HomeMy WebLinkAboutCT 75-02; CARLSBAD MEADOWS; SOIL AND GEOLOGIC INVESTIGATION; 1975-06-06• pplication for Grading Permit-
CITY OF CARLSBAD
PERMIT NO . ~---( I etter code + number) 1
L=lot
PUBLIC WORKS & BUILDING DEPARTMENT
1200 Elm Avenue
S=subdivision
C=City contract
729-118 I
FOR APPL! CANT TO FI LL IN
Site A1d ress En of Tamarack Avenue Surety Bond Bond No.
Leg a I Descr if ti on 5-2 Map No. Surety Company
Subdivision Name Surety Address Carlsbad Meadows Unit 41 1
Owner Phone Date Fi led Rec'd by
Sommers Development Corp. 756-3283
Owner's Address Cash deposit Rec'd by Date filed
P.O. Box 1754 Rancho Santa Fe, Calif 92067 $
PJans by Civi I Engineer R.C.E. The fol lowing documents are required and shal
Robert F, Young Engineering 8454 become a part of the grading permit when they
Address Phone are approved.
112 No. Orange Ave El Cajon, Calif 442-0594 __ Grading plans _Specifications
Soi I Engineer R.C. E. Phone _Soi I report _Vicinity map
Geocon Inc. 17030 292-5100 _Drainage structures __ Retaining wal Is
3rading Contractor Phone _Compaction report Other
Tempelton Grading 744-0630
~ddress Check if supervised SPECIAL CONDITIONS WHICH ARE MADE
1650 Linda Vista Rd San Marcofei rad i nq yes A PART OF THIS PERMIT
Party responsible for overal I supervision
Luis Orrantia I . Authorized hours of operation: 7:00 AM to
0 roposed use of grade site 5:00 PM, Monday-Friday.
,-A~ident-ial 2. Haul routes are to· be approved bv Citv
Number of cubic yards Engineer.
Cut Fi II Import Waste 3. Adeauate provisions shal I be made tor
erosion and siltation control.
55,800 I 53,000
I from unit 4121 4. All slopes shal I be Planted per direction
of Parks & Recreation Director. Total
55,800
El/l ,.J.." I • .. ~ .If IS''o/' ~II) Compacted ti I ls (yes or no) -II ·~ ~
yes V
Proposed Schedule of Start Finish
Operations (dates) August 16, 9/10/76
I hereby acknowledge that I have read the app Ii ca-
tion and state that the information I have prov i dee INSPECTION DATE INSPECTOR'S
is correct and agree to comply with all City SIGNATURE
ordinances an.d State laws regulating excavating anc Ground preparation
grading, and the provisions and conditions of any Rough grading permit issued pursuant to this application.
Compaction report rec'd. -·
Signature of Permittee , Planting & drainage ,
Owner or authorized agent~-==~-=-, ~
Final certification rec'd.
207.00 Work completed ' Grading permit fee$ '
Surety 0ond released
Pe€TJ\Va Ii d_,_ati o WA."''-}\.....:> Date 6At>/7e-_ by ~ r_,U,!J fJ • ',FI I V
Date· ~/t6/7C,
.
Permit Expiration
THIS FORM WHEN PROPERLY VALIDATED BY SIGNATURE IS A PERMIT TO DO THE WORK DESCRIBED
THIS PERMIT IS VALID FOR A SIX (6) MONTH PERIOD
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SOIL AND GEOLOGIC INVESTIGATION
for
CARLSBAD MEADOWS C'T7S·2'
Carlsbad, California
For:
SOMMERS DEVELOPMENT CORPORATION
Rancho Santa Fe, California
By:
GEOCON INCORPORATED
San Diego, California
JUNE 1975
RECEIVED
MAY 6 1976
CITY OF CARLSBAD
Engineering Department
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File No. D-0364-SOl
June 6, 1975
LETTER OF TRANSMITTAL
TABLE OF CONTENTS
SOIL AND GEOLOGIC INVESTIGATION
i
Purpose and Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Location and Description of Site and Project ........... ··~··· 1
Figure 1 -Site Plan ......................................... 3
Field Investigation .......................................... 4 Laboratory Investigation ..................................... 5
Soil and Geologic Conditions ................................. 5
Figure 2 -Trench Logs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 3 -Trench Logs & Section A-A' ........ ." ............... 8
CONCLUSIONS AND RECOMMENDATIONS
Gener a 1 ...................................................... 11
Slope Stability .............................................. 11
Figure 4 -Typical Buttress Fill Section ..................... 13
Grading ...................................................... 14
Foundations .................................................. 17
Slabs-on-Grade ............................................... 18
Drainage and Maintenance ..................................... 18
Gradin~ Plan Review .......................................... 19
LIMITATIONS AND UNIFORMITY OF CONDITIONS
APPENDIX A
20
Table 1 -In-Place Moisture-Density & Direct Shear ........... 23
Table 2 -Expansion Test Results ............................. 24
Figure 5 -Log of Test Boring No. 1. ......................... 25
Figure 6 -Log of Test Boring No. 1, Cont .................... 26
Figure 7 -Log of Test Boring No. 2 .......................... 27
Figure 8 -Log of Test Boring No. 3 .......................... 28
Figure 9 -Laboratory Consolidation Test ..................... 29
Figure 10-Laboratory Consolidation Test ..................... 30
Figure 11-Laboratory Compaction Test ........................ 31
APPENDIX B
Recommended Grading Specifications
General Description .......................................... 33
Tests ........... (I •••••••••••••••••••••••••••••••••••••••••••• 33
Clearing, Grubbing, and Preparing Areas to Be Filled ......... 33
Materials ... c ••••••••••••••• e .................... Cl •••••••••••• 35
Placing, Spreading, and Compacting Fill Material ............. 35
Supervision .... Cl ••••• ~ .......... ~ •••••••••••••••••••••••••••••• 36
Seasonal Limits .......... o ••••••••••••• " • " ........... c •••••••••• 36
ii GEOCON,
INCORPORATED
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File No. D-0364-S01
June 6, 1975
Just north of the extension of Tamarack Avenue and partly within I the limits of the site is a small earth fill dam and shallow reservoir I (see Figure 1). Existing fill slopes constructed during the grading
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of the subdivision west of the site are shown on Figure 1.
The stability of these fill slopes is discussed in the Conclusions
and Reconnnendations of this report.
Topographically, the site is situated on the ·western slope of a
wide, north-south trending canyon. The natural slopes approach
an inclination of two horizontal to one vertical which is considered
relatively steep. Numerous tributary gullies and channels have I developed on the primary slope. Drainage on the site is to the east
towards the center of the valley and then to the south following the
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existing ephemeral creek bottom.
Development of the site will consist of cutting the valley slopes and
filling the valley bottom to create pad areas for approximately 95
housing units. The maximum cut slope heights will be on the order
of 80 feet while fill slopes will be approximately 40 feet in maximum
height. The proposed slope ratios for cut and fill slopes are two
horizontal to one vertical. Conventional wood-frame construction is
proposed with concrete slab-on-grade floor systems.
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GEOCON
INCURPORATEII
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File No. D-0364-S01
June 6, 1975
Unit 1, consisting of Lots 1 through 44, will be graded first with
soils borrowed from Unit 2 (Lots 47 through 97). Lots 45, 46, 98,
and 99 are open space lots. The grading of Unit 2 ·will probably be
delayed until Unit 1 is completed and sales have begun.
Field Investigation
The field investigation was performed on May 23, 1975, and consisted
of a site inspection by our soil engineer and engineering geologist,
the drilling of three test borings to depths varying from 80 to 16
feet below the existing ground levels, and the excavation of four
exploratory trenches up to 230 feet in length. The drilling was
performed by a truck mounted caisson-type drilling with a 30 inch
diameter bucket. As drilling was advanced, undisturbed soil samples
were obtained by driving a three inch diameter split .spoon sampler
equipped with one inch high brass rings into the undisturbed soil
mass by dropping a 140 pound weight 30 inches. The samples obtained
were visually classified in accordance with the Unified Soil Classi-
fication System by the supervising soil engineer and then sealed
to be returned to the laboratory for testing. Disturbed bulk samples
were also obtained. The trenching was performed with a tractor-mounted
backhoe with a 24 inch wide bucket.
Figures 2 through 3 contain the logs of the exploratory trenches and
the geologic section A-A'. Figures 5 through 8, Appendix A, contain
the Log of Borings which depict the soil types encountered and the
location of samples.
GEOCON
INCORPORATED
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File No. D-0364-S01
June 6, 1975
formation overlies the Middle Eocene Torrey Sandstone and underlies
Member C and an early to middle Pleistocene unit correlated with the
Lindavista Formation of the southern San Diego County area.
Member Bon this project consists of relatively thick sequences of
thinly-bedded medium grained silty sandstone interbedded with silt-
stone and massively bedded claystones. The sandstone is generally
weakly cemented and has widely spaced, near vertical joints. The
claystone and siltstone is highly fractured and brittle near the
surface in trench exposures.
Bedding generally dips towards the west and northwest at angles from
two to 17 degrees. The notable exception to this westerly trend in
bedding attitude occurs in the area of Trench No. 1 wherein easterly
dips of up to 15 degrees were observed.
Boring 1 and Trenches 1 and 2 encountered a shear zone in claystone at
an elevation of approximately 150 feet. This zone is probably
continuous throughout the project at this elevation. Differential
movement between the sediments above and below the shear zone is
apparently responsible for its formation. A study of aerial photos
indicates that the observed shear zone is not a landslide related
phenomenon. The presence of this potential failure surface and
adversely dipping beds in the claystone could lead to future slope ··1
instabilities during the grading operation unless corrective measures
are taken (see conclusions and recom. for discussion of buttress fills).
-6-GEOCON
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File No. D-0364-S01
June 6, 1975
The residual soils on this site consist of very stiff, damp, black
to dark grey sandy clays with very high expansion potential. Slope-
wash soils occurring as result of erosion and soil creep on steep
slopes have accumulated in great depth near the base of slopes and
extend well out into the valley to the east. Slopewash soils, as
evidenced by the trenching and drilling operations consist of highly
expansive sandy .clays and clayey sands. Borings 2 and 3 penetrated a
thickness of over 15 feet of slopewash soils along the eastern limits
of the site. Very loose alluvial soils consisting of stream deposited
sands overlie portions of the project adjacent to Borings 2 and 3
and the existing drainage course. In general, the slopewash and
alluvial deposits are unconsolidated to a depth of approximately four
feet. These loose surficial soils shall be excavated and compacted
following the recommendations given in the Conclusions and Recommenda-
tions of this report. The small pond near the southeast corner of the
site wiJJ be drained. The loose alluvium, saturated soils, and uncom-
pacted fill in the dam that will underlie the proposed fill should also
be removed and recompacted prior to the placement of additional fill
soils .
There are no known active faults in this site or in the Carlsbad area.
The closest active fault is the Elsinore Fault which lies 35 to 40
miles to the northeast. The potentially active Rose Canyon Fault
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1'-CORPORATFI> _J
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File No. D-0364-SOl
June 6, 1975
may exist several miles off shore in the Carlsbad area. To date,
however, its presence this far north of the San Diego area is highly
speculative. The source of greatest seismic risk is the Elsinore
Fault which is capable of producing a Magnitude 7.3 earthquake during
the lifetime of the project. According to. the "Generalized Lithology
and Earthquake Damage Potential Map," prepared by the CPO for San
Diego County (Plate 1, 1972-1973), the property is in the middle of five
damage potential groups which range from greatest to least on the
basis of subsurface lithology. The earthgµake hazard for the site
is therefore not considered unusual for the southern California area.
No ground water was encountered during the investigation. If the
grading is done during the ~ainy season from December to April
(approximate) the water table, which will be higher during this
period, could cause grading problems during the removal and recompaction
of the unconsolidated alluvial and slopewash soils.
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GEOCON
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File No. D-0364-S01
June 6, 1975
CONCLUSIONS AND RECOMMENDATIONS
General
1. The site may be utilized for the proposed development provided the
recommendations of this report are carefully followed. The undis-
turbed native soils, properly compacted native soils or combinations
thereof should adequately support the proposed structures without
detrimental settlements.
2. The soil on the site varies in expansive potential from low (less
than 1.0 percent) to high (greater than 10 percent), It is unlikely
that sufficient quantities of low expansion soil will be present
on the site to cap all building pads and roadways. The bulk of the
low expansion material is at the upper elevations of. the highest cut
slopes. A selective grading operation should be utilized which
retains as much low expansion material as possible for capping or
for use in deeper fills.
3. Final foundation design recommendations will be presented upon
completion of grading operations. A range of anticipated reconnnendations
is contained in this report.
Slope Stability
4. The 2.0 horizontal to 1.0 vertical fill slopes which bound the
site on the west have been in place through one extremely wet rainy
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GEOCON
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File No. D-0364-S01
June 6, 1975
7. Geologic inspection of the placement and construction of all cut
and fill slopes will be required.
Grading
8. All grading should be performed in accordance with the Reconnnended
Grading Specifications contained in Appendix B.
9. Native soil excavated from colluvial or slopewash areas, or from
formational deposits, are suitable for use as compacted fill, if
free from organics or other deleterious material. All fill should
be placed at a minimum of 90 percent relative ca11P-action based upon
A.S.T.M. Compaction Test D1557-70, Method A.
10. All areas to be graded should be stripped of all grass, brush,
and other debris. The depth of stripping will depend upon weed
growth present at the time of grading. For estimating purposes, zero
to two inches may be assumed for the depth of stripping. Any
material stripped should not be used as compacted fill, but hauled
from the site or stockpiled for reuse as topsoil.
11. As discussed briefly elsewhere in this report, the site contains
deposits of loose unconsolidated soils that should be removed and
recompacted as described below:
a. Alluvium and Slopewash: Alluvial and slope-
wash soils have accumulated to great thicknesses
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GEOCON
INCURPORATEP
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File No. D-0364-S01
June 6, 1975
13. Fill, either from the aforemention overexcavations or from
on-site cutting operations, may then be placed in compacted layers.
All fill placed must be at least two percent above optimum moisture
content and be compacted to at least 90 percent r~paction_.
If possible, excavations from claystone areas should be placed in
the deeper fill areas. As fills proceed up slope they should be
properly benched and keyed to the original ground.
14. During cutting operations, non-expansive soil should be stock-
piled for capping building pads and/or street sections.
15. Building pads which contain a cut-fill daylight line should be
overexcavated by two feet. Pad entirely in cut sections should be
scarified eight inches, moisture conditioned, and recompacted to
at least 90 percent relative compaction. If sufficient on-site
non-expansive material is available, cut pads which possess expansive
material should be overexcavated two feet and be capped with non-
expansive soil.
16. The top two feet of fill in building pads should consist of
non-expansive soil if possible. If not possible, consideration
should be given to lime treatment or other forms of stabilization
to reduce expansi~e potential.
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GEOCON --
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File No. D-0364-S01
June 6, 1975
Slabs-on-grade
20. Minimum slab reinforcement should consist of 6 x 6 10/10 wire
mesh located at the center of the slab. The slab should be under-
lain by one to two inches of sand over impervious membrane.
21. If sufficiently expansive soil is present, the slab reinforce-
ment should be increased by 6 x 6 wire and the bedding under the
slab increased to six inches. In addition, presoaking of the slab
will be required.
Drainage and Maintenance
22. Good drainage is imperative, to control both expansiveness and
erosion. All pads must have drainage swales which direct storm
and irrigation water away from the structures and into street gutters
or other drainage facilities. No water should be allowed to
pond adjacent to footings.
23. If downdrains are used, they should discharge into splashblocks
and into the aforementioned swales .
24. Effective maintenance of slopes is essential. In our experience,
a well controlled planting and irrigation system is superior to a
bench and drain design.
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GEOCON
lNCORPORATEll
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File.No. D-0364-SOl
June 6, 1975
I 25. No storm or irrigation water should be allowed to discharge
over cut or fill slopes.
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26. Siltation basins should be provided if the rainy season
occurs during grading or prior to the establishment of ground
cover on slopes.
27. In unbuttressed claystone cut slopes (such as along the proposed
street at the north end of the project), small "popout" slope failures
may occur due to the elimination of overburden stresses particularly
during wet seasons or at the time of heavy irrigation. Maintenance
and/or replanting of these areas is essential to control excessive
slope debris.
Grading Plan Review
28. The soil engineer and engineering geologist should review the
final grading plans to verify its compliance with this report and
with U.B.C. Chapter 70 as required by the State of California
Division of Real Estate. ~ ~ ~-
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File No. D-O364-SOl
June 6, 1975
LIMITATIONS AND UNIFORMITY OF CONDITIONS
1. The recommendations of this report pertain only to the site
investigated and are based upon the assumption that the soil
conditions do not deviate from those disclosed in the borings. If
any variations or undesirable conditions are encountered during
construction, or if the proposed construction will differ from that
planned at the present time, Geocon, Incorporated, should be notified
so that supplemental recommendations can be given.
2. This report is issued with the understanding that it is the
responsibility of the owner, or of his representative, to insure
that the information and recommendations contained herein are
brought to the attention of the architect and engineer for the
project and incorporated into the plans, and that the necessary steps
are taken to see that the contractor and subcontractors carry out
such recommendations in the field.
3. The findings of this report are valid as of the present date.
However, changes in the condition 0£ a property can occur with the
passage of time, whether they be due to natural processes, or the
works of man on this or adjacent properties. In addition, changes in
applicable or appropriate standards occur, whether they result
from legislation or the broadening of knowledge. Accordingly, the
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GEOCON
INCORPORATE I>
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File No. D-0364-S01
June 6, 1975
findings of this report may be invalidated, wholly or partially,
by changes outside of our control. Therefore, this report is
subject to
one year.
review and should not be relied upon after a period of
~~l:J76/
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GEOCON
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File No. D-0364-S01
June 63 1975
Sunnnary of In-Place
Sample
No. Location
Bag 1 T-1, el. 200'
Bag 2 T-1, el. 185'
Bag 3 T-1, el.130'
Bag 4 T-2, el.145'
1-1 B-1, el.172 I
1-2 B-1, el.149'
TABLE I
Moisture-Density and Direct Shear Test Results
Angle of
Dry Moisture Unit Shear
Density Content Cohesion Resistance
e.c.f. % E· s. f. degrees
117.7 10.0
122.0 12.4 370 31
100.7 22.0
117.8 14.7
115.9 11.6 900 39
106.8 18.2 450 31
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GEOCON
INCORPORATED
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File No. D-0364-S0l
June 6, 1975
Stumnary
Sample Description
No.
of
1-1 Medium Grained
SAND
1-2 CLAYSTONE
Bag 2 Clayey SILT-
STONE
TABLE II
Laboratory Expansion Test
Moisture Content
Before After
Test Test
Depth
Ft. % %
20 10.0 11. 0
41 14.6 22.5
See 12.9 24.0
Log T-1
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Results
Expansion(+)
or
Dry Settlement{-2
Density Surcharge
p.c.f. % p.s.f.
115.9 +0.1 144
117.4 +13.6 144
108. 0 +7.7 144
GEOCON
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File No. D-0364-S0l
June 6, 1975
CEPTH SAMPLE LOG a ~trotion
IN NO. LOCATION R~1stc;-.c1
OF ;;-
FEET SAMPLE Blows/ft
•0 • . . . . ·-· j :· I _.
. . . . . . ·.I ..
·2 . ):~ /·.·'.: . . . .. -~ --
2-1 :.·.::·=· .· .. ·~. : ·4 . /;/.. • _. .;,/·
• . ·/·. -;.;."/. ·6 . /-"/: . . /..·./-;,_ • ..
1/· ,· ·s . ;:; 2-2 5/12 -. • • /.·:i •10· -/,-;,,.": . . .
C . --✓-. / .• .. . . . ~
·12 • :/· .··_·/ ... . . ·/.··
•14· •'
":).-(.
DESCRIPTION
BORING No. 2
Loose, damp, light grey brown
Silty SAND
Qal
-------
Very loose, moist, light brown
\ coarse, clean SAND
Loose, moist, grey brown Clayey
SAND ALLUVIUM
Medium dense, damp, grey brown
Clayey SAND
Qsw
Medium dense, moist, light brown
medium grained Clayey SAND
Qsw
. . ··</·· 3.5/12" 2-3 ..
·/_ / •16 • . . Boring terminated at 16 feet
. . . . . . . . . .
C . . .
. . . .
. .
. .
Figure 7 -Log of Test Boring No. 2
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IN-PLACE
ORY MOISTURE
DENSITY CONTENT
pc.f. %dry wt.
102.9 15.7
111. 2 12.1
110.4 18.3
GEOCON
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File No. D-0364-S01
June 6, 1975
OEPTH SAMPLE LOG a Pe:letrct10n
IN NO. LOCATION Reo,slalee
OF FEET SAMPLE Blows/fl
o. le ~ . •
. 2. ~ . .
• 4.
/-1//. • . . /. . . 3-1 /, 1/ 3/12
. 6. /·~-• .
• 8 • y_; . . ·/.·j.
•10 • 3-2 /· 5/12
• .
·12 ° ·/.···_. . .
, . . :/-·/
·14 • /·).
.. . .
·16 • . . . .
. . . .
• . . .
. .
. .
. . . .
. .
. .
DESCRIPTION
BORING No. 3
Firm, moist, dark brown Sandy
CLAY
(slopewash)
Loose, medium dense, moist,
grey brown, Clayey fine to
medium grained SAND
(slopewash)
Grading to Sandy CLAY
Boring terminated at 15 feet
Figure 8 -Log of Test Boring No. 3
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IN-PLACE
ORY MOISTURE
DENSITY CONTENT
pe.f. o/odty wt.
110.8 12.3
111. 3 8.6
GEOCON
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File No. D-0364-S01
June 6 .• 1975
-...,: 120
0
ci ->., -Cl) 115 C cu
C
>-...
C
8 10 12 14
Moisture Content -(% of Dry Weight)
Sample : Trench 1, Bag 2 Elev = 185'
Description : Hard, dry s ILTSTONE
16
Laboratory Test Procedure : ASTM D155 7-70, Method A
Maximum Dry Density : 120.3 p.c.f.
Optimum Moisture Content • 12.3%
Figure 11 -Laboratory Compaction Test
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GEOCON
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File No. D-O364-SO1
June 6, 1975 ..
RECOMMENDED GRADING SPECIFICATIONS
for
Carlsbad Meadows
Carlsbad, California
1.1 General Description
1.11 These specifications have been prepared for grading and site
development of Carlsbad Meadows which is located east of
La Portolada Drive and north of the extension of Tamarack
Avenue in Carlsbad, California. Geocon, Incorporated,
hereinafter described as the Soil Engineer, should be consulted
prior to any site work connected with site development to
insure compliance with these specifications. These specifications
shall only be used in conjunction with the soil report of which
they are a part.
1.12 This item shall consist of all clearing and grubbing, prepara-
tion of land to be filled, filling of the land, spreading,
compaction and control of the fill, and all subsidiary work
necessary to complete the grading of the filled areas to con-
form with the lines, grades, and slopes as shown on the accepted
plans.
1.13 In the event that any unusual conditions not covered by the
special provisions are encountered during grading operations,
the soil engineer shall be immediately notified for direction.
The soil engineer shall test and observe all grading operations.
2.1 Tests
2.11 The standard test used to define maximum density of all com-
paction work shall be the ASTM Test Procedure No. D1557-7O.
All densities shall be expressed as a relative compaction in
terms of the maximum density obtained in the laboratory by
the foregoing standard procedure.
3.1 Clearing, Grubbing, and Preparing Areas to Be Filled
3.11 Any trees not utilized in landscaping, structures, weeds, and
other rubbish shall be removed, piled, or otherwise disposed
of so as to leave the areas that have been disturbed with a
neat and finished appearance, free from ·unsightly debris.
-33-GEOCON
l~CORPORATEU
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File No. D-0364-S01
June 6, 1975
3.12 Any septic tanks, if encountered, and debris must be removed
from the site prior to any building, grading, or fill operations.
Septic tanks, encluding all connecting drain fields and other
lines, must be totally removed and the resulting depressions
properly reconstructed and filled to the complete satisfaction
of the supervising soil engineer.
3.13 All ·water wells on the site shall be capped according to the
requirements of the San Diego County Health Department. The
strength of the cap shall be at least equal to the adjacent
soil. The final elevation of the top of the well casing must
be a minimum of 36 inches below any adjacent grade prior to any
grading of fill operations.
3.14 All buried tanks, if encountered, must be totally removed and
the resulting depressions properly reconstructed and filled
to the complete satisfaction of the supervising soil engineer.
3.15 All vegetable matter, and soil designated as unsuitable by
the soil engineer, shall be removed under the direction of
the soil engineer. The then exposed surface shall then be
plowed or scarified to a depth of at least eight inches and
until the surface is free from ruts, hummocks, or other uneven
features which would tend to prevent uniform compaction by
the equipment to be used.
3.16 The original ground upon which the fill is to be placed shall
be plowed or scarified deeply and where the slope ratio of
the original ground is steeper than six horizontal to one
vertical, the bank shall be stepped or benched. At the toes
of the major fills and on the sideslope fills, the base key
shall be, as described elsewhere in this report, at least
10 feet in width, cut at least three feet into the undisturbed
or native soil, and sloped back into the hillside at a gradient
of not less than two percent. Subsequent keys should be cut
into the hillside as the fill is brought up the slope. The
construction of subsequent keying operations shall be determined
by the soil engineer during grading operations. Ground slopes
which are flatter than six to one shall be benched when con-
sidered necessary by the soil engineer.
3.17 After the foundation for the fill has been cleared, plowed,
'or scarified, it shall be disced or bladed until it is uniform
and free from large clods, brought to the proper moisture
content by adding water or aerating, and compacted to relative
density of not less than 90 percent.
-34-
GEOCON
l..,.C-ORP0RATEll
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File No. D-0364-S01
June 6, 1975
4.1 Materials
4.11 Native soil, free of organic material and undesirable deleterious
material may be used as fill. Native soil which is expansive
shall not be placed on the top two feet of building pads with-
out the approval of the soil engineer.
4. 12 The materials for fill shall be approved by the soil engineer
before commencement of grading operations. Any imported material
must be approved for use before being brought to the site. The
materials used shall be free from vegetable matter and other
deleterious material and be non-expansive. Expansive soil is
defined as soil which expands more than three percent when
saturated at 90 percent relative compaction and optimum
moisture content under a surcharge of 150 p.s.f.
5.1 Placing, Spreading, and Compacting Fill Material
5.11 The selected fill material shall be placed in layers which,
when compacted, shall allow adequate bonding and compaction.
Each layer shall be spread evenly and shall be thoroughly
blade mixed during the spreading to insure uniformity of material
in each layer.
5.12 When the moisture content of the fill material is below that
specified by the soil engineer, water shall be added until the
moisture content is as specified to assure thorough bonding
during the compaction process. When the moisture content of
the fill material is above that specified by the soil engineer,
the fill material shall be aerated by blading or other satis-
factory methods until the moisture content is as specified. All
material will be placed at a moisture content at least two
percentage points above optimum moisture content.
5.13 After each layer has been placed, mixed, and spread evenly,
it shall be thoroughly compacted to a relative compaction of
not less than 90 percent.
5.14 When fill material includes rock, no rocks will be allowed
to nest and all voids must be carefully filled with small
stones or earth and properly compacted. No rocks larger than
four inches in diameter will be pennitted in the fill.
5.15 Compaction shall be by sheepsfoot rollers, multiple-wheel
pneumatic-tired rollers or other types of acceptable compact-
ing rollers. Rollers shall be of such design that they will
be able to compact the fill to the specified moisture content
range. Rolling of each layer shall be continuous over its
entire area and until the required density has been obtained.
-35-GEOCON
I N C (.) R P (l R AT E 11
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File No. D-0364-SOl
June 6 _. 1975
5.16 Field density tests shall be made by the soil engineer.
Where sh.eepsfoot rollers are used the soil may be disturbed
to a depth of several inches. Density tests shall be taken
in compacted material below the disturbed surface. When these
tests indicate that the density of any layer of fill or portion
thereof is below the required 90 percent density, the particular
layer or portion shall be reworked until the required density
has been obtained.
5.17 The fill operation shall be continued in compacted layers, as
specified above, until the fill has been brought to the
finished slopes and graded as shown on the accepted plans.
5.18 Fill slopes shall be compacted by means of sheepsfoot rollers
or other suitable equipment. Compaction operations shall be
continued until the slopes are stable.
5.19 All earthmoving and working operations shall be controlled to
prevent water from running into excavated areas. All water
shall be promptly removed and the site kept dry.
6.1 Supervision
6.11 Supervision by the soil engineer shall be made during the fill
and compaction operations so that he can certify that the fill
was made in accordance with the accepted specifications.
7.1 Seasonal Limits
7.11 No fill material shall be placed, spread, or rolled while it
is at an unsuitable high moisture content or during unfavorable
weather conditions. When the work is interrupted by heavy rain,
fill operations shall not be resumed until field tests by
the soil engineer indicate that the moisture content and density
of fill are as previously specified.
-36-GEOCON
1:--.C'ORPORATEO
GEOCON
INCORPORATED
File No. D-Q16it-S02
Septemberzz;-f976
Mr. Amos Sormners
ENGINEERS AND GEOLOGISTS • CONSULT ANTS IN THE APPLIED EARTH SCIENCES
Sommers Development Corporation
Post Office Box 1754
Rancho Santa Fe, California 92067
Subject: Carlsbad Meadows Unit 1
Sierra Morena Boulevard
Carlsbad, California
TESTING AND OBSERVATION SERVICES DURING GRADING OPERATIONS
FINAL REPORT OF WORK FROM 8/16/76 THROUGH 9/7/76
Dear Mr. Sormners:
In accordance with your authorization our firm has performed
testing and observation services during grading operations on
the subject project. These services included:
a. engineering observation of the grading operations,
including observation of the removal and/or processing
of the loose topsoils, uncompacted fill, and alluvial
materials encountered.
b. the taking of field density tests in the fill placed
and compacted within the subject site.
c. geologic observation of the cut slopes during the
grading operations.
Site preparation, compaction, and testing were performed between
August 16, 1976 and September 7, 1976 in accordance with recom-
mendations set forth in a soil and geologic investigation prepared
by Geocon, Inc. dated June 6, 1975.
Areas of loose or saturated soils in canyon areas were removed
until firm natural ground was reached. The then exposed ground
surface which was to receive fill was properly benched, scarified,
moisture conditioned, and recompacted. In-place density tests
performed by our firm indicated relative compactions of at least
90% were being obtained. Fill derived from on-site cutting
■ 6645 CONVOY COURT • SAN DIEGO, CALIFORNIA 92111 • PHONE (714) 292-5100
:est ,. _,Q.
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File No. D-0364-S02 September 22, 1976
TABLE I
Summary of Laboratory Compaction Test Results
Soil
Tvpe·
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4
Date
1976
8/18
II
II
8/19
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II
II
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8/20
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II
II
Source & Description Max. Dry Density Optimum Moisture
ecf % dry wt.
Yellow Silty Clayey SAND 117.2 13.4
Dark brown Sandy CLAY 118.5 12.5
Dark brown Silty Clayey SAND 119.8 11.5
Light brown, n;iedium-grained 123.8 12.8
SAND
TABLE II
Summary of Field Density Test Results
Location & Elevation· Dry Dens, Moisture Rel. Comp. Soil Type
pcf % dry wt. % of max. & Remarks
Lot 26 70 108.3 18.3 91.1 2
Lot 33 72 111.3 15.1 93.2 4
Lot 24 72 109. 3 17.4 92.1 2
Lot 31 77 111.3 16.2 93.9 2
Lot 20 72 117.3 14.7 94.7 4
Lot 30 80 112.1 15.7 90.5 4
Lot 20 76 109.6 17.1 92.4 2
Lot 23 80 109.6 18.9 92.4 2
Lot 32 82 106.7 13.4 90.0 2
Lot 28 83 105. 6 11. 7 90.l 1
Lot 33 78 108. 9 14.0 91.8 2
Lot 31 84 .110.2 13.2 92.9 2
GEOCON
INCORPORATED
File No. D-0364-S02
September 21, 1976
il
TABLE II (Continued)
Test Date Location & Elevation Dry Dens. Moisture Rel. Comp. Soil Type
No. 1976 e.c.f. % dry wt. % of max. & Remarks
13 8/20 Lot 25 78 113.9 14.3 96.1 2
14 II Lot 20 81 106.4 11. 7 90. 8 1
15 II Lot 27 84 112.1 14.2 94.5 2
16 II Lot 27 88 117.2 12.5 94.7 4
17 II Lot 24 80 112.2 13.6 90.6 4
1"8 II Lot 24 86 120.7 14.8 97 .5 4
19 8/24 Lot 10 86 112. 8 13. 0 95.2 2
20 II Lot 13 88 114. 9 13.2 92.8 4
21 II Lot 23 87 117.3 14. 7 94.7 4
22 8/25 Lot 28 90 118.7 13.9 95.9 4
23 II Lot 29 95 119.6 13.2 96.6 5
24 II Lot 22 89 114.2 14.2 92.2 4
25 8/26 Lot 38/offsite 82 106.9 9.2 90.2 2
26 II Lot 40/offsite 85 108.1 11.2 91.2 2
27 II Lot 32 95 108.2 11. 6 91.3 2
28 II Lot 30 93 116.8 12.0 94.3 4
29 II Lot 26 93 118.2 14. 0 95.4 4
30 II Sierra Morena 94 117.7 13.9 95. 0 4
Opp. Lot 27
31 8/27 Lot 12 91 110.0 12. 0 88.0 4*
32 II Retest {f31 91 111. 8 13. 6 90.3 4
33 II Lot 15 94 114.7 14.4 96.7 2
34 II Lot 11 95 110.0 12.2 92.8 2
35 II Lot 14 99 117.2 11. 7 94. 7 4
36 II Lot 8 94 115. 6 12.6 93.6 4
37 II Lot 34 97 112.3 12.2 94. 7 2
38 8/28 Lot 37/offsite 91 112.3 93.6 94.7 2
39 II Lot 17 100 114. 7 14.1 96.8 2
*Indicates Test Failure
GEOCON
INCORPORATED
File No. D-0364-S02
September 22, 1976
..
TABLE II (Continued)
Test Date Location & Elevation Dry Dens. Moisture Rel. Comp. Soil Type
No. 1976 2.c.f. % dry wt. % of max. & Remarks
40 8/28 Lot 21 90 117.7 13.9 95 .1 4
41 II Lot 39/offsite 92 105 .1 12.3 90.0 1
42 9/1 Lot 19 FG 116.0 8.1 93.7 4
43 " Lot 18 " 120. 8 10.2 97.6 4
44 " Lot 17 " 118.9 10.2 96.0 4
45 II Lot 16 " 121. 6 12.0 98.2 4
46 II Lot 15 II 115.7 8.4 93.5 4
47 " Lot 14 " 118.9 9.6 96.0 4
48 " Lot 13 II 116.0 8.1 93.7 4
49 " Lot 12 " 120.7 10.5 97 .5 4
50 " Lot 11 " 122.2 14. 0 98.7 4
51 II Lot 10 II 112.8 8.4 91.1 4
52 " Lot 9 " 117.0 9.9 94.5 4
53 II Lot 8 " 119.2 10.5 96.3 4
54 II Lot 7 II 119.4 10.2 96.4 4
55 " Lot 6 " 118.2 9.6 95.5 4
56 " Lot 5 II 116.6 8.1 94.2 4
57 II Lot 4 II 114.9 7.8 92.8 4
58 II Lot 3 " 116.5 8.7 94.1 4
59 9/2 Lot 25/Storm +3 116.5 8.1 94.1 4
drain backfill
60 " II " +7 115.8 7.7 93.5 4
61 II II II +11 115.7 14.5 93.4 4
62 9/7 Lot 34 FG 117.6 10. 5 95.0 4
63 II Lot 33 FG 115.5 7.8 93.3 4
64 II Lot 32 FG 114.1 7.8 92.2 4
65 II Lot 31 FG 117.0 8.1 94.5 4
66 II Lot 30 FG 117.2 10. 2 94. 7 4
67 II Lot 29 FG 116.0 7.5 93.7 4
68 II Lot 28 FG 115.4 7.8 93.2 4
GEOCON
INCORPORATED
·' ' '
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Test
No.
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File No. D-0364-S02
September 22, 1976
TABLE II (Continued)
Date Location & Elevation
1976
9/7 Lot 27 FG
II Lot 26 FG
II Lot 25 FG
II Lot 24 FG
II Lot 23 FG
II Lot 22 FG
II Lot 21 FG
II Lot 20 FG
II Lot 2 FG
II Lot 1 FG
Dry Dens. Moisture Rel. Comp. Soil Type
e.c.f. % dry wt. % of max. & Remarks
113.5 7.5 91.7 4
113.5 7.5 91.7 4
112 ."3 7.3 90.7 4
115.4 8.1 93.2 4
120.4 10.5 97.3 4
113.4 7.8 91.6 4
117.2 7.8 94.7 4
115.9 7.5 93.6 4
117.1 7.5 94.6 4
113.9 7.3 92.0 4
GEOCON
INCORPORATED