, .. .,. .... . .. ·: ........ :•· .... .
4 • 3 During ?eriods of rainfall, the Geocechnical
Consultant should be kept informed by the Contractor
as co the nature of remedial or preventative work
being performed (e.g., pumping, placement of sandbags
or plastic sheeting, ocher labor, dozing, ecc.).
4.4 . Following periods of rainfall, che Contractor should
contact the Geocechnical Consultant and arrange a
review of ·the site in order co visually astess rain
related damage. The Geocechnical Cons~lcanc may also
recommend excavations and testing in order co aid in
his assessments.
4.5 Rain related damage should be considered co include,
but may not be limited to, erosion, silting,
saturation, swelling, structural distress and ocher
adverse conditions identified by the Geocechnical
Standard Guidelines
for Grading Projects '?age 7
Consultant. Soil adverselv aifecced should be
classified as Unsuitable Materials and should be
subject co overexcavacion anci replacement with
compacted fill or ocher remedial grading as
recommended by the Geocechnical Consultant.
5. EXCAVATIONS
5.1 UNSUITABLE MATERIALS
5 • 1 • 1
.. ••· ... :., .. ,
5. 1 • 2
Mace rials, which ar.e .. u_ns,'4,i. t;:abl.e s.hoµld ._.b_e _ ...
.. excav·afed 'i.111a·er. obs:ervac1011 and recommendations
of the Geotechnical Consultant. Unsuitable
materials include, but may not be limited co,
dry, loose, soft. wet. organic compressible
natural soils and fractured, weathered, ~oft
bedrock and nonengineered or otherwise
deleterious fill materials.
Material identified by the Geotechnical
Consultant as unsatisfactory due to its
moisture conditions should be overexcavaced,
watered or dried, as needed, and thoroughly
blended to a uniform near optimum moisture
condition (as per guidelines reference 7.2.1)
prior co placement as compacted fill.
5. 2 CUT SLOPES
s.2.1
5. 2 _ 2
5.2.J
Unless otherwise recommended by the G~otech-
nical Consultant and approved by tqc_reg~lating
agenci·es, ?erma·nenc cue ·slopes should no c :ie
steeper :San 2: 1 (horizoncal:vercical).
. . . ,.,,, •· ; r: .· ' .. • •. ·• . . -·. . •· • ·• ~ . ,... ' ., • • . ·., .• _.,_ •·
If excavations :or cut slopes expose loose,
cohesionless, significantly fractured or
otherwise unsuitable material, overexcavation
and replacement of the unsuitable materials
with a compacted stabilization fill should be
accomplished as recommended by the Geocechnical
Consultant. Unless otherwise specified by the
Geotechnical Consultant, stabilization fill
construction· should c·onforn co the requirements
of the Standard Details.
The Geocechnical Consultant should review cut
slopes during excavation. The Geotechnical
Consultant should be notified by the contractor
prior to beginning slope excavations.
Stanoarc Guidelines
for Grading Projects Page 8
5.2.~ !f, juring the course of grading, 3dverse or
potenciaily adverse geocechnical conditions are
encountered which were not anticipated in the
preliminary report, :he Geocechnical Consultant
should explore, analyze and make recommen-
dations to creac these problems.
6. COMPACTED FILL
i ·. -.. • ·.
All fill materials should be compacted co ac lease 90
percent of max~mum qen~_ity_ ,\A\>'):'lf,D.1 S;i}) .unless .. o?he.rwise ... · ...
·tecorhmerided by" ·che··ceotechnical Consultant.
6. 1 PLACEMENT
... ,.
6. 1 .1 Prior to placement of compacted fill, che
Contractor should request a review by the
Geocechnical Consultant of the exposed ground
surface. Unless otherwise recommended, the
exposed ground surface should then be scarified
(6-inches minimum), watered or dried as needed,
thoroughly blended to achieve near optimum
moisture conditions, then thoroughly compacted
to a minimum of 90 percent of the maximum
density,
6.1 .2 Compacted fill should be placed in thin
horizontal lifts. Each lift should be watered
or dried as needed, blended co achieve near
optimum moisture conditions then compacted by
mechanical methods to a minimum _of 90 percent
of laboratory maximum dry densitv. C:ach lift
should be treated in a like manner until t~~
• • ' • . .. • • J· . • ••• • • •• • • -... _ ., • • .• .. • •• • •• •• ·-ct·esiI'ed f1r!1sh·ect grades are achlevea .
6.1 .J When placing fill in horizontal lifts adjacent
to areas sloping steeper than 5:1 (horizontal:
vertical), horizontal keys and vertical benches
should be excavated into the adjacent slope
area. Keying and benching should be sufficient
to provide ac least 6-fooc wide benches and a
minimum of ~-feet of vertical bench height
within the firm natural ground, firm bedrock or
engineered compacted fill. No compacted fill
should be placed in an area subsequent co
keying and benching until the area has been
reviewed by the Geocechnical Consultant.
Material generated by the benching operation
should be moved sufficiently away from the
bench area co allow for the recommended review
of the horizontal bench prior to placement
.. :•
-. ·-··
··•-: , ..
canaara Guidelines
or Grading Projects
?age 9
6. 1 • 4
fill. Typical ~eying and benching details have
been included within :~e accompanying Standard
Details.
Within a single fill area where graa1ng
procedures dictate two or more separate fills,
temporary slopes (false slopes) may be created.
When placing fill adjacent to a false slope,
benching should be conducted in the same manner
as above described. At least a 3-fooc vertical
bench should be established within the firm
core .adj.acenc ..appr.o.ved -.compac-ted, fi·ll"p-rior·'·co··· · ·.· ... · •
placement of additional fill. Benching should
proceed in at least 3-foot vertical increments
until the desired finished grades are achieved.
6.1.5 Fill should be tested for compliance with the
recommended relative compaction and moisture
conditions. Field density testing should
conform co accepted test methods. Density
testing frequency should be adequate for the
geotechnical consultant to provide professional
opinions regardings fill compaction and
adherence to recommendations. Fill found not
co be in conformance with the grading
recommendation should be removed or otherwise
handled as recommended by the Geotechnical
Consultant.
6.1 .6 The Contractor should assist the Geotechnical
Consultant and/or his representative bv digging
test pits for removal decer-minations ~nd/or for
testing compacted fill.
As ·re-c~mm~~-ded i',; ···the Geo technical ··c~~-sui~;~t,
the Contractor may need co remove grading
equipment from an area being tested if
personnel safety is considered to be a problem.
6.2 MOISTURE
6.2.1 For field testing purposes "near optimum"
moisture will vary with mat~rial type and other
factors including compaction procedure. "Near
optimum" may be specifically recommended in
Preliminary Investigation Reports and/or may be
evaluated during grading.
6.2.2 Prior to placement of additional compacted fill
following an overnight or ocher grading delay,
the exposed surface or previously compacted
. ... ;..: .
· .. · ....
Stanaard Guidelines
for Grading Proieccs Page 10
6.2.3
fill should be processed bv scarification,
watered or dried as needed, choroughlv blended
co near-optimum moisture conditions, ~hen
recompacted to a minimum of 90 percent of
laboratory maximum dry density. \Jhere wee,
dry, or other unsuitable materials exist to
depths of greater than one foot, che unsuitable
materials should be overexcavated.
Following a period of flooding, rainfall or
overwatering by ocher means, no additional fill
.should-.he, placed. unc-i-1 · damage ·ass!!ssn\en·t·s· have .
been made and remedial grading performed as
described under Section 5.6 herein.
A.3 :'ILL :'ATERIAL
6.3.1 Excavated on-site materials which are
considered suitable to the Geocechnical
Consultant mav be utilized as compacted fill,
provided trash, vegetation and other
deleterious materials are removed prior to
placement.
6.3.2 Where import fill materials are required for
use on-site, the Geo technical Consultant should
be notified in advance of importing, in order
to sample and test materials from proposed
borrow sites. No import fill materials should
be delivered for use on-site without prior
sampling and cescing notification bv
Geotechnical Consultant ..
6.3.3 .... , ........ •'•'
'-v'here oversized rock-. or .. s.i111iJ,ar-Lr--r-eduei-ble -
mai:e-r"ia"i Ls generated during grading' it is
recommended, where practical, co waste such
material off-site or on-site in areas
designated as "nonstructural rock disposal
areas''. Rock placed in disposal areas should
be placed with sufficient fines to fill
voids. The rock should be compacted in lifts
to an unyielding condition. The disposal area
should be cove,ed with at least three feet of•
compacted fill which is free of oversized
material. The upper three feet should be
placed in accordance with the guidelines for
compacted fill herein.
6.3.4 Rocks 12 inches in maximum dimension and
smaller may be utilized within the compacted
fill, provided they are placed in such a manner
.. ·•··'
...•
3tanaard Guidelines
for Grading Projects Page 11
6. 3. 5
, ... · ....... ,
that nescing of che rock is avoided. Fill
should be placed and thoroughly compacted over
and around all rock. The amount of rock should
not exceed 40 percent by ary weight retained on
the 3/4-inch sieve size. The i2-inch and 40
percent recommendations herein may vary as
field conditions dictate.
Where rocks or similar irreducible materials of
greater than 12 inches but less than four feet
of maximum dimension are generated during
..... grad ii.~ •.. or. .-otherw.i.se-.desir.ed. ,to· he ·p 1-aced·. · •·· .·
within an engineered fill, special handling in
accordance with the accompanying Standard
Details is recommended. Rocks greater than
four feet should be broken down or disposed
off-site. Rocks up to four feet maximum
dimension should be placed below the upper 10
feet of any fill and should not be closer than
20-feet co any slope face. These recommen-
dations could vary as locations of improvements
dictate. Where practical, oversized material
should not be placed below areas where
structures or deep utilities are proposed.
Oversized material should be placed in windrows
on a clean, over.excavated or unyielding
compacted fill or firm natural ground surface.
Select native or imported granular soil (S.E.
30 or higher) should be placed and thoroughly
flooded over and around all windrowed rock,
such that voids are filled. ~indrows of
oversized material should be staggered so ch•c
successive strata of oversized material are not
in the same ver.cical p.l_ane.. ...... : .. •. . . . ..... , ... .-.. ~ ....... ,, .. ".; ,, ......... .
6.3.5 le may be possible co dispose of individual
larger rock as field conditions dictate and as
recommended by the Geotechnical Consultant ac
the time of placement.
6.3. 7 The construction of a "rock fill" consisting
primarily of rock fragments up co two feet in
maximum dimension with little soil material may
be feas'ible. Such material is typically
generated on sites where extensive blasting is
required. Recommendations for conscruccion of
rock fills should be provided by the
Geocechnical Consultant on a site-specific
basis.
,candard Guidelines
:or Gracing Projects Page I 2
·•· ..
6 • 3 • 8
.· ....... .
6.3.9
Juring graa1ng ooerations, ?lacing and mixing
che materials fr~m the cue and/or borrow areas
may result in soil mixtures which possess
unique physical ?ropercies. Testing may be
required of samples obtained directlv from the
fill areas in order co determine conformance
with the specifications. Processing of these
additional samples may take two or more working
days. The Contractor may elect co move the
operation co other areas within the project, or
may continue placing compacted fill pending
laboratorv and field test results. Should he
'"elect.the·.se.cond-alcernatiV!!, 'fill pla·ced ts'··
done so ac the Contractor's risk.
Any fill placed in areas not previously
reviewed and evaluated bv the Geocechnical
Consultant may require removal and recom-
paction. Determination of overexcavations
should be made upon review of field conditions
by the Geotechnical Consultant.
6.4 FILL SLOPES
6.4.1 Permanent fill slopes should not be constructed
steeper than 2: 1 (horizontal to vertical),
unless otherwise recommended by the Geotech-
nical Consultant and approved by the regulating
agencies.
6. 4. 2
.....
Fill slopes should be compacted in accordance
with these grading guidelines and specific
report recommendations. Two methods or slope
compaction are cvpically utilized in mass
g_ ~!ld i !1!'., . lat er .a 1. .i;,:ve.r ·:!:mi 1-di ng _.and· cus: t: i ng -b-a-clc ,
ancf mechanical compaction co g·rade (i.e.
sheepsfooc roller backrolling). Constraints
such as height of slope, fill soil type, access,
property lines, and available equipment will
influence the method of slope construction and
compaction. The geotechnical consultant should
be notified by the contractor what method will.
be employed prior to slope construction.
Slopes utilizing over-building and cutting back
should be constructed utilizing horizontal fill
lifts (reference Section 6) with compaction
equipment working as close to the edge as prac-
tical. The amount of lateral over-building will
varv as field conditions dictiate. Compaction
testing of slope faces will be required and
Stanaara Guidelines
for Grading Projects ?age 1 3
reconstruction of the slope ~ay result .•
testing does r.ot ~eet our recommendations.
Mechanical compaction of the slope co grade
during constru~tion should utilize cwo types of
compactive effort. First, horizontal fill lifts
should be compacted during fill placement. This
equipment should provide compactive effort to
the outer edge of the fill slope. Sloughing of
fill soils should not be permitted to drift down
the slope. Secondly, at intervals not exceeding
-four.-feet. i.n vertical-slope he-ighc ·or ch·e· ·. ·· • ..
capability of available equipment, whichever is
less, fill slopes should be backrolled with a
sheepsfoot-type roller. Moisture conditions of
the slope fill soils should be maintained
throughout the compaction process. Generally
upon slope completion, the entire slope should
be compacted utilizing typical methods, (i.e.
sheepsfoot rolling, bulldozer tracking, or
rolling with rubber-tired heavy equipment).
Slope construction grade staking should be
removed as soon as possible in the slope
compaction process. Final slope compaction
should be performed without grade sakes on the
slope face.
In order to monitor slope construction
procedures, moisture and density tests will be
taken at regular intervals. Failure to achieve
the desired results will likelv result in a
recommendation bv the Geotechnical Consultant
to overexcavate ~he slope surfaces ·followed hy
.r:.eq,i:is.tr1;1_ct_ion. o.f ,th~ .slopei. ut:il,i:z.ing -over~--......... ·· ·
filling and cutting back procedures or further
compactive effort with the conventional
backrolling approach. Other recommendations
may also be provided which would be
commensurate with field conditions.
6.4.3 Where placement of fill above a natural slope
or above a cut slope is proposed, the fill
slope configuration as presented in the
accompanying Standard Details should be
adopted.
6.4.4 For pad areas above fill slopes, ?Ositive
drainage should be established away from the
top-of-slope, as designed by the project civil
engineer.
... '·.
Standard Guidelines
for Grading Projects ?age 14
.... ·
A.5 OFF-SITE FILL
6.5.1 Off-site fill should be created in the same
manner as recommended in the specifications for
site preparation, excavation, drains,
compaction, etc.
6.5.2 Off-site canyon fill should be placed in
preparation for future additional fill, as
shown in the accompanying Standard Details •
. 6 •. 5. 3 Off-si.te. fill ·subdrai-ns· cemporar·ily cenrrinated···
(up canyon) should be surveyed for future
relocation and connection.
~.6 TRENCH BACKFILL
6.6.1 Ucilicv trench backfill should, unless other-
wise recommended, be compacted by mechanical
means. Unless otherwise recommended, the
degree of compaction should be a minimum of 90
percent of maximum density (ASTM D1557).
6.6.2 Backfill of exterior and interior trenches
extending below a 1:1 projection from the outer
edge of ·foundations should be mechanically
compacted co a minimum of 90 percent of the
laboratory maximum density.
6.6.3 ~ithin slab areas, but outside the influence of
foundations, trenches uo co one foot wide and
-two feet deeo mav be ba~kfilled with sand• (S.E .. > 30), and consolidated by jetting, .:loading or
.. _by .mt;!\:h.apical means ... ·it. or,-_s..ic.e .mac-eri..als ,are .. · ·
·· tltilized, ·c~ey should be wheel-rolled, camped
or otherwise compacted co a firm condition.
For minor interior trenches, densicv testing
may be deleted or spot testing may be elected
if deemed necessary, based on review of
backfill operations during construction.
6.6.4 If utility contractors indicate chat it is
undesirable co use compaction equipment in
close proximity co a buried conduit, the
Contractor mav elect che utilization of light
weight mechanical compaction equipment and/or
shading of the conduit with clean, granular
material, (S.E. > 30) which should be
thoroughly moistened in the trench, prior co
3canaard Guideiines
for Grading Projects
Page 15
:niciacing mechanical oomoaccion orocedures.
Other methods of ucilicv ~rench·comoaccion mav
also be appropriate, upon review of° the
Geocechnical Consulcanc ac :he cirne of
conscruccion.
n.6.5 In cases where clean granuiar materials are
proposed for ~se in lieu of native materials or
where flooding or jetting is proposed, che
procedures should be considered subject co
review by che Geocechnical Consulcanc •
6. 6. 6
·-. ~. .. . •
Clean granular backfill and/or bedding are nee
recommended in slope areas unless provisions
are made for a drainage svscem co micigace the
pocencial build-up of s2e~age ~orces Rnd
piping.
7. DRAINAGE
8 •
7.1 Canyon subdrain systems recommended by che
Geotechnical Consultant should be installed in
accordance with the Standard Details.
7.2 Typical subdrains for compacted fill buttresses, slope
stabilizations.or sidehill masses, should be installed
in accordance with che specifications of che
accompanying Standard Details.
7.3 Roof, pad and slope drainage should be directed awav
from slopes and areas of scruccures co disoosal areas
via suitable devices designed bv che proiecc civil
engineer ,:i.e., guccers, ::ownspoucs, concrete swales,
area drains, eai;-ch swales, ~tc .•. i.,_ .. , .. · ... , ••. . . . . . . . ... , .
7.4 Drainage oaccerns established cc :he cime ot tine
grading should be maintained chroughouc che life of
the project. Property owners should be made aware
chat altering drainage paccerns can be decrimencal co
slope scabilicy and foundation performance.
SLOPE ~INTENANCE
8.1 LANDSCAPE PLANTS
In order co decrease erosion surficial slope stability
problems, slope planting should be accomplished ac che
completion of grading. Slope planting should consist
of deep-rooting vegecacion requiring liccle watering.
A Landscape Archicecc would he che cest parcy co
consult regarding actual cypes or planes and planting
configuration.
. •,• ..
Stan □ard Guidelines
Eor Grading Projects
?age I 6
8.2 IRRIGATION
. . .. .. .
8.2.1 Slope irrigation should be minimized. If
automatic timing devices are utilized on
irrigation systems, ?rovisions should be made
for interrupting normal irrigation during
periods of rainfall.
8.2.2 Propert:, owners should be made aware that
. overwatering .of s-lopes is detrimental tcr slope
stability and may contribute to slope seepage,
erosion and siltation problems in the
subdivision.
. , ./• . , ··,l •• •.. . ... ,· '• ...
4• DIAMETER PERFORATED--
PIPE BAC.<ORAIN
4• DIAMETER NON-PERFORATEO-
PIPE LATERAL DRAIN
SLOPE PER PLAN
MIN.1
15' MINIMUM--
aENCHING
H/2
PROVIDE BACKDRAIN PER BACK DRAIN
DETAIL. AN ADDITIONAL BACKDRAIN
AT MIO-SLOPE WILL BE REQUIRED FOR
SLOPE IN EXCESS OF 40 FEET HIGH •
. I\E.!.-?l"!E.NSIOt,ISPER SOILS ENG.11116.ER ,,. . ..... ·-· ., ....
TYPICAL BUTTRESS OR ST ABIUZA TION FILL DETAIL
JOB NO.: DATE: FIGURE:
1
JOB NO.:
NATURAL GROUND
PROVIDE BACKDRAIN PER
BACKDRAIN DETAIL. AN
ADDITIONAL BACKDRAIN
AT MID-SLOPE WILL BE
REQUIRED FOR BACK
SLOPES IN EXCESS OF
COMPACTED FILL
PROPOSED GRADING
1
BASE WIDTH •w• DETERMINED
BY SOILS ENGINEER 40 FEET HIGH. LOCA-
TIONS-OF BACKDRAINS
AND OUTLETS PER SOILS
ENGINEER AND/OR EN-
(ilNEERiN(f GEOLOGIST·· ...
DURING GRADING.
. .... • ....
TYPICAL SHEAR KEY DETAIL
FIGURE;
2
' . .
JOB NO.:
FINAL LIMIT OF
EXCAVATION
2' MINIMUM
DAYLIGHT
LINE
OVERBURDEN
(CREEP-PRONE)
OVER EXCAVATE
FINISH PAD~
OVER EXCAVATE
3' ANO REPLACE
WITH COMPACTED
FILL
SOUND BEDROCK
TYPICAL BENCHING
----
PROVIDE BACKDRAIN PER BACKDRAIN
DETAIL. LOCATION OF BACKDRAIN ANO
-OUTLETS .. PER.6011.S. E_NGJNEER AND/OR
ENGINEERING GEOLOGIST DURING
GRADING
EQUIPMENT WIDTH (MINIMUM 15')
DAYLIGHT SHEAR KEY DETAIL
IDATE: FIGURE:
JOB NO.:
1
BENCHING FILL OVER NATURAL
FILL SLOPE-
\ -r
SURFACE OF FIRM--
EARTH MATERIAL
\_10' MIN. (INCLINEO 2'1. MIN. INTO SLOPE)
BENCHING FILL OVER CUT
FINISH FILL SLOPE
SURFACE OF FIRM
EARTH MATERIAL
FINISH CUT
SLOPE
10·
TYPICAL
15' MIN. OR STABILITY EQUIVALENT PER SOIL
ENGINEERING (INCLINED 2'1. MIN. INTO SLOPE)
BENCHING FOR COMPACTED FILL DETAIL
DATE: IFIGURE:
----
FINISH SURFACE SLOPE--.
3 FT3 MINIMUM PER LINEAL FOOT--
APPROVED FILTER ROCK'
I
2 'I, MINIM~~ GRADIENT
COMPACTED FILL
.· ..... . . ·. ·. . ..
I \ :
\_4• MINIMUM APPROVED
PERFORATED PIPE**
(PERFORATIONS DOWN)
MINIMUM 21' GRADIENT
TO OUTLET
BENCH INCLINED TOWARD
DRAIN
,4• MINIMUM DIAMETER
SOLID OUTLET PIPE
SPACED PER SOIL
ENGINEER REQUIRE-
MENTS DURING GRADING TYPICAL BENCHING
DETAIL A-A
I
COMPACTED
BACKFILL
TEMPORARY FILL LEVEL
,4• MINIMUM DIAMETER
APPROVED SOLID
OUTLET PIPE
. . ..
12" MINIMUM~ *FILTER ROCK TO MEET FOLLOWING
SPECIFICATIONS OR APPROVED EOUAL:
**APPROVED PIPE TYPE:
SCHEDULE 40 POLYVINYL CHLORIDE
(P.V.C.) OR APPROVED EOUAL.
MINIMUM CRUSH STRENGTH 1000 PSI.
SIEVE
1•
3/4"
3/8"
N0.4
N0.30
NO.SO
N0.200
TYPICAL BACKDRAIN DETAIL
JOB NO.: DATE:
PERCENTAGE PASSING
100
80-100
40-100
25--40
5-15
0-7
0-3
FIGURE:
FINISH SURFACE SLOPE -
MINIMUM 3 FT3 PER LINEAL FOOT -
OPEN GRADED AGGREGATE~
TAPE ANO SEAL AT CONTACT --
JOB NO.:
A
4• MINIMUM DIAMETER
SOLID OUTLET PIPE
SPACED PER SOIL
ENGINEER REQUIREMENTS
COMPACTED FILL
TYPICAL
BENCHING
DETAIL A-A
COMPACTED
SUPAC 8-P FABRIC OR
APPROVED EQUAL
4• MINIMUM APPROVED
PERFORATED PIPE
(PERFORATIONS DOWN)
MINIMUM 2'!. GRADIENT
TO OUTLET
BENCH INCLINED
TOWARD DRAIN
TEMPORARY FILL LEVEL
MINIMUM BACKFILL MINIMUM 4• DIAMETER APPROVED
SOLID OUTLET PIPE 12• COVER
J_
Jl-,2•--l 1 MINIMUM 'I
* NOTE: AGGREGATE TO MEET FOLLOWING
SPECIFICATIONS OR APPROVED EOUAL:
SIEVE SIZE
1 112·
1•
3/ ".
3/8"
NO. 200
PERCENTAGE PASSING
100
5--40
0-17
0-7
0-3
BACKDRAIN DETAIL (GEOFABRIC)
DATE: FIG.JAE:
6
CANYON SUBDRAIN DETAILS
TYPICAL BENCHING-
INCLINE TOWARD DRAIN
SEE DETAILS BELOW
TRENCH DETAIL
e• MINIMUM OVER LAP --li-'-'-''--~-~"""-==,T--
OPTIONAL V-DITCH DETAIL MINIMUM 6 FT 3 PER LINEAL
FOOT OF APPROVED DRAIN
MATERIAL
SUPAC 8-P FABRIC
OR APPROVED EQUAL
JOB NO.:
l, 2,· l 1 MINIMUM/
6UPAC 5-P FABRIC OR
APPROVED EQUAL
DRAIN MATERIAL SHOULD
CONSIST OF MINUS 1.5",
MINUS t•, OR MINUS .75"
CRUSHED ROCK
MINIMUM 6 FT 3 PER LINEAL FOOT
OF APPROVED DRAIN MATERIAL
ADD MINIMUM 4• DIAMETER
APPROVED PERFORATED
PIPE WHEN LARGE FLOWS
ARE ANTICIPATED
APPROVED PIPE TO BE
SCHEDULE 40 POLY-VINYL-
CHLORIDE (P.V.C.l OR
APPROVED EQUAL. MINIMUM
CRUSH STRENGTH 1000 psi.
GEOFABRIC SUBDRAIN
DATE:
FINAL GRADE
TOE OF SLOPE SHOWN
ON GRADING PLAN
FILL --------
---0"1,.0) -:-_,,,,. ,,,.1:.~ ---'-~ .....-\.." --,,,,,,,,.........-~p.\,.. .,,,,....--
------~,.. i --
--~l'-i" -----1:.~ _,,,,.
------e,1..I:. -----\l Ii ,-. _.,...:::-------,-......,----------' ,,-\)~S _,,,,. 10• TYPICAL BENCH ;,--_,,,,.
~----'-----------,,~ .-WIDTH VAR IE 6
_,,,,. --~ ~-/ ---
FILL ,,-,,-~ ~ _.dt _,,..-_,,,,.__.
----/1 __ .....-.,,,,.... COMPETENT EARTH
MATERIAL --------
------
MINIMUM
DOWNSLOPE
KEY DEPTH
I
LIMIT OF KEY
EXCAVATION
JOB NO.:
MINIMUM BASE KEY WIDTH I
TYPICAL BENCH
HEIGHT
;:>ROYIDE BACKDRAIN AS
REQUIRED PER RECOM-
MENDATIONS OF SOILS
ENGINEER DURING GRADING
WHERE NATURAL SLOPE GRADIENT IS 5: 1 OR LESS.
BENCHING IS NOT NECESSARY. HOWEVER. FILL IS
NOT TO BE PLACED ON COMPRESSIBLE OR UNSUIT-
ABLE MATERIAL.
FILL SLOPE ABOVE NATURAL GROUND DETAIL
!FIGURE: S
REMOVE ALL TOPSOIL, COLLUVIUM
ANO CREEP MATERIAL FROM
TRAllSI TION
CUT/FILL CONTACT StlOWN
ON GRADING PLAN
CUT/FILL CONTACT SHOWN
ON •AS-BUILT"
NATURAL~ ----TOPOGRAPHY -----------------------. ----CUT SLOPE
FILL ------------,._...,..,.,,,,., ---
----.,o-iE-..---___ ,,_ ... f'\:.ff' ·----
--.--f' \:. \:. V .,-------tl O C -..--'q.._--______ J
----l-A,.. ------;o\.l.-\l'l~--------4' TYPICAL j
--.---' 13,0 \ \... _,.....::--__ --_______ _J
---/ ~--_;~"..----~-'10' TYPICAL-
----1 ~--~ ... "'"'"""-f BEDROCK OR APPROVED
FOUNDATION MATERIAL
• NOTE: CUT SLOPE PORTION SHALL BE MADE
PRIOR TO PLACEMENT OF FILL
FILL SLOPE ABOVE CUT SLOPE DETAIL
JOB NO.: DATE: FIGURE:
l:!
-------
---------------
GENERAL GRADING RECOMMENDATIONS
---
CUT LOT
----ORIGINAL
-GROUND ----------------TOPSOIL, COLLUVIUM AND _... ..-
WEATHERED BEDROCK ___ _..._...
------------
------
3'
OVEREXCAVATE AND
REGRADE UNWEATHERED BEDROCK
CUT/FILL LOT (TRANSITION)
---------------------
------
_... ORIGINAL ___ _.,.,,,-GROUND
----------------
COMPACTED FILL
UNWEATHERED BEDROCK
TRANSITION LOT DETAIL
JOB NO.:
OVEREXCAVATE AND
REGRADE
FIGURE:
10
FINISHED GRADE
r CLEAR AREA FOR
FOUNDATION, UTILITIES,
AND SWIMMING POOLS
f----'-,--s--0 0
0 0 , O T 1l,
, 5. 0 1,
BUILDING
, o·
SLOPE FACE ,
STREET-
,
\_WINDROW ~------~----
5' OR BELOW DEPTH OF __j
/
JOB NO.:
DEEPEST UTILITY TRENCH
(WHICHEVER GREATER)
TYPICAL WINDROW DETAIL (EDGE VIEW)
: :·
, .. . .. .... . · .. :-.
/
..
/
GRANULAR SOIL FLOODED
TO FILL VOIDS
HORIZONTALLY PLACED
COMPACTION FILL
/ /
PROFILE VIEW
/
ROCK DISPOSAL DETAIL
DATE: I FIGURE:
11·