HomeMy WebLinkAboutPD 2022-0012; POFF ADU; PRELIMINARY GEOTECHNICAL INVESTIGATION AND RECOMMENDATIONS PROPOSED NEW ACCESSORY DWELLING UNIT; 2022-04-05
PRELIMINARY GEOTECHNICAL INVESTIGATION AND RECOMMENDATIONS
PROPOSED NEW ACCESSORY DWELLING UNIT
TO BE LOCATED AT 4374 TUOLUMNE PLACE, CARLSBAD, CALIFORNIA
EDG Project No. 226735-1
April 5, 2022
PREPARED FOR:
Alex Poff
4374 Tuolumne Place
Carlsbad, California
ENGINEERING
DESIGN GROUP
www.designgroupca.com
2121 Montiel Road, San Marcos, CA 92069
760.839.7302
Date: April 5, 2022
To: Alex Poff
4374 Tuolumne Place
Carlsbad, California 92010
Re: Proposed new, accessory dwelling unit to be located at 4374 Tuolumne Place, Carlsbad,
California.
Subject: Geotechnical Investigation and Recommendations Report
In accordance with your request and our signed proposal we have provided this preliminary geotechnical
investigation and recommendations report of the subject site for the proposed new, accessory dwelling
unit (Hereon, ADU) and typical hardscape/landscape improvements.
The findings of the investigation, earthwork recommendations and foundation design parameters are
presented in this report. In general, it is our opinion that the proposed construction, as described herein,
is feasible from a geotechnical standpoint, provided the recommendations of this report and generally
accepted construction practices are followed.
If you have any questions regarding the following report, please do not hesitate to contact our office.
Sincerely,
ENGINEERING DESIGN GROUP
Steven Norris Erin E. Rist
California GE#2590 California RCE #65122
ENGINEERING
DESIGN GROUP
www.designgroupca.com
2121 Montiel Road, San Marcos, CA 92069
760.839.7302
Table of Contents
1.0 SCOPE ................................................................................................................................................ 1
2.0 SITE AND PROJECT DESCRIPTION ...................................................................................................... 1
3.0 FIELD INVESTIGATION ....................................................................................................................... 1
4.0 SUBSURFACE CONDITIONS ............................................................................................................... 2
5.0 GEOLOGIC HAZARDS ......................................................................................................................... 2
6.0 GROUND WATER ............................................................................................................................... 3
7.0 PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS ................................................................ 4
8.0 GRADING AND EARTHWORK............................................................................................................. 5
9.0 SEISMIC DESIGN PARAMETERS ......................................................................................................... 7
10.0 SHALLOW FOUNDATIONS ................................................................................................................. 7
11.0 CORROSION AND VAPOR EMISSION ................................................................................................. 8
12.0 CONCRETE SLAB-ON-GRADE ........................................................................................................... 10
13.0 RETAINING WALLS........................................................................................................................... 11
14.0 POOL ............................................................................................................................................... 13
15.0 INFILTRATION .................................................................................................................................. 14
16.0 SURFACE DRAINAGE ........................................................................................................................ 15
17.0 LABORATORY TESTING .................................................................................................................... 15
18.0 CONSTRUCTION OBSERVATION AND TESTING ............................................................................... 15
19.0 MISCELLANEOUS ............................................................................................................................. 16
FIGURES
Site Vicinity Map .......................................................................................................................... Figure No. 1
Site Location Map ........................................................................................................................ Figure No. 2
Site Plan ....................................................................................................................................... Figure No. 3
Geologic/Geotechnical Map ........................................................................................................ Figure No. 4
Geologic/Geotechnical Cross-Section – Section A-A’ .................................................................. Figure No. 5
Test Pit Logs ....................................................................................................................... Test Pit Logs 1 – 3
APPENDICES
References .................................................................................................................................... Appendix A
General Earthwork and Grading Specifications ............................................................................ Appendix B
Laboratory Results ........................................................................................................................ Appendix C
Retaining Wall Drainage and Slab Underdrain Detail ...................................................................Appendix D
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4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
1.0 SCOPE
This report gives our geotechnical recommendations for the proposed, new ADU and associated
hardscape and landscape improvements, to be located at 4374 Tuolumne Place, Carlsbad, California. (See
Figure No. 1, "Site Vicinity Map", and Figure No. 2, "Site Location Map"). The scope of our work conducted
onsite to date has included a visual reconnaissance of the property and surrounding areas, research and
review of available city documents, review of geologic maps, a limited subsurface investigation of the
subject property, review of preliminary grading plans, laboratory tests, and preparation of this report
presenting our findings, conclusions, and recommendations.
2.0 SITE AND PROJECT DESCRIPTION
The subject property is located at 4374 Tuolumne Place, in the City of Carlsbad, California. For the
purposes of this report the lot is assumed to face west. The property is bordered to the north and south
by single-family homes, to the west by the terminus of Tuolumne Place, and to the east by Stanford Street.
The site area topography generally consists of rolling foothill terrain. The subject lot consists of a
previously graded building pad located at the western portion of the lot, flanked to the east by a
descending graded slope to the street below. At the time of this report the lot is developed with a one-
story, single-family residence, and associated hardscape and landscape improvements located at the
western, graded-pad portion of the property. Our review of available City documents indicates the subject
lot was graded in and around 1985-1986, as part of the creation of a tract subdivision (Tract 84-35 Falcon
Hills Plans by Snipes-Dye Associates). Based upon our review of site topography, there is an approximate
27-foot elevation differential across the property. Based upon our review of the preliminary project plans,
we understand the proposed development will consist of the construction of a new ADU, to be located at
the southeast portion of the property, with associated hardscape/landscape improvements.
3.0 FIELD INVESTIGATION
Our field investigation of the property consisted of a site reconnaissance, site field measurements,
observation of existing conditions on-site and on adjacent sites and a limited subsurface investigation of
soil conditions. Our subsurface investigation consisted of the visual observation of three exploratory test
pits, in the general areas of proposed construction, logging of soil types encountered, and sampling of
soils for laboratory testing. The approximate location of the test trenches is given in Figure No. 3, "Site
and Approximate Location of Test Pits".
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4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
4.0 SUBSURFACE CONDITIONS
Topsoil, fill, and weathered profiles were encountered to approximate depths between 1 and 2 feet below
adjacent grade in our exploratory test pits. Soil types encountered within our exploratory test pits are
described as follows:
4.1 Topsoil / Fill / Weathered
Topsoil, fill and weathered unsuitable materials were encountered to depths of up to 1 to 2 feet below
adjacent grade in our exploratory test pits. These materials consist of reddish brown to brown to grey to
dark grey, slightly moist, dense, silty sands and sandy silts with organics (see Figures -Test Pit Logs 1 - 3,
and Site Plan Figure No. 3). Documented fill (per original grading plans), was encountered in test pit no.
1, located in the area of the graded slope. In general, these materials (Test Pits No. 2 and 3) are not
considered suitable for the support of structures and structural improvements in their present state but
may be utilized as re-compacted fill, if necessary, provided the recommendations of this report are
followed. Unsuitable soil materials classify as SW – SM per the Unified Soil Classification System, and
based on visual observation, are considered to possess a low to medium potential for expansion.
4.2 Qvop12 – Very Old Paralic Deposits (Undivided, middle to early Pleistocene, as mapped per
Kennedy, M.P., et.al. 2007). (Mapped as Tsa in Geologic Map – Sheet 7a, obtained from City
research).
Very old paralic sandstone material was found to underlie the topsoil/fill/weathered profiles material
within the exploratory test pit excavations. These materials consist of light grey to reddish brown, slightly
moist to moist, dense to very dense, silty sandstone. These materials are considered suitable for the
support of structures and structural improvements, provided the recommendations of this report are
followed. These materials classify as SW - SM per the Unified Soil Classification System, and based upon
visual observation, are considered to possess a low potential for expansion.
Detailed logs of our exploratory test pits, as well as a depiction of their locations, please see the Figures
section attached herein.
5.0 GEOLOGIC HAZARDS
5.1 FAULTS
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4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
Our review of geologic literature pertaining to the general site area indicates the subject site is not within
a mapped Alquist-Priolo fault zone. It is our opinion that the site could be subjected to moderate to severe
ground shaking in the event of a major earthquake along any of the faults in the Southern California
region. The seismic risk at this site is similar to that of the surrounding developed area.
5.2 LIQUEFACTION, LATERAL SETTLEMENT, SUBSIDENCE
Liquefaction of cohesionless soils can be caused by strong vibratory motion due to earthquakes. Research
and historical data indicate that loose, granular soils underlain by a near-surface ground water table are
most susceptible to liquefaction, while the stability of most silty sands and clays is not adversely affected
by vibratory motion. Because of the dense nature of the soil materials underlying the site and the lack of
near surface water, the potential for lateral spreading, liquefaction, subsidence or seismically induced
dynamic settlement at the site is considered low. The effects of seismic shaking can be reduced by
adhering to the most recent edition of the California Building Code and current design parameters of the
Structural Engineers Association of California.
5.3 TSUNAMI
Tsunami are sea waves generated by submarine earthquakes, landslides, or volcanic activity. Submarine
earthquakes are common along the edge of the Pacific Ocean and coastal areas are subject to potential
inundation by tsunami. Most of the tsunamis recorded on the San Diego Bay tidal gauge have only been
a few tenths of a meter in height. The possibility of a destructive tsunami along the San Diego coastline is
considered low. Tsunami or storm waves (associated with winter storms), even in conjunction with high
tides, do not have the potential for inundations of the site.
5.4 SLOPE STABILITY
As part of the preparation of this report we have reviewed geologic maps of the subject area. Our review
of geologic maps does not indicate landslide deposits at the area in and around the subject site.
6.0 GROUND WATER
Static ground water was not encountered during our limited subsurface investigation. However, perched
groundwater conditions can develop, should be expected, and change over time, where no such condition
previously existed and can have a significant impact. Waterproofing membrane shall be specifically
detailed by waterproofing consultant. If groundwater conditions are encountered during site excavations,
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4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
a slab underdrain system may be required. Trenches below slab should be detailed with perimeter and
trench cut-off walls keyed into competent material.
7.0 PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS
Based upon our review of preliminary project plans, we understand the proposed improvements will
include a new, ADU and associated hardscape & landscape improvements. In general, it is our opinion
that the proposed new structures and improvements, as discussed and described herein, are feasible from
a geotechnical standpoint, provided the recommendations of this report and all applicable codes are
followed.
• Our review of the project grading plan indicates the new pad will be formed with new fill slopes
at the eastern portion of the pad, as well as cuts & retaining walls at the northern and western
portions of the building pad.
• Our review of the project grading plan indicates cuts on the order of 3 feet in the area of proposed
building and 5 feet in the area of the building pad.
• In areas of proposed accessory dwelling unit, we anticipate the removal of unsuitable profiles as
part of grading operation for the creation of the new building pad.
• Proposed grading plans indicate new pad will include a cut-fill transition. New shallow foundations
and slab-on-grade floors for ADU shall be founded in competent re-compacted materials, an
undercut is anticipated at western portions of proposed ADU pad.
• We anticipate new shallow foundations and new slab-on-grade floors, founded on re-compacted
fill material, for the proposed improvements.
• Proposed retaining wall footings shall extend into competent paralic material. Deepening of new
wall foundations at some locations (eastern portions), is anticipated.
• Grading plans from original grading operations indicate a buttress fill reaches the subject
property. It appears a subdrain extends to the adjacent property to the west. If during
construction, the subdrain system is encountered, all work shall stop and subdrain system shall
not be damaged and shall be protected in place.
• Any changes in the proposed design should be reviewed by this office for any revisions to the
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4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
recommendations herein.
8.0 GRADING AND EARTHWORK
Based upon our review of the preliminary grading plan, in the area of the proposed ADU, we anticipate
grading and earthwork operations will include the creation of a new building pad, which will include new
graded fill slopes, and site retaining walls. Grading plans from original grading operations indicate a
buttress fill reaches the subject property. It appears a subdrain extends to the adjacent property to the
west. If during construction, the subdrain system is encountered, all work shall stop and subdrain system
shall not be damaged and shall be protected in place. All grading shall be done in accordance with the
recommendations below as well as Appendix B of this report and the standards of county and state
agencies, as applicable.
8.1 Site Preparation
Prior to any grading, the areas of proposed improvements should be cleared of surface and subsurface
debris (including organic topsoil, vegetative and construction debris). Removed debris should be properly
disposed of off-site prior to the commencement of any fill operations. Construction debris should not
generally be mixed with fill soils. Holes resulting from the removal of debris, existing structures, or other
improvements, should be filled, and compacted.
8.2 Removals
In areas of new proposed structures, topsoil/any undocumented fill/weathered profiles found to mantle
the site, are not suitable for the structural support of buildings or structural improvements in their present
state. We anticipate the removal of topsoil/unsuitable materials as part of grading operations for the
creation of the building pad. We anticipate grading will consist in the removal of all unsuitable fill and
weathered soil to competent material, the creation of a keyway at the toe of all new fill slopes, canting
and scarification of keyway bottom, benching into competent material, undercutting, placement, and re-
compaction of fill material per Appendix B. New fills for the proposed pad and driveway slopes should be
re-compacted to a minimum of 90 percent relative compaction (ASTM D1557 – latest edition).
8.3 Transitions
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4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
All settlement sensitive improvements (including but not limited to building structures, retaining walls,
driveways, etc.), should be constructed on a uniform building pad. We anticipate undercutting will be
necessary at northern and western portions of the new building pad.
Undercuts should extend a minimum of 5 feet (or to a distance at least equal to depth of fill) beyond the
footprint of the proposed structures (including exterior columns) and settlement sensitive improvements.
Undercuts shall be made a minimum of 3 feet, or to a minimum depth of half the depth of deepest fill.
Undercut bottoms may require sloping at a minimum 1% to daylight and construction of a subdrain
(reference Appendix B). We anticipate building foundations will be founded on competent re-compacted
material. This condition needs to be verified in the field by a representative of our firm prior to placement
of fill or improvements during site grading operations
8.4 Fills/Backfill
All fill/backfill material should be cleaned of loose debris and oversize material (material more than 6
inches in diameter), be brought to approximately +2% of optimum moisture content, and re-compacted
to at least 90 percent relative compaction (based on ASTM D1557 – latest edition). Fills should generally
be placed in lifts not exceeding 6 - 8 inches in thickness. Fill should be tested for relative density every 2
vertical feet at a minimum.
Import material is not anticipated. If import material is utilized, imported soils should have a very low
potential for expansion (E.I. < 20), free of debris and organic matter. Prior to importing soils, they should
be visually observed, sampled, and tested at the borrow pit area to evaluate soil suitability as fill. Onsite
materials are suitable for re-use as fill material during grading operations provided, they are free of
contamination (construction debris and organics) and oversize material in excess of 6 inches in diameter
(oversize material is generally not anticipated). Utility trenches should be properly backfilled in
accordance with the latest edition of Green Book standards.
8.5 Slopes
Where new slopes are constructed, permanent slopes may be cut to a face ratio of 2:1 (horizontal to
vertical). Permanent fill slopes shall be placed at a maximum 2:1 slope face ratio. All temporary cut slopes
shall be excavated in accordance with OSHA requirements and OSHA Alternative Sloping Plans and shall
not undermine adjacent properties, public improvements, or any structures without proper shoring of
excavation and/or structures. Subsequent to grading, planting or other acceptable cover should be
provided to increase the stability of slopes, especially during the rainy season (October thru April).
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4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
8.6 Flatwork
In the areas of proposed exterior flatwork we recommend, the upper 12 inches of subgrade or finish grade
shall be ripped a minimum of 12 inches, moisture conditioned to near optimum moisture content and
compacted to 90% minimum relative compaction (ASTM D1557 – latest edition).
(Please see our CONCRETE SLAB-ON-GRADE section for additional flatwork recommendations, and our
INFILTRATION section for additional paver recommendations).
9.0 SEISMIC DESIGN PARAMETERS
9.1 2019 CBC Seismic Design Parameters
Site Class D
Seismic Design Category D
Seismic Risk Category II
Spectral Response Coefficients
SS (g) 0.977
S1 (g) 0.358
SMS (g) 1.172
SDS (g) 0.781
10.0 SHALLOW FOUNDATIONS
The following design parameters may be utilized for new foundations founded on competent re-
compacted material.
10.1 Footings bearing uniformly in competent material may be designed utilizing maximum allowable
soils pressure of 2,000 psf.
10.2 Bearing values may be increased by 33% when considering wind, seismic, or other short
duration loadings.
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4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
10.3 The parameters in the table below should be used as a minimum for designing new footing width
and depth below lowest adjacent grade into competent material. Footing depths are to be
confirmed in the field by a representative of Engineering Design Group prior to the placement of
form boards, steel, and removal of excavation equipment.
No. of Floors
Supported
Minimum Footing Width *Minimum Footing Depth Below
Lowest Adjacent Grade
1 15 inches 18 inches
2 15 inches 18 inches
3 18 inches 24 inches
*Footings are anticipated to be founded in competent re-material. Deepened as
necessary for distance to daylight purposes.
10.4 All footings founded into competent material should be reinforced with a minimum of two #4
bars at the top and two #4 bars at the bottom (3 inches above the ground). For footings over 30
inches in depth, additional reinforcement, and possibly a stemwall system will be necessary, and
should be reviewed by project structural engineer prior to construction.
10.5 All isolated spread footings should be designed utilizing the above given bearing values and
footing depths and be reinforced with a minimum of #4 bars at 12 inches o.c. in each direction (3
inches above the ground). Isolated spread footings should have a minimum width and depth of
24 inches.
10.6 For footings adjacent to slopes a minimum of 10 feet horizontal setback in competent material or
properly compacted fill should be maintained. A setback measurement should be taken at the
horizontal distance from the bottom of the footing to slope daylight. Where this condition cannot
be met, it should be brought to the attention of the Engineering Design Group for review.
10.7 All excavations should be performed in general accordance with the contents of this report,
applicable codes, OSHA requirements and applicable city and/or county standards.
10.8 All foundation subgrade soils and footings shall be pre-moistened to 2% over optimum to a
minimum of 18 inches in depth prior to the pouring of concrete.
11.0 CORROSION AND VAPOR EMISSION
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4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
11.1 Resistivity and chloride testing of onsite samples from our subsurface investigation was
conducted to evaluate corrosion potential to proposed improvements. Tests performed indicate
that soils classify, according to ACI 318 standard, as category C1, and based upon laboratory
results are considered mild to moderately corrosive to buried metals. Test results are included in
Appendix C of this report. The project structural engineer to note increased concreted protection
requirements for corrosive environments, as applicable.
11.2 Laboratory testing of onsite samples for water soluble sulfates, indicate soils classify, according
to ACI 318 standard, as category S0, mildly to moderately corrosive due to sulfate attack to
concrete structures.
11.3 For non-moisture sensitive areas, we recommend concrete with a minimum compressive strength
of 2,500 psi minimum.
11.4 Buried metals shall be protected, and a corrosion engineer should be consulted for appropriate
mitigation recommendations. EDG is not an expert in corrosion protection. Design
recommendations for the protection of improvements from corrosive environment shall be
provided by the corrosion consultant.
11.5 Where onsite improvements propose the use of reclaimed water, onsite soils are to be considered
highly corrosive to buried metals. Precautions should be taken to protect all buried metals.
11.6 Slab Underlayment: We recommend the following beneath proposed slab-on-grade floors.
11.6.a. For moisture-sensitive areas, we recommend a vapor barrier.
11.6.b. The slab underlayment for moisture-sensitive areas consists of a vapor barrier layer (15
mil) placed below the upper one-inch of sand. The vapor barrier shall meet the following
minimum requirements: Permeance of less than 0.01 perm [grains/(ft²hr in/Hg)] as tested
in accordance with ASTM E 1745 Section 7.1 and strength per ASTM 1745 Class A.
11.6.c. In areas of level slab on grade floors, we recommend a one-inch layer of coarse sand
material, Sand Equivalent (S.E.) greater than 50 and washed clean of fine materials,
should be placed beneath the slab in moisture-sensitive areas, above the vapor barrier.
There shall be not greater than a 2-inch difference across the sand layer.
11.6.d. The vapor barrier should extend down the interior edge of the footing excavations a
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4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
minimum of 6 inches. The vapor barrier should lap a minimum of 8 inches, sealed along
all laps with the manufacturer’s recommended adhesive. Beneath the vapor barrier a
uniform layer of 3 inches of pea gravel is recommended under the slab in order to more
uniformly support the slab, help distribute loads to the soils beneath the slab, and act as
a capillary break.
11.7 The project waterproofing consultant should provide all slab underdrain, slab sealers and various
other details, specifications and recommendations (i.e. Moiststop and Linkseal) at areas of
potential moisture intrusion. Engineering Design Group accepts no responsibility for design or
quality control of waterproofing elements of the building.
12.0 CONCRETE SLAB-ON-GRADE
We anticipate all new concrete slab-on-grade floors will be placed on competent re-compacted material.
Where new slabs are proposed, we recommend the following as the minimum design parameters.
12.1 Interior concrete slab-on-grade: Minimum thickness of 5 inches and reinforced with #4 bars at
18 inches o.c. placed at the midpoint of the slab.
Driveways: Minimum thickness of 5 inches and reinforced with #4 bars at 18 inches o.c. placed
at the midpoint of the slab.
Exterior Flatwork: Minimum thickness of 4 inches and reinforced with #3 bars at 16 inches o.c.
at the midpoint of the slab.
12.1.a. Slump: Between 3 and 4 inches maximum.
12.1.b. Aggregate Size: ¾ - 1 inch.
12.2 Adequate control joints should be installed to control the unavoidable cracking of concrete that
takes place when undergoing its natural shrinkage during curing. The control joints should be well
located to direct unavoidable slab cracking to areas that are desirable by the designer.
12.3 All required fills used to support slabs, should be placed in accordance with the GRADING AND
EARTHWORK section of this report and the attached Appendix B, and compacted to 90 percent
relative compaction (Modified Proctor Density, ASTM D-1557 – Latest Edition).
12.4 Concrete should be poured during cool (40 – 65 degrees) weather if possible. If concrete is
poured in hotter weather, a set retarding additive should be included in the mix, and the slump
kept to a minimum.
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4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
12.5 All subgrade soils to receive concrete slabs and flatwork are to be pre-soaked to 2 percent over
optimum moisture content, to a minimum depth of 18 inches.
12.6 Exterior concrete flatwork, due to the nature of concrete hydration and minor subgrade soil
movement, are subject to normal minor concrete cracking. To minimize expected concrete
cracking, the following additional recommendations should be implemented:
12.6.a. Exterior concrete flatwork should be poured with a 10-inch-deep thickened edge.
Flatwork adjacent to top of a slope should be constructed with an outside footing to attain
a minimum of 7 feet distance to daylight.
12.6.b. Exterior concrete flatwork should be constructed with tooled joints creating concrete
sections no larger than 225 square feet. For sidewalks, the maximum run between joints
should not exceed 5 feet. For rectangular shapes of concrete, the ratio of length to width
should generally not exceed 0.6 (i.e., 5 ft. long by 3 ft. wide). Joints should be cut at
expected points of concrete shrinkage (such as male corners), with diagonal
reinforcement placed in accordance with industry standards.
12.6.c. Isolation joints should be installed at exterior concrete where exterior concrete is poured
adjacent to existing foundations.
12.6.d. Drainage adjacent to exterior concrete flatwork should direct water away from the
improvements. Concrete subgrade should be sloped and directed to the collective
subdrain system, such that water is not trapped below the flatwork.
12.7 The recommendations set forth herein are intended to reduce cosmetic nuisance cracking. The
project concrete contractor is ultimately responsible for concrete quality and performance and
should pursue a cost-benefit analysis of these recommendations, and other options available in
the industry, prior to the pouring of concrete.
13.0 RETAINING WALLS
Site retaining walls are anticipated as part of the proposed development. New site retaining walls up to 6
feet may de designed and constructed in accordance with the following recommendations and minimum
design parameters.
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4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
13.1 Retaining wall footings should be designed in accordance with the allowable bearing criteria given
in the Foundations section of this report and should maintain minimum footing depths outlined
in the Foundations section of this report. Any retaining wall footings are to be placed on
competent material. Where cut-fill transitions may occur, alternative detailing may be provided
by the Engineering Design Group on a case-by-case basis.
13.2 Unrestrained cantilever retaining walls should be designed using an active equivalent fluid
pressure of 35 pcf. This assumes that granular, free draining material with low potential for
expansion (E.I. <50) will be used for backfilling, and that the backfill surface will be level. Where
soil with potential for expansion is not low (E.I. > 50) a new active fluid pressure will be provided
by the project soils engineer. Backfill materials should be considered prior to the design of the
retaining walls to ensure accurate detailing. We anticipate onsite material may be utilized as
retaining wall backfill, additional Expansion Index Testing may be conducted during site grading
to confirm suitability.
13.3 Where the backfill behind the wall is sloped at a maximum slope of 2:1 (H:V) an active
equivalent fluid pressure of 55 pcf, shall be utilized.
13.4 Any other surcharge loadings shall be analyzed in addition to the above values. These surcharge
loads shall include foundations, construction equipment, vehicular traffic, etc.
13.5 If the tops of retaining walls are restrained from movement, they should be designed for a
uniform at-rest soil pressure of 60 psf.
13.6 Retaining walls shall be designed for additional lateral forces due to earthquake, where required
by code, utilizing the following design parameters.
13.6.a. For unrestrained, retaining walls with level backfill, we recommend an additional seismic
load of 15H applied as a uniform load. The resultant load should be applied a distance of
0.5H from the bottom of the footing.
13.6.b. For unrestrained, retaining walls with sloped backfill up to 2:1 slope, we recommend an
additional seismic load of 18H applied as a uniform load. The resultant load should be
applied a distance of 0.5H from the bottom of the footing.
13.6.c. The unit weight of 125 pcf for the onsite soils may be utilized.
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4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
13.6.d. The above design parameters assume unsaturated conditions. Retaining wall designs for
sites with a hydrostatic pressure influence (i.e groundwater within depth of retaining wall
or waterfront conditions) will require special design considerations and should be brought
to the attention of Engineering Design Group.
13.7 Passive soil resistance may be calculated using an equivalent fluid pressure of 300 pcf. This value
assumes that the soil being utilized to resist passive pressures extends horizontally 2.5 times the
height of the passive pressure wedge of the soil. Where the horizontal distance of the available
passive pressure wedge is less than 2.5 times the height of the soil, the passive pressure value
must be reduced by the percent reduction in available horizontal length.
13.8 A coefficient of friction of 0.32 between the soil and concrete footings may be utilized to resist
lateral loads in addition to the passive earth pressures above.
13.9 All walls shall be provided with adequate back drainage to relieve hydrostatic pressure, and be
designed in accordance with the minimum standards contained in the "Retaining Wall Drainage
Detail", Appendix D. The waterproofing elements shown on our details are minimums and are
intended to be supplemented by the waterproofing consultant and/or architect. The
recommendations should be reviewed in consideration of proposed finishes and usage, especially
at the proposed basement levels, performance expectations and budget.
13.10 If deemed necessary by the project owner, based on the above analysis, and waterproofing
systems can be upgraded to include slab under drains and enhanced waterproofing elements.
13.11 In moisture sensitive areas (i.e., interior living space where vapor emission is a concern), in our
experience poured-in-place concrete provides a surface with higher performance-repairability of
below grade waterproofing systems. The developer should consider the cost-benefit of utilizing
cast in place building retaining walls in lieu of masonry as part of the overall construction of the
commercial structure. Waterproofing at any basement floors is recommended in areas of
moisture sensitive floor finishes.
14.0 POOL
We understand no pool is proposed as part of the proposed development. Where a future pool may be
proposed as part of site development, Engineering Design Group shall provide additional pool
recommendations.
Poff Residence Page No. 14
4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
15.0 INFILTRATION
At the time of this report, bioretention/infiltration facilities are not proposed for this project. If
bioretention/infiltration facilities are proposed, they shall be designed to maintain sufficient horizontal
and vertical offset to the future structures so as not to create a groundwater condition. Infiltration
facilities proposed within a 10-foot horizontal distance to a moisture sensitive structure should be lined
with an impervious barrier, within the 10-foot zone. In cases where there is a vertical offset, wherein the
bottom of the infiltration basin is detailed above the finish floor of the building, the impervious barrier
should line the bottom of the basin or paver subgrade, such that the cumulative distance of the horizontal
and vertical offset equal at a minimum the depth of the subterranean finish pad.
Infiltration facilities should be offset from the top and toes of any slopes steeper than a 3:1 or lined with
an impervious barrier. At tops of slopes minimum horizontal distance of 10 feet or a horizontal distance
equal to the height of the slope, measured from the edge of infiltration basin to slope, up to a maximum
of 40 horizontal feet. At the toe of new fill slopes infiltration facilities shall maintain a minimum 10 feet
horizontal offset to not undermine the stability of the slope. New retaining walls to support proposed
slope might be necessary where infiltration/retention basins are located at toes of slopes.
Where pervious paver subgrade is located adjacent to the building, paver subgrade shall be sloped away
at 2%, and should be lined with an impervious liner a minimum horizontal distance of 5 feet from building.
Permeable paver subgrade shall be sloped 2% minimum to a perforated subdrain, gravel filled (1cf/ft),
wrapped in a filter fabric, permeable pavers shall be detailed with reinforced concrete edge restraints that
extend minimum 4 inches below reservoir depth, and horizontal restraints. Where permeable paver
driveways are utilized in sloped conditions, cut-off wall detailing should also be anticipated. In addition to
the above details, specific paver detailing should be detailed and constructed per the minimum
recommendations of the specific paver manufacturer as well as the Interlocking Concrete Paver Institute
including minimum bedding specifications, base and subgrade requirements, installation tolerances, and
drainage, etc. Where runoff and storm water is directed over permeable pavements and water is
anticipated to flow through pavers into an aggregate base near and adjacent to foundations, basements
or other structures, additional detailing shall include systems to control and to prevent subsurface flow
beneath the building. Generally, these systems, detailed as part of the specific building construction plans,
may include the cut-off walls and underdrains.
Proper surface drainage and irrigation practices will play a significant role in the future performance of
the project. Please note in the Corrosion and Vapor Emission section of this report for specific
recommendations regarding water to cement ratio for moisture sensitive areas should be adhered. The
project architect and/or waterproofing consultant shall specifically address waterproofing details.
Poff Residence Page No. 15
4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
16.0 SURFACE DRAINAGE
Adequate drainage precautions at this site are imperative and will play a critical role on the future
performance of the proposed improvements. Under no circumstances should water be allowed to pond
against or adjacent to tops of slopes and/or foundation walls.
The ground surface surrounding proposed improvements should be relatively impervious in nature, and
slope to drain away from the structure in all directions, with a minimum slope of 2% for a horizontal
distance of 10 feet (where possible). Area drains or surface swales should then be provided in low spots
to accommodate runoff and avoid any ponding of water. Any french drains, backdrains and/or slab
underdrains shall not be tied to surface area drain systems. Roof gutters and downspouts shall be installed
on the new and existing structures and tightlined to the area drain system. All drains should be kept clean
and unclogged, including gutters and downspouts. Area drains should be kept free of debris to allow for
proper drainage.
Over watering can adversely affect site improvements and cause perched groundwater conditions.
Irrigation should be limited to only the amount necessary to sustain plant life. Low flow irrigation devices
as well as automatic rain shut-off devices should be installed to reduce over watering. Irrigation practices
and maintenance of irrigation and drainage systems are an important component to the performance of
onsite improvements.
During periods of heavy rain, the performance of all drainage systems should be inspected. Problems
such as gullying or ponding should be corrected as soon as possible. Any leakage from sources such as
water lines should also be repaired as soon as possible. In addition, irrigation of planter areas, lawns, or
other vegetation, located adjacent to the foundation or exterior flat work improvements should be strictly
controlled or avoided.
17.0 LABORATORY TESTING
Laboratory tests were performed on samples of onsite material collected during our subsurface
investigation. Test results are attached as Appendix C.
18.0 CONSTRUCTION OBSERVATION AND TESTING
The recommendations provided in this report are based on subsurface conditions disclosed by the
Poff Residence Page No. 16
4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
investigation and our general experience in the project area. Interpolated subsurface conditions should
be verified in the field during construction. The following items shall be conducted prior/during
construction by a representative of Engineering Design Group in order to verify compliance with the
geotechnical and civil engineering recommendations provided herein, as applicable. The project
structural and geotechnical engineers may upgrade any condition as deemed necessary during the
development of the proposed improvement(s).
18.12 Review of final approved grading and structural plans prior to the start of work for compliance
with geotechnical recommendations.
18.13 Attendance of a pre-grade/construction meeting prior to the start of work.
18.14 Observation of keyways, subgrade and excavation bottoms.
18.15 Testing of any fill placed, including retaining wall backfill and utility trenches.
18.16 Observation of footing excavations prior to steel placement and removal of excavation
equipment.
18.17 Field observation of any "field change" condition involving soils.
18.18 Walk through of final drainage detailing prior to final approval.
The project soils engineer may at their discretion deepen footings or locally recommend additional steel
reinforcement to upgrade any condition as deemed necessary during site observations. Engineering
Design Group shall, prior to the issuance of the certificate of occupancy, issue in writing that the above
inspections have been conducted by a representative of their firm, and the design considerations of the
project soils report have been met. The field inspection protocol specified herein is considered the
minimum necessary for Engineering Design Group to have exercised due diligence in the soils engineering
design aspect of this building. Engineering Design Group assumes no liability for structures constructed
utilizing this report not meeting this protocol.
Before commencement of grading the Engineering Design Group will require a separate contract for
quality control observation and testing. Engineering Design Group requires a minimum of 48 hours’ notice
to mobilize onsite for field observation and testing.
19.0 MISCELLANEOUS
It must be noted that no structure or slab should be expected to remain totally free of cracks and minor
signs of cosmetic distress. The flexible nature of wood and steel structures allows them to respond to
Poff Residence Page No. 17
4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
movements resulting from minor unavoidable settlement of fill or natural soils, the swelling of clay soils,
or the motions induced from seismic activity. All of the above can induce movement that frequently
results in cosmetic cracking of brittle wall surfaces, such as stucco or interior plaster or interior brittle slab
finishes.
Data for this report was derived from surface and subsurface observations at the site and knowledge of
local conditions. The recommendations in this report are based on our experience in conjunction with the
limited soils exposed at this site. We believe that this information gives an acceptable degree of reliability
for anticipating the behavior of the proposed improvement; however, our recommendations are
professional opinions and cannot control nature, nor can they assure the soils profiles beneath or adjacent
to those observed. Therefore, no warranties of the accuracy of these recommendations, beyond the limits
of the obtained data, is herein expressed or implied. This report is based on the investigation at the
described site and on the specific anticipated construction as stated herein. If either of these conditions
is changed, the results would also most likely change. Man-made or natural changes in the conditions of
a property can occur over a period. In addition, changes in requirements due to state-of-the-art
knowledge and/or legislation are rapidly occurring. As a result, the findings of this report may become
invalid due to these changes. Therefore, this report for the specific site, is subject to review and not
considered valid after a period of one year, or if conditions as stated above are altered.
It is the responsibility of the owner or his/her representative to ensure that the information in this report
be incorporated into the plans and/or specifications and construction of the project. It is advisable that a
contractor familiar with construction details typically used to deal with the local subsoil and seismic
conditions be retained to build the structure. If you have any questions regarding this report, or if we can
be of further service, please do not hesitate to contact us. We hope the report provides you with necessary
information to continue with the development of the project.
FIGURES
FIGURE 1
Vicinity Map
Site Location
Project: Poff Residence
Address: 4374 Tuolumne Place, Carlsbad, California
EDG Project No:226735-1
ENGINEERING
DESIGN GROUP
www.designgroupca.com
2121 Montiel Road, San Marcos, CA 92069
760.839.7302
FIGURE 2
Site Map
Site Location
Project: Poff Residence
Address: 4374 Tuolumne Place, Carlsbad, California
EDG Project No:226735-1
ENGINEERING
DESIGN GROUP
www.designgroupca.com
2121 Montiel Road, San Marcos, CA 92069
760.839.7302
FIGURE 3
Site and Approximate Location
of Exploratory Test Pits
Not to Scale
TP1
TP2
TP3
Project: Poff Residence
Address: 4374 Tuolumne Place, Carlsbad, California
EDG Project No:226735-1
ENGINEERING
DESIGN GROUP
www.designgroupca.com
PROPOSED
717sf ADU
GAS METER
IOOA PANEL
&METER
2121 Montiel Road, San Marcos, CA 92069
760.839.7302
1/ 1/
STAK "
o.o·
(El FENCE LINE
4374 TUOLUMNE PLACE
CARLSBAD, CALIFORNIA 92010
226735-1
3-29-2022 FIGURE NO.:
GRAVEL BAGS OVERLAP
ONTOCURB )
GAf> BETIVEEN BAGS
ACTS AS SPILLWAY
GRAVEL BAG DETAIL (SE-6)
GRAVEL BAG SECTION (SE-8) ,,/
\0\ /
vO:.-/ ·
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GEOLOGIC I GEOTECHNICAL MAP
POFF RESIDENCE -PROPOSED ADU
EXIST. SL()Pf I
1:n1\
I
• ' \ I
I . . .
GEOLOGJC/GEOTECHNICAL MAP '
ENGINEERING
DESIGN GROUP
www.designgroupca.com
2121 Montiel Road, San Marcos, CA 92069
760.839.7302
30 0 30 60 90 ---~---~-----1 ____ 1---~, I--I
SCALE 1• = JO FT
LEGEND
@;] ( )
T2 ()
A_I _IA
JOB NAME:
JOB ADDRESS:
JOB NO.:
DATE:
Topsoil and Fill (buried units shown in
parentheses)
Very Old Paralic Deposits (As Mapped per
Kennedy, et.al. 2007)
Exploratory Test Pit -Per Original Report
Geologic Contact (In section view)
Approximate Property
Line Boundary
Section
Approximate Limits of
Proposed Improvements
Approximate Limits of
Remedial Grading
(Section View)
POFF RESIDENCE -PROPOSED ADU
4
4374 TUOLUMNE PLACE
CARLSBAD, CALIFORNIA 92010
226735-1
3-29-2022 FIGURE NO.:
360.0
350.0
340.0
330.0
320.0
XISTING SLOPE,
TO REMAIN
ROPOSED
STRUCTURE
AREA OF REMEDIAL GRADIN
(INCLUDING UNDERCUTS,
BENCHING, BACKFILLING
ROPOSED STRUCTURE
BEYOND SECTION
T2*
APPROXIMATE AND
PROJECTED LOCATION
OF TEST PITS TYP.
315.0 ,__,__-----+----------------+----------------+----------------+--------------+--------------+----------------+-
0+00.00 0+25.00 0+50.00
*APPROXIMATE AND PROJECTED LOCATION OF TEST PITS IN SECTION VIEW
ENGINEERING
DESIGN GROUP
www.designgroupca.com
2121 Montiel Road, San Marcos, CA 92069
760.839.7302
0+75.00
SECTION A -A'
SCALE: 1 "= 10 '-0"
1 +00.00 1 +25.00 1+50.
JOB NAME: POFF RESIDENCE -PROPOSED ADU
JOB ADDRESS:
JOB NO.:
DATE: 5
Project Name: Poff Residence TEST PIT LOG NO. 1
EDG Project 226735-1 Number:
Location: See Figure 3 -Location of Test Pits Sheet 1 of 1
Date(s) Total Depth: Groundwater
Excavated: 3/10/2022 3.5' Level: Not encountered
Logged By: ER/RM/AB Approx. Surface Backfilled
Elev. Finished Grade -332' (date) Same Day
Excavation
Method: Hand Dug
Soil Type Depth Material Description and Notes ucsc Sample
TOPSOIL FILL WEATHERED
A 0-2.5' Orangish brown to grey, slightly moist, mottled, dense, silty sand/sandy silt, SW-SM Bulk
with roots
VERY OLD PARALIC DEPOSITS
B 2.5' -3.5' Light grey, moist, dense to very dense, silty sandstone SW-SM --
GRAPHIC REPRESENTATION
FT. B.A.G. FG '\JI ® \V -
~
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\
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6 • '~' "''~ :f·.: '·:"~ ... .:-~ ,
4 ,---1/,~l-k:~
5
6
Project Name: Poff Residence TEST PIT LOG NO. 2
EOG Project 226735-1 Number:
Location: See Figure 3 -Location of Test Pits Sheet 1 of 1
Date(s) Total Depth: Groundwater
Excavated: 3 I 10 / 2022 1.5' Level: Not encountered
Logged By: ER/ RM/ AB Approx. Surface Backfilled
Elev. Finished Grade -326' (date) Same Day
Excavation
Method: Hand Dug
Soil Type Depth Material Description and Notes ucsc Sample
TOPSOIL, FILL, WEATHERED
A 0-1.0' Greyish:brown to orangish brown, moist, dense, silty sand/sandy silt. SW-SM Bulk
VERY OLD PARALIC DEPOSITS
B 1.0' -1.5' Orangish brown, moist, dense to very dense, silty sandstone. Hand auger SW-SM --
refusal at bottom.
GRAPHIC REPRESENTATION
FT. B.A.G. FG --.v ® \V
1 \ \
l-~li .•\&
~ ' :\ :\ \. \-\' IN/ I I
2 ~
·:;;s· :£.ff i'>v,' .,;: •• •• "'
~1JL~~
3
4
5
6
Project Name: Poff Residence TEST PIT LOG NO. 3
EDG Project 226735-1 Number:
Location: See Figure 3 -Location of Test Pits Sheet 1 of 1
Date(s) Total Depth: Groundwater
Excavated: 3/10/2022 3.5' Level: Not encountered
Logged By: ER/ RM/ AB Approx. Surface Backfilled
Elev. Finished Grade -327' (date) Same Day
Excavation
Method: Hand Dug
Soil Type Depth Material Description and Notes ucsc Sample
TOPSOIL, FILL, WEATHERED
A 0-2.0' Reddish brown to dark greyish brown, mottled, moist, dense to very dense, SW-SM Bulk
roots/organics, scattered small cobbles.
VERY OLD PARALIC DEPOSITS
B 2.0' -3.5' Orangish brown, moist, dense to very dense, silty sandstone. SW-SM --
Hand ~-~ger refusal at bottom.
GRAPHIC REPRESENTATION
FT. B.A.G. FG
1
2
3
4
5
6
APPENDIX A
REFERENCES
1. BHA Inc., Grading Plans for Poff ADU, received 2-16-2022.
2. California Geological Survey, Probabilistic Seismic Hazards Mapping Ground Motion Page.
3. California Department of Conservation, Division of Mines and Geology, Fault Rupture Zones in California, Special
Publication 42, Revised 1990.
4. California Department of Conservation, Division of Mines and Geology, DMG Open-File Report 95-04, Landslide
Hazards in the Northern Part of the San Diego County Metropolitan Area, San Diego County, California –
Landslide Hazard Identification Map No. 35 – Oceanside and San Luis Rey Quadrangle (Plate 35A), dated 1995.
5. Day, Robert W. 1999. Geotechnical and Foundation Engineering Design and Construction. McGraw Hill.
6. Greensfelder, R.W., 1974 Maximum Credible Rock Acceleration from Earthquakes in California Division of Mines
and Geology, Map Sheet 23.
7. Kennedy, Michael M.P., Tan, S.S., et. al., Geologic Map of the Oceanside 30’x60’ Quadrangle, California, dated
2007.
8. Lee, L.J., 1977, Potential foundation problems associated with earthquakes in San Diego, in Abbott, P.L. and
Victoria, J.K., eds. Geologic Hazards in San Diego, Earthquakes, Landslides, and Floods: San Diego Society of
Natural History John Porter Dexter Memorial Publication.
9. Marcela & Logan Architects, Plans for Poff ADU – Carlsbad, dated August 12, 2021.
10. Ploessel, M.R. and Slossan, J.E., 1974 Repeatable High Ground Acceleration from Earthquakes: California
Geology, Vol. 27, No. 9, P. 195-199.
11. Snipes-Dye Associates, Grading Plan for: Carlsbad Tract 84-35 Falcon Hills, dated 8-28-85.
12. State of California, Fault Map of California, Map No. 1, Dated 1975.
13. State of California, Geologic Map of California, Map No. 1, Dated 1977.
14. Structural Engineers Association of Southern California (SEAOSC) Seismology Committee, Macroseminar
Presentation on Seismically Induced Earth Pressure, June 8, 2006.
15. U.S. Army Corps of Engineers, Coast of California Storm and Tidal Waves Study, Shoreline Movement Data
Report, Portuguese Point to Mexican Border, dated December 1985.
16. U.S. Army Corps of Engineers, Coast of California Storm and Tidal Waves Study, Coastal Cliff Sediments, San
Diego Region (CCSTWS 87-2), dated June 1985.
17. Van Dorn, W.G., 1979 Theoretical aspects of tsunamis along the San Diego coastline, in Abbott, P.L. and Elliott,
W.J., Earthquakes and Other Perils: Geological Society of America field trip guidebook.
18. Various Aerial Photographs.
APPENDIX B
General Earthwork and Grading Specifications
1.0 General Intent
These specifications are presented as general procedures and recommendations for grading and
earthwork to be utilized in conjunction with the approved grading plans. These general earthwork
and grading specifications are a part of the recommendations contained in the geotechnical report
and shall be superseded by the recommendations in the geotechnical report in the case of conflict.
Evaluations performed by the consultant during the course of grading may result in new
recommendations which could supersede these specifications or the recommendations of the
geotechnical report. It shall be the responsibility of the contractor to read and understand these
specifications, as well as the geotechnical report and approved grading plans.
2.0 Earthwork Observation and Testing
Prior to commencement of grading, a qualified geotechnical consultant should be employed for the
purpose of observing earthwork procedures and testing the fills for conformance with the
recommendations of the geotechnical report and these specifications. It shall be the responsibility
of the contractor to assist the consultant and keep him apprised of work schedules and changes, at
least 24 hours in advance, so that he may schedule his personnel accordingly. No grading
operations should be performed without the knowledge of the geotechnical consultant. The
contractor shall not assume that the geotechnical consultant is aware of all grading operations.
It shall be the sole responsibility of the contractor to provide adequate equipment and methods to
accomplish the work in accordance with the applicable grading codes and agency ordinances,
recommendations in the geotechnical report and the approved grading plans not withstanding the
testing and observation of the geotechnical consultant If, in the opinion of the consultant,
unsatisfactory conditions, such as unsuitable soil, poor moisture condition, inadequate compaction,
adverse weather, etc., are resulting in a quality of work less than recommended in the geotechnical
report and the specifications, the consultant will be empowered to reject the work and recommend
that construction be stopped until the conditions are rectified.
Maximum dry density tests used to evaluate the degree of compaction shouls be performed in
general accordance with the latest version of the American Society for Testing and Materials test
method ASTM D1557.
3.0 Preparations of Areas to be Filled
3.1 Clearing and Grubbing: Sufficient brush, vegetation, roots and all other deleterious material
should be removed or properly disposed of in a method acceptable to the owner, design
engineer, governing agencies and the geotechnical consultant.
The geotechnical consultant should evaluate the extent of these removals depending
on specific site conditions. In general, no more than 1 percent (by volume) of the fill material
should consist of these materials and nesting of these materials should not be allowed.
3.2 Processing: The existing ground which has been evaluated by the geotechnical consultant
to be satisfactory for support of fill, should be scarified to a minimum depth of 6 inches.
Existing ground which is not satisfactory should be overexcavated as specified in the
following section. Scarification should continue until the soils are broken down and free of
large clay lumps or clods and until the working surface is reasonably uniform, flat, and free
of uneven features which would inhibit uniform compaction.
3.3 Overexcavation: Soft, dry, organic-rich, spongy, highly fractured, or otherwise unsuitable
ground, extending to such a depth that surface processing cannot adequately improve the
condition, should be overexcavated down to competent ground, as evaluated by the
geotechnical consultant. For purposes of determining quantities of materials overexcavated,
a licensed land surveyor / civil engineer should be utilized.
3.4 Moisture Conditioning: Overexcavated and processed soils should be watered, dried back,
blended and / or mixed, as necessary to attain a uniform moisture content near optimum.
3.5 Recompaction: Overexcavated and processed soils which have been properly mixed,
screened of deleterious material and moisture-conditioned should be recompacted to a
minimum relative compaction of 90 percent or as otherwise recommended by the
geotechnical consultant.
3.6 Benching: Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal
to vertical), the ground should be stepped or benched. The lowest bench should be a
minimum of 15 feet wide, at least 2 feet into competent material as evaluated by the
geotechnical consultant. Other benches should be excavated into competent material as
evaluated by the geotechnical consultant. Ground sloping flatter than 5:1 should be benched
or otherwise overexcavated when recommended by the geotechnical consultant.
3.7 Evaluation of Fill Areas: All areas to receive fill, including processed areas, removal areas
and toe-of-fill benches, should be evaluated by the geotechnical consultant prior to fill
placement.
4.0 Fill Material
4.1 General: Material to be placed as fill should be sufficiently free of organic matter and other
deleterious substances, and should be evaluated by the geotechnical consultant prior to
placement. Soils of poor gradation, expansion, or strength characteristics should be placed
as recommended by the geotechnical consultant or mixed with other soils to achieve
satisfactory fill material.
4.2 Oversize: Oversize material, defined as rock or other irreducible material with a maximum
dimension of greater than 6 inches, should not be buried or placed in fills, unless the
location, materials and disposal methods are specifically recommended by the geotechnical
consultant. Oversize disposal operations should be such that nesting of oversize material
does not occur, and such that the oversize material is completely surrounded by compacted
or densified fill. Oversize material should not be placed within 10 feet vertically of finish
grade, within 2 feet of future utilities or underground construction, or within 15 feet
horizontally of slope faces, in accordance with the attached detail.
4.3 Import: If importing of fill material is required for grading, the import material should meet
the requirements of Section 4.1. Sufficient time should be given to allow the geotechnical
consultant to observe (and test, if necessary) the proposed import materials.
5.0 Fill Placement and Compaction
5.1 Fill Lifts: Fill material should be placed in areas prepared and previously evaluated to
receive fill, in near-horizontal layers approximately 6 inches in compacted thickness. Each
layer should be spread evenly and thoroughly mixed to attain uniformity of material and
moisture throughout.
5.2 Moisture Conditioning: Fill soils should be watered, dried-back, blended and/or mixed, as
necessary to attain a uniform moisture content near optimum.
5.3 Compaction of Fill: After each layer has been evenly spread, moisture-conditioned and
mixed, it should be uniformly compacted to no less than 90 percent of maximum dry density
(unless otherwise specified). Compaction equipment should be adequately sized and be
either specifically designed for soil compaction or of proven reliability, to efficiently achieve
the specified degree and uniformity of compaction.
5.4 Fill Slopes: Compacting of slopes should be accomplished in addition to normal
compacting procedures, by backrolling of slopes with sheepsfoot rollers at increments of 3
to 4 feet in fill elevation gain, or by other methods producing satisfactory results. At the
completion of grading, the relative compaction of fill out to the slope face would be at least
90 percent.
5.5 Compaction Testing: Field tests of the moisture content and degree of compaction of the
fill soils should be performed at the consultant’s discretion based on file dconditions
encountered. In general, the tests should be taken at approximate intervals of 2 feet in
vertical rise and/or 1,000 cubic yards of compacted fill soils. In addition to, on slope faces,
as a guideline approximately one test should be taken for every 5,000 square feet of slope
face and /or each 10 feet of vertical height of slope.
6.0 Subdrain Installation
Subdrain systems, if recommended, should be installed in areas previously evaluated for suitability
by the geotechnical consultant, to conform to the approximate alignment and details shown on the
plans or herein. The subdrain location or materials should not be changed or modified unless
recommended by the geotechnical consultant. The consultant however, may recommend changes
in subdrain line or grade depending on conditions encountered. All subdrains should be surveyed
by a licensed land surveyor / civil engineer for line and grade after installation. Sufficient time shall
be allowed for the survey, prior to commencement of filling over the subdrains.
7.0 Excavation
Excavations and cut slopes should be evaluated by a representative of the geotechnical consultant
(as necessary) during grading. If directed by the geotechnical consultant, further excavation,
overexcavation and refilling of cut areas and/or remedial grading of cut slopes (i.e. stability fills or
slope buttresses) may be recommended.
8.0 Quantity Determination
For purposes of determining quantities of materials excavated during grading and/or determining
the limits of overexcavation, a licensed land surveyor / civil engineer should be utilized.
SIDE HILL STABILITY FILL DETAIL
FINISHED SLOPE FACE
PROJECT 1 TO 1 LINE
FROM TOP OF SLOPE TO
OUTSIDE EDGE OF I< EY
OVERBURDEN OR
UNSUITABLE
MATERIAL
EXISTING GROUND --
SURFACE~ --------
,,,...---.,,,,,.
/ ,.,,.,... / .,,...,,..
/ .,,...,,..
/ --,.,,.,... / ..,,,--
,,,,,., ✓ / / FINISHED CUT PAO
/ /
-------MP_A_CTeo-:-=
_-:f:f:§:j:j f !J....L_p::--
~ ·-----------
I
--
-
----------------------PAO OVEREXCAVATION DEPTH
ANO RECOMPACTION MAY BE
RECOMMENDED BY THE
GEOTECHNICAL CONSUL TANT
BASED ON ACTUAL FIELD
CONOIT-IONS-.ENCOUNTERED.
(
COMPETENT BEDROCK OR
MATERIAL AS EVALU~TEO
BY THE GEOTECHNICAL
CONSULTANT
NOTE: Subdrain details and key width recommendations to be provided based
on exposed subsurface conditions
STABILITY FILL / BUTTRESS DETAIL
OUTLET PIPES
,4• ~ NONPERFORATEO PIPE,
100' MAX. O.C. HORIZONTALLY,
30' MAX. O.C. VERTICALLY
-~-=-~
KEY
DEPTH
--::COl,il'A-CI::J
--=---==~~~~==~~~:-~:~~::~=~~=.-.... -. ..----
2 ~\\I
MIN.
f
---------_21'-~~-====~~~~~-
ll~I I
KEY WIDTH j
AS NOTED ON .GRADING PLANS
15' MIN.
e• MIN.
31,4•-1-112·
CLEAN GRAVEL
(3ft~/ft. MIN.
... 9J
NON-PERFORAT
OVERLAP
PIP~::-==--:~~=!ijii~;;,,:Jj --FIL TEA FABRIC
ENVELOPE (MIRAFI
140N OR APPROVED
EQUIVALENT)*
.
see T-CONNECTION
DETAIL
4• ~
PERFORATED
PIPE
4• MIN.
BEDDING
SUBDRAIN TRENCH DETAIL
NOTES:
SEE SUBDRAIN TRENCH
DETAIL
LOWEST SUBDAAIN SHOULD
BE SITUATED AS LOW AS
POSSIBLE TO ALLOW
SUITABLE OUTLET
r-----,. 1 O' MIN.
PERFORATED I t · I EACH SIDE
PIPE~• CAP
NON-PER FORA
OUTLET PIP
T-CO.NNECTION DETAIL
* IF CAL TRANS CLASS 2 PERMEABLE
MATERIAL IS USED IN PLACE OF
314•-1-112• GRAVEL, FILTER FABRIC
MAY BE DELETED
SPECIFICATIONS FOR CALTRANS
CLASS 2 PERMEABLE MATERIAL
U.S. Standard
Sieve Size
l"
3/4"
3/8"
No. 4
No. 8
No. 30
No. SO
No. 200
% Passing
100
90-100
40-100
25-40
18-33
5-15
0-7
0-3
Sand Equiva1ent>7S
For buttress dimensions, see geotechnical report/plans. Actual dimensions of buttress and aubdrain
may be changed by the geotechnical consultant based on field conditions.
SUBDAAIN INSTALLATION-Subdraln pipe should be Installed with perforations down as depicted.
At locatlon, recommended by the geotechnical consultant, nonperforated pipe should be Installed
SUBORAIN TYPE-Subdraln type should be Acrylon trlle Butadlene Styrene (A.8.S.), Polyvinyl Chloride
(PVC) or approved equivalent. Class 125,SDR 32.5 should be used for maximum fill depths of 35 feet.
Claaa 200, SOR 21 1hould be used for maximum fill depth• of 100 feet.
KEY AND BENCHING DETAILS
FILL SLOPE ~':.~~~~~ 6~ ~L~:: \\\~~!!!
TO COMPl!TENT MATERI ~:;!.l.~~~::-
EXIST1NG
GROUND SURFAC
2' MIN.L15' MIN~ KEY ILOWEST--7
0EPTH BENCH
(KEY)
BENCH
ACTE0=-:~
FILL-OVER-CUT SLOPE ILL~-----=-
EXISTING ~
GROUND SURF ACE ) -
--------
--LO-WEST
...--MIN. BENCH
D~~fH (KEY)
CUT SLOPE
(TO BE EXCAVATEO
PRIOR TO FILL
PLACEMENT) //~
CUT-OVER-FILL SLOPE
PROJECT 1 TO 1
LINE FROM TOE
OF SLOPE TO
COMPETENT
MATERIAL
EXISTING / /
GROUND / /
SURFACE~// K
// ~l~.?' / I,, 1.,, .....
/
-::,JI
CUT SLOPE
(TO BE EXCAVATED
PRIOR TO FILL
PLACEMENT)
NOTE: Back drain may be recommended by the geotechnical consultant based on
actual field conditions encountered. Bench dimension recommendations may
also be altered based on field conditions encountered.
ROCK DISPOSAL DETAIL
PIN&aH GRADE
GRANULAR SOIL (S.E.~ 30) TO BE 0ENSIFIED IN PLACE BY FLOODING _ _;;:,,,.-c:::::..._ ___ __ DETAIL
--------------------------------------------
--------------------------------------------
TYPICAL PROFILE ALONG WINDROW
1) Rock with maximum dimensions greater than 6 inches should not be used within 10 feet vertically of finish grade (or 2 feet below depth of lowest utility whichever is greater), and 15 feet horizontally of slope faces.
2) Rocks with maximum dimensions greater than 4 feet should not be utilized in fills.
3) Rock placement, flooding of granular soil, and fill placement should be observed by the geotechnical consultant.
4) Maximum size and spacing of windrows should be in accordance with the above details Width of windrow should not exceed 4 feet. Windrows should be staggered vertically (as depicted).
5) Rock should be placed in excavated trenches. Granular soil (S.E. greater than or equal to 30) should be flooded in the windrow to completely fill voids around and beneath rocks.
APPENDIX C
Poff Residence – Proposed ADU
4374 Tuolumne Place, Carlsbad, California Job No. 226735-1
ENGINEERING DESIGN GROUP
GEOTECHNICAL, CIVIL, STRUCTURAL CONSULTANTS
LABORATORY RESULTS
Method Cal-Trans
Analyte Result Reporting
Limit Units Dilution Method
SULFATE 45.2 n/a ppm 1 CT 417
CHLORIDE 5.5 n/a ppm 1 CT 422
p.H. 8.49 n/a pH units 1 CT 643
RESISTIVITY 6050 n/a ohms.com 1 CT 643
ND=None detected – us/cm = micro-Siemens per centimeter - ppm-parts per million
(10,000ppm=1% by weight)
ENGINEERING
DESIGN GROUP
www.designgroupca.com
2121 Montiel Road, San Marcos, CA 92069
760.839.7302
APPENDIX D
llll ENGINEERING DESIGN GROUP
2121 MONTIEL ROAD PHONE: {760) 839-7302
SAN MARCOS, CALIFORNIA 92069 FAX: {760) 480-74n
CONC OR CMU----,__,.'----+-....,,__
RET WALL FER
FLAN l DETAILS
I-IYOROTITE WATER-
STOFS AT COLO-
JOINTS FER f"FR
INSTALLATION
INSTFi!LICTIONS
SL.Al3 l VAPOR
1!3ARRIER FER
FLAN l
DETAILS
MINIMUM WATEREfsQOFING
SPECIFICATIONS (NOT TO SCALE)
r.i\ FOAM UV PROTECTION BOARD FER \.V MANI.FACTURER'S SPECIFICATION
GRACE FROCOR FLUID-APPLIED
WATERFROCf=ING INSTALLED FER
MANI.FACTURER'S SPECIFICATIONS
l EXTEND E3EI-IINO CEMENTITOUS
BACl<ER BOARD.
f"i\ GRACE I-IYOROOUCT 22,J 0 INSTALLED FER MANI.FACTURER'S
SFECIFICA TIONS OYER
FLUID-APPLIED WA TERFROCf=ING (l) TEFNINATION f3AR FER
MANLFACTURER'S
SFECIFICA TIONS
FILTER FAl3RIC WI 6" MIN LAP
314" GRA\iEL (I SF I FT)
4" DIA t=EFiFORATED DRAIN LINE (SCI-I 4,; OR
EQJIVJ t=EFiFORATIONS ORIENTED DOILN IS
MINIMUM GRADIENT TO SUITABLE OUTLET -
EXACT PIPE LOCATION TO E3E OETEFiHINED er SITE CONSTRAINTS
® 4" TALL CONCRETE CANT • FTG I WALL
CONNECTION (IK)ER WATERFROCf=INGJ.
SLOPE TO 13ACI<. EDGE C1= FOOTING.
® ca-tPACTEO l3ACl<FILL ~ MIN RELATl\iE
ca-tPACTION IN ALL OTI-IER AREAS U.O.N.
6 11 MAX LIFTS. ONLY LIGI-ITUEIGI-IT
I-IANO-OFERA TED EQJIFMENT SI-IALL E3E USED
WITI-IIN 3 FEET C1= Tl-IE 13ACI<. FACE C1= WALL.
EDG Project No. 226735-1
Date: November 10th, 2022
To: Ms. Nichole Fine
City of Carlsbad
Land Development Engineering
1635 Faraday Avenue
Carlsbad, California 92008
Re: Proposed accessory dwelling unit to be located at 4374 Tuolumne Place, Carlsbad,
California
Subject: Addendum No. 1 – Updated Recommendations and Response to Comments.
EDG Project: 226735-1
Project ID: PD2022-0012
Grading No. GR2022-0018
References:
1. “Preliminary Geotechnical Investigation and Recommendations Proposed, New Accessory
Dwelling Unit to be located at 4374 Tuolumne Place, Carlsbad, California”, prepared by
Engineering Design Group, dated April 5, 2022.
2. Geotechnical Report Review, Poff Residence, 4374 Tuolumne Place (1st Review), From City of
Carlsbad – Land Development Engineering, dated August 18, 2022.
3. bHA, Inc., Grading Plans for: Poff ADU.
1.0 PURPOSE
We have prepared this addendum to provide updated recommendations to the above referenced
preliminary geotechnical report (Reference No. 1) based upon the updated preliminary grading plans
(Reference No. 3), for the proposed accessory dwelling unit to be located at 4374 Tuolumne Place, in the
City of Carlsbad. This addendum will also address City of Carlsbad – Land Development Engineering
Department’s – Geotechnical Report Review comments (Reference No. 2). The response to comments
will be incorporated into this Addendum.
ENGINEERING
DESIGN GROUP
www.designgroupca.com
2121 Montiel Road, San Marcos, CA 92069
760.839.7302
EDG Project No. 226735-1
2.0 SITE
As described in our original report, the subject lot consists of a previously graded building pad located at
the western portion of the lot. The building pad is flanked to the east by a descending, graded slope to
the street below. The proposed accessory dwelling unit is to be located at the southeastern portion of the
lot, an area that is generally undeveloped and gently sloping. Based upon our review of available City
documents (Tract 84-35 Falcon Hills Plans by Snipes-Dye Associates, as referenced in our original report)
as part of the preparation of our original report (Reference No.1), we understand the lot was graded as
part of the creation of a tract subdivision. Based upon the original, reviewed plans, we understand grading
operations for this lot included a new, descending, graded slope at the eastern portion of the building
pad. It appears, the graded slope included deeper fills at portions closer to the building pad (western
portion of slope), and cuts at areas closer to the toe (eastern portions of slope); the fills were placed at a
gradient of 3:1. This research also indicates the graded fills are underlain by Santiago Formation. Based
upon review of site topography, the elevation differential of the existing slope is approximately 26 feet,
from existing house pad elevation to toe of slope at street.
3.0 GEOLOGY AND FAULTS
The project site is located within the Peninsular Ranges Geomorphic Province of California. The Peninsular
Ranges extend 125 miles from the Transverse Ranges and the Los Angeles Basin south to the Mexican
Border and beyond. This Geomorphic province is bounded on the east by the Colorado Desert and the
Gulf of California. Topographically, this Province is composed of generally parallel ranges of steep-sloping
hills and mountains separated by alluvial valleys. More recent uplift and erosion has produced the
characteristic canyon and mesa topography existing today in the western portions of San Diego County,
as well as the deposition of surficial materials. The site area topography consists of coastal foothill terrain,
which includes mesas and relatively shallow drainages. The site is underlain by very old paralic deposits,
middle to early Pleistocene (as mapped per Kennedy, et.al., 2007). Old paralic deposits consist mainly of
poorly to moderately sorted beach and alluvial deposits comprised of interfingered siltstone, sandstone,
and conglomerate.
The nearest mapped active fault (Holocene) is the Rose Canyon Fault (Newport-Inglewood Fault zone) in
the Offshore Zone of Deformation, located approximately 20.5 miles southwest of the subject site. Other
major mapped faults in the region are the Elsinore Fault and associated faults within the Elsinore zone,
and the San Jacinto Fault and related branches within the San Jacinto zone. The subject site is
approximately 21 miles southwest from the Elsinore Fault zone and approximately 45 miles west from the
San Jacinto Fault zone.
Our review of geologic literature pertaining to the general site area indicates the subject site is not within
a mapped Alquist-Priolo fault zone. It is our opinion that the site could be subjected to moderate to severe
ground shaking in the event of a major earthquake along any of the faults in the Southern California
region. The seismic risk at this site is similar to that of the surrounding developed area.
EDG Project No. 226735-1
4.0 SLOPES AND TEMPORATY BACK-CUTS
Based upon our review of the grading plans, as part of proposed development for the construction of the
accessory dwelling unit, we anticipate a new cut-fill lot. New, permanent, relatively shallow
(approximately 2-3 feet), fill slopes are anticipated at eastern portions of pad. New fill slopes shall be
placed at a maximum 2:1 slope face ratio. In consideration of the relatively shallow depths to competent
material at easternmost portion of proposed pad where fill slopes will be located, and proposed depths
of new fill slopes, we anticipate keyway widths to be between 3 and 5 feet, to be confirmed in the field
during grading operations. As noted in our original report, subdrains shall be placed if groundwater
conditions are encountered during grading operations per our original recommendations and details. No
groundwater was encountered during our subsurface investigation and is generally not anticipated. No
permanent cut slopes are anticipated as part of proposed development.
Temporary back-cuts are anticipated at western, northern, and limited southern portions of pad for
proposed retaining wall construction. We do not anticipate vertical cuts as part of temporary back-cuts
for retaining wall construction. As noted in our original report, temporary cut slopes shall have a maximum
inclination of 1:1, (horizontal to vertical) at these western, northern, and limited southern locations.
Based upon our review of project grading plans, shallow temporary cuts are anticipated at southern
portion of the pad for retaining wall construction at this location. We anticipate and state the following:
• Retaining wall at this location is proposed directly adjacent to property line.
• Area adjacent to proposed accessory dwelling unit & south retaining wall, at neighboring
property to the south, has not been developed, and is generally undeveloped and at a similar
elevation as subject lot.
• A letter of permission from neighbor to the south, may be requested by project contractor for
temporary construction access, as needed and determined by project owner and/or contractor.
• Temporary back-cuts at 1:1 are anticipate as part of retaining wall construction.
All temporary back-cuts shall be excavated in accordance with OSHA requirements and OSHA Alternative
Sloping Plans and shall not undermine adjacent properties, public improvements, or any structures
without proper shoring of excavation and/or structures.
Based upon our review of the preliminary grading plans, we anticipate adjacent property and
improvements will not be negatively impacted from a geotechnical standpoint, provided the
recommendations of this report, generally accepted construction practices, applicable codes, OSHA
requirements, civil design elements are implemented and applicable city and/or county standards are
followed.
EDG Project No. 226735-1
5.0 SLOPE STABILITY ANALISYS
As part of the preparation of this addendum, a computer-generated slope stability analysis was performed
on the existing, graded, 3:1 slope at the eastern portion of the site. Slope stability calculations were run
utilizing Bishop’s Simplified Method. The soil strength parameters used in our analysis are presented
below. These conservative values are based on documented soil parameters, laboratory results, back-
calculations, our experience in this area, and our professional judgement.
Soil Type
Unit
Weight
(lbs/ft³)
Friction Angle
(Φ) (deg)
Cohesion
(psf)
Documented Fill (Qcf1) 120 32 50
Qvop12 – Very Old Paralic
Deposits2 120 32 200
Ts – Santiago Formation1 120 35 500
1 As noted in original subdivision documentation.
2 As mapped per Kennedy, et.al., 2007.
Slope stability calculations included static analysis and pseudo-static conditions of the existing slope.
These conditions were modeled along section B-B’ of the site. Based on our slope analysis, a global
minimum factor of safety of 1.5 for static conditions as well as the global minimum factor of safety of 1.1
for pseudo-static conditions along the portion of the slope was calculated.
Additionally, as part of the preparation of this Addendum, we conducted a limited shallow slope stability
analysis. Based upon our analysis it is our opinion that shallow slope failure (in the upper 2-3 feet) of
existing slopes on the order of up to 3:1 (horizontal to vertical) currently have a factor of safety greater
than 1.5 for shallow slope stability. Under conditions of uncontrolled drainage or concentrated runoff,
influenced by seasonal weathered factors, irrigation practices, vegetative slope coverage, and drainage
device management, shallow slope failure should be anticipated. Precautions and measures shall be taken
to avoid negative factors from influencing slope stability. Please see our Surface Drainage section of
original report for mitigative recommendations.
6.0 RETAINING WALLS
Retaining walls are anticipated as part of the proposed development of the accessory dwelling unit. Site
retaining walls of up to 5 feet, are anticipated at western, northern, and southern portions of building
pad. We anticipate new retaining wall foundations to extend through topsoil, weathered and unsuitable
materials, into competent paralic materials.
As described in our original report and in the Site section of this addendum, the accessory dwelling unit is
proposed at the toe of an existing slope. Based upon our review of Tract Subdivision documents (as
referenced in original report), our review of site topography and architectural plans, we understand that
EDG Project No. 226735-1
the existing, graded, fill slope was placed with a maximum 3:1 gradient (horizontal to vertical). A retaining
wall at the toe of the slope is proposed as part of proposed ADU construction.
Section 1808.7 .1 Building Clearance from Ascending Slopes provides prescriptive provisions for building
setback, from toe of slope, where implemented is assumed to provide protection from slope drainage,
erosion, and shallow failures. Section 1808.7.5 and section 1803.5.10 provides a mechanism to provide
alternative setback and clearance from the toe of an ascending slope when a geotechnical investigation
performed by a registered design professional is performed, and that the alternative prescribed toe of
slope setback is found consistent with the intent of section 1808.7 .1.
Specific to this point Engineering Design Group performed a geotechnical investigation of the subject
property and has determined that the proposed setback from toe of slope, specifically 4 feet, provides
protection relative to drainage, erosion, and shallow slope stability equivalent/consistent to that
contemplated in section 1808.7 .1. For specific information regarding this finding, refer to sections of the
original geotechnical report and this addendum, pertinent to drainage, erosion, and slope stability
7.0 SOIL TYPE AND VALUES
During our subsurface investigation, penetrometer readings were taken within our test pits. Readings
from our tests, indicate onsite soils posses an unconfined compressive strength of between 2.0 and 3.0
tons per square foot. Based upon onsite testing, observation of onsite soils and our experience, a
conservative value of 2,000 PSF for bearing capacity was provided in our original report.
Sulfate content and corrosivity testing were conducted as part of the preparation of our original report.
Additional laboratory testing of onsite samples was conducted as part of the preparation of this
addendum, which included expansion potential, shear strength, and proctor. Based upon laboratory
results, onsite soils possess a low expansion potential. Please see attachments for additional laboratory
results.
8.0 FOUNDATION SETTLEMENT
Where the recommendations of our original report and this addendum are followed, the maximum
expected total static settlement for the proposed structure supported on a conventional foundation
system utilizing a maximum allowable soil bearing pressure of 2,000 psf (deriving support in competent
re-compacted material), is estimated to be on the order of ½ to 1 inch. Differential settlement is not
expected to exceed ½ inch over a distance of twenty (20) feet.
9.0 CONSTRUCTION OBSERVATION AND TESTING
In addition to the recommendations provided in the original geotechnical report, concerning items that
require inspection/observation during construction operations, the following actions shall also be
included:
EDG Project No. 226735-1
• Observation of temporary excavations.
• Observation/mapping of geologic conditions during excavation operations.
• Inspection of proposed retaining wall back-drain systems.
All recommendations and design parameters from our original report, not discussed herein, remain
applicable. If you have any questions regarding this letter, please feel free to contact our office.
Sincerely,
ENGINEERING DESIGN GROUP
Steven Norris
GE 2590; CEG 2263
Attachments:
Figures:
Figure 4 – Geotechnical Map
Figure 5 – Section A-A’
Figure 6 – Section B-B’
Laboratory Results:
Expansion Index
Shear
Proctor
4374 TUOLUMNE PLACE
CARLSBAD, CALIFORNIA 92010
226735-1
10-5-2022 FIGURE NO.:
ENGINEERING
DESIGN GROUP
www.designgroupca.com
GEOLOGIC I GEOTECHNICAL MAP
POFF RESIDENCE -PROPOSED ADU
EXISTING, GRADED,
J:1 SLOPE
J.,OT160
MAPlJ612
E)(JST, S1.()Pf
(J;I) \
I , '''
GEOLOGIC/GEOTECHNICAL MAP
'
J_o _______ or--___ ___::Jo
-• -I 1W •
2121 Montiel Road, San Marcos, CA 92069
760.839.7302
SCALE 1• = JO FT
60 90
I I
LEGEND
@;] ( )
IQvoP,21
IT!]
T2 ()
.,,,,-...._✓
----
Al jA
JOB NAME:
JOB ADDRESS:
JOB NO.:
DATE:
Topsoil and Certified Fill (buried units
shown in parentheses)
Very Old Paralic Deposits (As Mapped per
Kennedy, et.al. 2007)
Santiago Formation (As mapped in subdivision
documentation -referenced in original report)
Exploratory Test Pit -Per Original Report
Geologic Contact (In section view)
Approximate Property
Line Boundary
Section
Approximate Limits of
Proposed Improvements
Approximate Limits of
New, Graded, RI/ Slopes
(Cross Hatch)
Approximate Limits of
Remedial Grading
(Section View)
Approximate Limits of
Retaining Wall Backfill
(Section View)
POFF RESIDENCE -PROPOSED ADU
4
4374 TUOLUMNE PLACE
CARLSBAD, CALIFORNIA 92010
226735-1
10-5-2022 FIGURE NO.:
360.0
350.0
340.0
330.0
320.0
XISTING 3: 1 SLOPE
TO REMAIN
·---......
...... ...... ? .......
...... ......
............ ? .......
...... ...... ......
(2 PRE-GRADED, EXISTING SLOPE AND PAD, AT
WESTERN PORTIONS OF PROPOSED ADU LOCATION,
NOT INVESTIGATED -NOT PART OF SCOPE).
AREA OF BACKFILL
(EARTHEN HATCH)
............ ?. ....... ...... ...._
1: 1 TEMPORARY
BACK-CUT
~3•
PROPOSE
STRUCTURE
AREA OF REMEDIAL GRADIN
DIAGONAL HATCH
PROPOSE
GRADE
Qvop,23
ROPOSED STRUCTURE
BEYOND SECTION
ROPOSED
GRADED FILL
SLOPE
PPROXIMATE AND
PROJECTED LOCATION
OF TEST PITS (TYP.)
315.0 J-L-------+----------------+----------------+----------------+--------------+--------------+----------------+-
0+00.00 0+25.00 0+50.00
1APPROXIMATE AND PROJECTED LOCATION OF TEST PITS IN SECTION VIEW
2AS DESCRIBED IN ORIGINAL GEOLOGIC MAP ASSOCIATED WITH GRADING PLANS
FOR CARLSBAD TRACT 84-35 FALCON HILLS (FOR REFERENCE PLEASE SEE APPENDIX A OF ORIGINAL REPORT)
3AS DESCRIBED PER KENNEDY, ET.AL., 2008.
ENGINEERING
DESIGN GROUP
www.designgroupca.com
2121 Montiel Road, San Marcos, CA 92069
760.839.7302
0+75.00
SECTION A -A'
SCALE: 1 "= 10 '-0"
1 +00.00
JOB NAME:
JOB ADDRESS:
JOB NO.:
DATE:
1 +25.00 1+50.
POFF RESIDENCE -PROPOSED ADU
5
4374 TUOLUMNE PLACE
CARLSBAD, CALIFORNIA 92010
226735-1
10-5-2022 FIGURE NO.:
XISTING RESIDENCE
0+00.00 370.0 PL
BEYOND SECTION (DASHED)
I
360.0
350.0
340.0
330.0
320.0
315.0
0+00.00 0+25.00 0+50.00 0+75.00
1APPROXIMATE AND PROJECTED LOCATION OF TEST PITS IN SECTION VIEW
2AS DESCRIBED IN ORIGINAL GEOLOGIC MAP ASSOCIATED WITH GRADING PLANS
-
1+00.00 1 +25.00
SECTION B -B'
SCALE 1" = 20'
FOR CARLSBAD TRACT 84-35 FALCON HILLS (FOR REFERENCE PLEASE SEE APPENDIX A OF ORIGINAL REPORT)
ENGINEERING
DESIGN GROUP
www.designgroupca.com
2121 Montiel Road, San Marcos, CA 92069
760.839.7302
1 +50.00 1+75.00
2+40.00
ROPOSED ADU
(DASHED: PORTION
OF STRUCTURE AT
FOREGROUND OF
SECTION)
---1--+--:::~ ROPOSED
2+00.00 2+25.00 2+40.00
'APPROX. CUT/FILL CONTACT
PER ORIGINAL GRADING PLAN
GRADE -NEW,
GRADED, FILL
SLOPE
JOB NAME: POFF RESIDENCE -PROPOSED ADU
JOB ADDRESS:
JOB NO.: 6 DATE:
10-3988L Lab Number:33896
Client Date Sampled:9/21/2022
D.V.Date Tested:10/10/2022
LAB WORK SHEET EXPANSION INDEX TEST
Initial Final
WET WEIGHT (g)214.8 423.0
DRY WEIGHT (g)194.3 348.8
% MOISTURE (%)10.6 21.3
WEIGHT OF RING & SOIL (g)751.1
WEIGHT OF RING (g)365.3
WEIGHT OF SOIL (lbs.)0.8505
VOLUME OF RING (ft.3)0.0073
WET DENSITY (pcf)117.0
DRY DENSITY (pcf)105.8
% SATURATION (%)48.4
EXPANSION READING
DATE TIME: INITIAL READING INCH
0.0531 VERY LOW 0-20
LOW 21-50
MEDIUM 51 -90
FINAL READING HIGH 91-130
0.0795 VERY HIGH 130>
EXPANSION INDEX
26
NOTES: Equipment ID: 2C
EI at saturation between 48-52%
Measured EI:26.4
Measured Saturation:48.4
EI at 48-52% Saturation:26
ASTM D 4829
TEST RESULTS
Soil Description:Light Brown (SC)
Job Name:EDG (POFF)
Job Number:
Sampled By:
Tested By:
Soil Location:Poff
A Universal
Engineering
Sciences
Company
i i
SHEAR STRENGTH TEST - ASTM D3080
Job Name:
Project Number:10-3988L
Lab Number:33896
Sample Location:Tested By:
Sample Description:
L.S.
10/11/2022
Angle Of Friction:33.9
Cohesion:
E.D.G. ( Poff)
270 psf
Initial Dry Density (pcf):117.4
Initial Moisture (%):12.7
Final Moisture (%):22.9
Poff
Sample Date:
Test Date:
9/26/2022
Light Brown (SC) Remolded to 90%
0
0.5
1
1.5
2
2.5
30.1 1 10 100
ST
R
A
I
N
(
i
n
c
h
e
s
)
TIME (minutes)
PRECONSOLIDATION
0
1000
2000
3000
4000
5000
0 2 4 6 8 10 12 14 16 18 20
SH
E
A
R
S
T
R
E
S
S
(
p
s
f
)
STRAIN (%)
SHEARING DATA
0
1000
2000
3000
4000
5000
0 1000 2000 3000 4000 5000
SH
E
A
R
I
N
G
S
T
R
E
S
S
(
p
s
f
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VERTICAL STRESS (psf)
FAILURE ENVELOPE
dr=0.08 mm./min
VERTICAL STRESS
1000 psf
3000 psf
5000 psf
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J.G.Date:
J.G.Date:
E.D.G.Date:
N/A
Sample Description:
150 200 100 250
1 2 3 4 Dry X
4027 4000 3927 3931 Moist
2025 2025 2025 2025
2002 1975 1902 1906 X
217.5 211.5 213.0 212.0
192.5 184.0 192.0 181.0
0.0 0.0 0.0 0.0
Drop:
13.0 14.9 10.9 17.1
132.5 130.8 125.9 126.2
117.3 113.8 113.5 107.7
Procedure A
Soil Passing No. 4 (4.75 mm) Sieve
Mold : 4 in. (101.6 mm) diameter
Layers : 5 (Five)
Blows per layer : 25 (twenty-five)
May be used if No.4 retained =/< 25%
X Procedure B
Soil Passing 3/8 in. (9.5 mm) Sieve
Mold : 4 in. (101.6 mm) diameter
Layers : 5 (Five)
Blows per layer : 25 (twenty-five)
May be used if 3/8" retained =/< 25%
Procedure C
Soil Passing 3/4 in. (19.0 mm) Sieve
Mold : 6 in. (152.4 mm) diameter
Layers : 5 (Five)
Blows per layer : 56 (fifty-six)
May be used if 3/4" retained =/< 30%
Plus 3/4"
Plus 3/8"
Plus #4 N/A
2.2
Sample Location:Poff
10.0 lb.
Wet Wt. of Soil + Cont. (g)
Dry Wt. of Soil + Cont. (g)
Mechanical Rammer
Manual Rammer
OVERSIZE FRACTION
Total Sample Weight (g):15245
Percent RetainedWeight Retained (g)
N/A
9/21/2022
Wt. of Container (g)
Depth (ft.)
TEST NO.
Wt. Comp. Soil + Mold (g)
Hammer Weight:
Net Wt. of Soil (g)
33896Lab Number:
Moisture Added (ml)
9/26/2022
9/26/2022
Wt. of Mold (g)
Light Brown (SC)
Preparation Method:
Tested By :
Calculated By:
Sampled By:
Project Name:
Project Number:
Optimum Moisture Content (%)
342
10-3988L
18 in.
Dry Density (pcf)
Moisture Content (%)
Wet Density (pcf)Mold Volume (ft.3):0.03330
LABORATORY COMPACTION OF SOIL (MOD.)
ASTM D 1557
Rock Correction Applied per ASTM D 4718
Maximum Dry Density (pcf)
Optimum Moisture Content (%)
Maximum Dry Density (pcf)
PROCEDURE USED
117.4
12.7
EDG (Poff)
105.0
110.0
115.0
120.0
125.0
0.0 5.0 10.0 15.0 20.0
Dr
y
D
e
n
s
i
t
y
(
p
c
f
)
Moisture Content (%)
SP. GR. = 2.65
SP. GR. = 2.70
SP. GR. = 2.75
33896 - Proctor
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\ •
EDG Project No. 226735-1
Date: July 7th, 2023
To: Ms. Nichole Fine
City of Carlsbad
Land Development Engineering
1635 Faraday Avenue
Carlsbad, California 92008
Re: Proposed accessory dwelling unit to be located at 4374 Tuolumne Place, Carlsbad,
California
Subject: Addendum No. 2 – Response to Comments, Import Cap, and Updated Recommendations
EDG Project: 226735-1
Project ID: PD2022-0012
Grading No. GR2022-0018
References:
1. “Preliminary Geotechnical Investigation and Recommendations Proposed, New Accessory
Dwelling Unit to be located at 4374 Tuolumne Place, Carlsbad, California”, prepared by
Engineering Design Group, dated April 5, 2022.
2. Addendum No. 1 – Updated Recommendations and Response to Comments, prepared by
Engineering Design Group, dated November 10th, 2022.
3. Geotechnical Report Review, Poff Residence, 4374 Tuolumne Place (2nd Review), From City of
Carlsbad – Land Development Engineering, dated March 25, 2023.
4. bHA, Inc., Grading Plans for: Poff ADU, received July 20, 2023.
We have prepared this addendum to our geotechnical report and addendum no. 1 (References No. 1 and
No. 2, respectively) to provide updated recommendations and to address City of Carlsbad – Land
Development Engineering Department’s – Geotechnical Report Review comments (Reference No. 3) for
the proposed accessory dwelling unit to be located at 4374 Tuolumne Place, in the City of Carlsbad
(Reference No. 4). The response to comments will be incorporated into this Addendum.
ENGINEERING
DESIGN GROUP
www.designgroupca.com
2121 Montiel Road, San Marcos, CA 92069
760.839.7302
EDG Project No. 226735-1
1.0 COMMENT: BUTTRESS FILL AND SUBDRAIN
Based upon our review of available City documents (Tract 84-35 Falcon Hills Plans by Snipes-Dye
Associates, as referenced in our original report) as part of the preparation of our original report (Reference
No.1), we understand the lot was graded as part of the creation of a tract subdivision. Based upon the
original, reviewed plans, buttress fill material encroaches the subject property at a limited location at the
south-central portion of the lot. Additionally, a buttress sub-drain is indicated on the original grading
plans, at adjacent lots. Original recommendation referenced on City comment 1 is precautionary, in the
unlikely event subdivision subdrain extends to subject property. In our experience, mass grading plans,
associated with older subdivisions may have slight discrepancies with actual site conditions, specifically,
sub-drain/subterranean improvements. Please see revised Figure 4, attached herein; subdivision grading
plan buttress fill, and associated sub-drain locations have been added.
2.0 COMMENT: FAULTING
The nearest mapped active fault (Holocene) is the Rose Canyon Fault (Newport-Inglewood Fault zone) in
the Offshore Zone of Deformation, located approximately 4.5 miles west of the subject site. Other major
mapped faults in the region are the Elsinore Fault and associated faults within the Elsinore zone, and the
San Jacinto Fault and related branches within the San Jacinto zone. The subject site is approximately 21
miles southwest from the Elsinore Fault zone and approximately 45 miles west from the San Jacinto Fault
zone.
The Rose Canyon Fault has been determined to be capable of producing earthquakes of magnitude 6.9.
The Elsinore Fault and associated faults have been determined to be capable of producing earthquakes of
magnitudes 6.5-7.5 Mw. The San Jacinto Fault and its associated faults have been determined capable to
produce earthquakes of magnitudes 6.5-7.5 Mw.
3.0 COMMENTS: GEOLOGIC STRUCTURE AND SUBSURFACE CONDITIONS
The project area is situated in the Peninsular Ranges Geomorphic Province. The province is characterized
by mountainous terrain on the east composed mostly of Mesozoic igneous and metamorphic rocks, and
relatively low-lying coastal terraces to the west underlain by Tertiary-age, and Quaternary-age
sedimentary units. Most of the coastal region of San Diego County occurs on these coastal terraces and is
underlain by sedimentary units. More specifically, the project site is located within the coastal plane
portion of the Peninsular Ranges Geomorphic Province. Geologic units underlying the project site consist
of localized, relatively shallow, weathered topsoil, and certified fill profiles, overlying Very Old Paralic
Deposits and formational materials beyond. Certified fill and/or paralic deposits were encountered in our
original subsurface investigation (Reference No. 1). The paralic deposits encountered, underlying the
shallow, weathered profiles and certified fill, consisted of reddish brown to light brown to light gray, silty
sands with regions of interbedded, poorly graded, silty sand and sandy silt mixtures. Based upon our
review of geologic maps, topographic maps, grading plans, and our subsurface investigation, the paralic
deposits strike in a north-west direction, with an eastern direction of dip. Based upon our review of
EDG Project No. 226735-1
geologic literature pertaining to the site, no fractures or faulting are mapped in the vicinity of the project
site.
We anticipate the structural geology of the soil profiles underlying the site, will not have a negative impact
on proposed construction and improvements. The mapped soil profiles underlying the site, generally have
favorable geologic structure, with nominal or low risk for geologic hazards. Additionally, the specific
portion of the lot where the ADU and improvements, are proposed, is generally flat to gently sloping.
Based upon our review of various geologic maps by Kennedy, et.al., and City of Carlsbad Records (Grading
Plan for: Carlsbad Tract 84-35, Falcon Hills, dated 8-28-1985), we anticipate the overall site and adjacent
area to be underlain by formational material, mapped by others, as Santiago Formation. Our findings and
observations in the field, at the site and adjacent areas, were consistent with the review of geologic maps
and literature. At western portions of subject lot, where existing building pad and existing improvements
are located, and based upon review of aforementioned documents, we anticipate western portion of lot,
including building pad, and graded & certified slope to be composed of certified fill material underlain by
formation material. Eastern portion of subject lot was generally cut to grade, with localized fill areas, as
described in our original report. (Reference No. 1) and depicted on Figure No. 4. Although not
encountered during our initial field investigation (Reference No. 1), the Tertiary-aged Santiago Formation
is anticipated to underlie the paralic deposits at the site.
4.0 COMMENT: SLOPE STABILITY ANALYSIS
As part of the preparation of addendum no. 1, a computer-generated slope stability analysis was
performed on the existing, documented, graded, 3:1 slope at the eastern portion of the site. Slope stability
calculations were run utilizing Bishop’s Simplified Method. The soil strength parameters used in our
analysis are presented below. These conservative values are based on documented soil parameters,
laboratory results, back-calculations, our experience in this area, and our professional judgement.
Soil Type
Unit
Weight
(lbs/ft³)
Friction Angle
(Φ) (deg)
Cohesion
(psf)
Documented Fill (Qcf1) 120 32 50
Qvop12 – Very Old Paralic
Deposits2 120 32 200
Ts – Santiago Formation1 120 35 500
1 As noted in original subdivision documentation.
2 As mapped per Kennedy, et.al., 2007.
Printouts of our calculations for the above referenced slope stability analysis, done as part of addendum
no. 1, are attached herein. Please note, calculations were performed of section during most critical
scenario, temporary 1:1 back-cut and no retaining wall. Calculations from this temporary scenario,
indicate localized, surficial slope stability factors both for static and pseudo-static conditions, slightly
below accepted safety factors for these conditions, respectively. In consideration of the conservative
EDG Project No. 226735-1
parameters utilized in our calculations, and the elevated factors of safety for global slope stability during
permanent, proposed condition, we do not anticipate slope instability during or after construction
operations. As indicated in our original report and addendum No.1, all applicable codes, City, OSHA, and
construction practices are anticipated to be implemented.
5.0 COMMENT: SUBSURFACE CONDITIONS
Please see Section 3 above.
6.0 COMMENT: EXPANSION INDEX AND MITIGATIONS METHODS
Weathered materials that overlain the site were analyzed as part of our addendum no. 1. Laboratory
results indicate profiles tested, possess an expansion index of 26. Recommendations for slab-on-grade
floors presented in our original geotechnical report and in our Addendum No. 1, included the removal of
unsuitable onsite soils in areas of proposed slabs, and the placement and re-compaction of fill material as
part of grading operations for the creation of the ADU building pad.
In consideration of the expansion potential of soil profiles overlaying the site, we recommend the
placement of import material in the upper 24 inches of slab-on-grade subgrade. Import cap material shall
consist of soils with very low potential for expansion (E.I.<20). Foundations and slab-on-grade floors for
proposed ADU are anticipated to be placed in competent, re-compacted, low expansion, import cap
material.
It is our opinion that with our updated, ’24-inch import cap’ recommendation, the slab-on-grade floors
proposed, will meet the requirement of Section 1808.6 for the following reason: the removal of expansive
soil in areas below proposed slab-on-grade floors (Section 1808.6.3), and consequently the proposed
foundations and slab floors are to be founded on competent, low-expansion, import material.
The proposed foundation system and slab-on-grade floors for the ADU will meet the requirements of
Section 1808.6 of the 2019 California Building Code.
7.0 ADDITIONAL RECOMMENDATIONS – RETAINING WALLS
As described in our original report and addendum no. 1, we anticipate proposed site retaining walls at
western portion of site to be deepened through weathered materials, and founded in competent, paralic
material. Depths to competent materials at this western, retaining wall locations are anticipated to be 2.5
feet below existing grades. We anticipate all western retaining wall footing to be founded in uniform,
competent, paralic deposit materials. Area of removal and re-compaction (with import cap material, as
described above) shall be limited to building pad area.
Additionally, during retaining wall backfill operations, representative of Engineering Design Group shall
confirm suitability of onsite soils for retaining wall backfill. Import material may be required for retaining
wall backfill.
EDG Project No. 226735-1
Sincerely,
ENGINEERING DESIGN GROUP
Steven Norris
GE 2590; CEG 2263
Attachments:
Figures:
Figure 4 – Geotechnical Map - Updated
Slope Stability Printouts:
Section – Static
Section – Pseudo Static
4374 TUOLUMNE PLACE
CARLSBAD, CALIFORNIA 92010
226735-1
7-14-2023 FIGURE NO.:
ENGINEERING
DESIGN GROUP
www.designgroupca.com
GEOLOGIC I GEOTECHNICAL MAP
POFF RESIDENCE -PROPOSED ADU
GEOLOGIC/GEOTECHNICAL MAP ;
2121 Montiel Road, San Marcos, CA 92069
760.839.7302
30 0
~ ----30 60 90
I I I
SCALE 1• = JO FT
LEGEND
@;] ( )
T2 ()
A_I _jA
JOB NAME:
JOB ADDRESS:
JOB NO.:
DATE:
Topsoil and Certified Fill (buried units
shown in parentheses)
Very Old Paralic Deposits (As Mapped per
Kennedy, et.al. 2007)
Santiago Formation (As mapped in subdivision
documentation -referenced in original report)
Exploratory Test Pit -Per Original Report
Geologic Contact (In section view)
Approximate Property
Line Boundary
Section
Approximate Limits of
Proposed Improvements
Approximate Limits of
New, Graded, RII Slopes
(Cross Hatch)
Approximate Limits of
Remedial Grading
(Section View)
Approximate Limits of
Retaining Wall Backfill
(Section View)
POFF RESIDENCE -PROPOSED ADU
4
1.3201.320
2000.00 lbs/ft2
2000.00 lbs/ft2
1.3201.320
Tensile
Strength
(psf)
Ru
Value
Water
Surface
Phi
(°)
Cohesion
(psf)
Strength
Type
Unit
Weight
(lbs/ft3)
ColorMaterial
Name
0None3250Mohr-
Coulomb120Qcf
0None35500Mohr-
Coulomb120Ts
00None32200Mohr-
Coulomb120Qvop /
R&R
Safety Factor
0.000
0.500
1.000
1.500
2.000
2.500
3.000+
45
0
40
0
35
0
30
0
0 50 100 150 200 250 300
Scenario Master ScenarioGroupStatic
CompanyDrawn By
File Name POFF ADDENDUM.slmdDate10/13/2022, 11:18:21 AM
Project
SLIDE - An Interactive Slope Stability Program
SLIDEINTERPRET 9.028
□
□
□
LJ . rocsc 1ence >-------------->--------------------,1
1.0191.019 2000.00 lbs/ft2
2000.00 lbs/ft2
1.0191.019
0.15
Tensile
Strength
(psf)
Ru
Value
Water
Surface
Phi
(°)
Cohesion
(psf)
Strength
Type
Unit
Weight
(lbs/
ft3)
ColorMaterial
Name
0None3250Mohr-
Coulomb120Qcf
0None35500Mohr-
Coulomb120Ts
00None32200Mohr-
Coulomb120Qvop /
R&R
Safety Factor
0.000
0.500
1.000
1.500
2.000
2.500
3.000+
50
0
45
0
40
0
35
0
30
0
25
0
-100 -50 0 50 100 150 200 250 300 350
Scenario Master ScenarioGroupPseudo-Static
CompanyDrawn By
File Name POFF ADDENDUM.slmdDate10/13/2022, 11:18:21 AM
Project
SLIDE - An Interactive Slope Stability Program
SLIDEINTERPRET 9.028
□
□
□
LJ rocscience>------------------------------,1