HomeMy WebLinkAbout68-18; LAGUNA RIVIERA NO. 3; GEOLOGIC RECONNAISSANCE; 1967-01-10-:•5; J-J;c 4
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A3 AWAM WOOoWARD•CLYDESHERARD & ASSOCIATES pJ0.
Southern CaliforniaOperations
CONSULTING ENGINEERS AND GEOLOGISTS
3467 Kurtz Street, - january 10, 1967
SanD.go - Project C&Iforni 92110 - -
(714) 224-2911
Kamar Construction Company, Inc
325 Elm Avenue
P.O. Box 7l -
Carlsbad, California
Attention: Mr. Jerry L. Rombotis
LACUNA RIVIERA ESTATES SUBDIVISION
UNIT NO. 1 U
CARLSBAD, CALIFORNIA
In accordance with our proposal dated December 20, 1966 and your
letter dated December 22, 1966, we have made a geologic reconnaissance
of the subject site in connection with our review of the report
entitled "Foundation Soils Investigation for the Proposed Rancho Aqua
Hedionda Subdivision" dated July 29, 1965 prepared by Dresseihaus
Engineers. In addition, we have made a supplementary investigation
of the proposed golf course area along the eastern side of the site.
It is our understanding that 6 to 10 feet of fill 1s to be placed
in the previously proposed golf course area and that the proposed
construction in this area will be limited to one and two story
residential, wood-frame structures supported on continuous footings
or a pier and grade beam foundation with a raised floor or a slab-on-
grade floor.
On December 27, 1966, Mr. Richard While, Staff Engineering (eoloqist,
of our office, made a geologic reconnaissance of the site and super-
vised the drillinq of three test borings. The test borinas were
made with a 6-inch diameter power auger at the approximate locations
shown on the attached Site Plan, Figure 1. FIeld loqs were prepared
by the geologist on the basis of an Inspection of the samples secured
and of the excavated material. The Logs of Test Borings shown on
Figure 2 are based on an Inspection of the samples, on the laboratory
test results, and on the field logs. The vertical position of each
sample is shown on the Logs of Test Borings.
The test borings were located in the field with the aid of a "Revised
Tentative Map-Laguna Riviera" dated January 20, 1965, prepared by
Roy L. Klema, Engineers, Inc.
- - -
Kamar ConstructCompanv, Inc.
Project No. 66-237
January 103 1967
Page
The soils encountered in the test borin
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evaluated with respect to strength, swe
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,
characteristics, dry density and moist
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.
T
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of these soils was substantiated by th
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characteristics of a representative samp
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of the soils was evaluated by means of u
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on selected samples and by consideration
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content of the samples and the penetra
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.
Compressibility characteristics were es
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test on a relatively undisturbed samp
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.
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content and dry density determinations
a
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tests are shown with the penetration
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corresponding .sample location on the Logs of Test Borin
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.
T
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of the consolidation test and the plasticit
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c
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nresented on Fioure 3.
SITE, SOIL AND GEOLOnIC CONDITIONS
The. proposed subdivision is located on
a
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to the northeastern end of Aqua Hediond
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b
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a
p
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elevations 10 and 260 feet. The topogra
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generally north-south trending ridges
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the lagoon edge. These ridges are sepa
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relatively narrow canyons; a flat bottom
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3
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extends along the eastern boundary. Th
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covered with grasses with some small br
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.
At the time of the investigation, Park
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a sewer line placed within its limits
.
A general reconnaissance of the site
a
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the previously noted soil report by o
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generally consist of 0 to 5 feet of a
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overlying the relatively dense and ha
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,
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,
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sandstones of the San Mateo formation of
P
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.
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soil mantle reaches a thickness in exces
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mate elevation of 80 feet, the San Ma
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composed of siltv,coarse to medium sa
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and sandy clay layers. Below elevation 80 feet, the format
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is silty clay and sandy silts Interbedde
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pebbly sand beds. These lower strata ar
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and the clay zones may be slide susceptib
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slide in the relatively steep cut bank a
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and Park Drive in the extreme western
p
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.
The test borings made for the supplemental investigation indicate that the subsoils in the broad valley along t
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consist of alluvial materials which are c
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sandy clays, with some thin layers of loose to
m
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to the maximum depths explored, approximatel
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-2-
,, tçp;
- - --. ----- -
Kamar Construction •pany, Inc. S
Project No. 66-237
January 10, 1967
Page 3
to dense sandy gravel-was encountered in Test Boring 1 at a depth of
approximately 8 feet. The ground water level In Test Borings 2 and 3
was encountered at a plan elevation of apnroximately + 7 to + 9 feet
at the time of drilling. No water was encoutitered in Test Borinri 1.
DISCUSSION AND CONCLUSIONS
Based on a review of the soil Investiqation report dated July 29, 1965,
prepared by Dresseihaus Engineers and a geologic reconnaissance of the
area,. it is our oninion that the above-noted renort should orovide a suit-
able basis for the proposed grading and construction ooerations at the
subject site.
The suonlemental test borings made by hloodward, Clvle, Sherard ?
Associates indicate that the near surface subsoils along the eastern
portion of the site consist of slightly compressible fine sandy, clays
interbedded with some loose to medium dense sand layers. It is estimated
that settlements in the order of 1 to 2 inches will occur in this area
under the proposed fill loads of 6 to 10 feet. Most of this settlement
should take niace within 2 to 4 weeks after completion of fillin'i.
PECOMMENDAT,I ONS
1. It is recommended that all grading be done under the observation of
a soil engineer and in accordance with the attached "Earthwork Specifications."
2. It is' recommended that in the valley along the eastern nortion of
the site a waiting period of approximately 4. weeks be renuired after the
completion of gradino and before the start of construction in order to
allow for settlement and stabilization of this area.
3.. It Is recommended that soft loose and/or porous surface soils not
removed by grading operations be excavated, replaced and reomoacted
before additional fill, footings or slabs are Placed. The maximum depth
of these loose and/or porous soils encountered in the borinris is about
2 feet:, however, the depth of compaction should he controlled in the field
by a oualified Soil Engineer unon visual examination of the exnosed snil.
ou s J. L7R 14129
- RW/LJL/ss
Attachment
4 cc
-3-.
WOODWARD CLYDE - SI4RE AND ASSDCATES
C,b&s!dti,V f42 4n4 Yowtdalion F and
_. . .• . -•- - . -
3 ,'
Ke
P
.80
Pc
.70
0
.60
.50 L
.01 .10 1 10
PRESSURE IN TONS PER SQ. FT.
Initial Dry Density, PCF 93 Initial Void Ratio, E0 .801
Initial Water Content, % 27 Final Void Ratio, Ef .689
Initial Saturation, % 9 Compression Index, C .249
Final Dry Density, PCF 100 Swell Index, C .044
Final Water Content, % 26 Existing overburden ess.,F,TSF .225
Final Saturation, % 100 Max. post pressure, PC,TSF 1.2
Llquio LIMIT - 58
Pt..AsTic LIMIT - 18
I WOODWARD, CLYDE, SHERARD & ASSOCIATES I
CCNSOL;DATION TEST
SAMPLE NO. 2-2 -
LAGUNA RtVERA ESTATES SU8DIVSION UNIT I -í POECT PW. $..257 LCM al.tayw..a ,*,tfl.wv&c SeO.I%tfl.
14 .t•
-',-. -
e . S
EARTHWORK SPECIFICATIONS
I. GENERAL
This specification covers preparation of -the existino surfaces
to receive fills the type of soil suitable for use in 'fills:
the control of compaction and the methods of testing compacted
fills. It shall be the Contractor's responsibility to place,
spread, water and compact the fill in strict accordance with
these specifications. A Soil Engineer shall be the Owner's
representative to inspect the construction of fills. Excavation
and the placing of fill shall be under the direct inspection of
the Soil Engineer; and he shall give written notice of conformance
with the snecifications upon completion of grading. Deviations
from these specifications will be permitted only upon written
authorization from the Soil Engineer. A soil investigation has
been made for this project; any recommendations made in the report
of the soil Investigation or subsequent reports shall become an
addendum to these specifications.
SCOPE
The placement of controlled fill by the Contractor shall include
all clearing and grubbing, removal of existinr, unsatisfactory
material, oreparation of the areas to be filled, snreadinci and
compaction of fill in the areas to be filled, and all other work
necessary to complete the qradinq of the filled areas.
MATERIALS FOR STRUCTURAL FILLS
Materials for comnacted fill shall consist of any material
imnorted or excavated from the cut areas that, in the oninion
of the Soil Engineer, are suitable for use in constructino fills.
The material used in structural fills shall contain no rocks or
hard lumps greater than .6 inches in size and shall contain at
least forty percent of material smaller than one-quarter inch
in size. (Up to 2% of the materials may be greater than 6 inches
but less than 12 inches in size provided they are placed by the
Contractor so that they are surrounded by compacted fines: no
nesting of rocks shall he permitted.) No material of a perishable,
spongy, or otherwise of an improper nature shall be used in filling.
Material placed within 12 inches of the bottom of footings
or 24 inches of the finished floor elevation shall be select material
that contains no rocks or hard lumps and that swells less than 3%
when compacted as hereinafter specified for compacted fill and when
subjected to an axial pressure of 160 pounds per square foot.
Representative samples of material to be used for fill shall
be tested in the laboratory by the Soil Engineer in order to
determine the maximum 'density, optimum moisture content and
classification of the soil. In addition, the Soil Engineer shall
ODWARD - CLYDE - SHERPRD AND hSSOCIATFS
Ctilcg Soil and c4 Cii
- . ---- ---:•;:----- C- r ------1----'- -, -. - - .-.- -'" ::'t -
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determine the approSdmate bearing value of a recomnacted, saturated
sample by direct shear tests or other tests applicable to the
particular soil.
4. During grading operations, soil types other than those analyzed
in the report of the soil investigation may he encountered by the
Contractor. The Soil Engineer shall be consulted to determine the
suitability of these soils.
IV. COMPACTED FILLS
1. (enera1
Unless otherwise specified, fill material shall he comoacted
by the Contractor while at a moistue content near the
optimum moisture content and to a density that is not less
than ninety nercent of the maximum density determined in
accordance with ASTM Test No. D-1557-64T, or other density
methods that will obtain equivalent results.
Potentially expansive soils may be used in fills below a
depth of twenty-four inches and shall he compacted at a
moisture content greater than the optimum moisture content
for the material.
2. Clearing and Preparing Areas to be Filled
(a) All trees, brush, orass, and other objectionable material
shall be collected, oiled and burned or otherwise disposed
of by the Contractor so as to leave the areas that have been
cleared with a neat and finished annearance free from
unsightly debris.
(h) All vegetable matter and objectionable material shall
be removed by the Contractor from the surface upon which
the fill is to be placed and any loose soils shall be
removed or comnacted to the depth shown on the olans
unless otherwise specified in writing by the Soil Engineer.
The surface shall then be plowed or scarified to a minimum
depth of six inches until the surface is free from uneven
features that would tend to prevent uniform comoaction by
the equinment to be used.
(c) After the foundation for the fill has been cleared, plowed
or scarified, it shall be disced or bladed by the Contractor
until it is uniform and free from large clods, brought to
the proper moisture content and compacted as specified for fill
3. Placing, Spreading, and Compacting Fill Material
(a) The fill material shall be placed by the Contractor in layers
that when compacted shall not exceed six inches. Each layer
shall be soread evenly and shall be thoroughly mixed during
the spreading to obtain uniformity of material In each layer.
-
WOGDWARD. CLYDE . SHERARD AND ASSOCIATES
Co.t...U€ng .S01 and Foundtion Engivecn 4r4 G20.jias
.1 S
(b) When the moisture content of the 911 material is below
that specified by the Soil Engineer,'water shall be added
by the Contractor until the moisture content is as specified.
34
When the moisture content of the fill material is above
that specified by the Soil Engineer, the fill material
shall be aerated by the Contractor by blading, mixing,
or other satisfactory methods until the moisture content
is as specified.
After each layer has been placed, mixed and spread evenly,
it shall be thoroughly compacted by the Contractor to
the specified density. Compaction shall be accomnlished
by sheepsfoot rollers, vibratory rollers, multiple-wheel
pneumatic-tired rollers or 'other types of acceptable
compacting equipment. Equipment shall be of such design
that it will be able to compact the fill to the specified
density. Compaction shall be continuous over the entire
area and the equipment shall make sufficient trips to
insure that the desired density has been obtained.
Surface of fill slopes shall be compacted so that the
slones are stable and there shall he no excessive loose
soil on the slopes.
V. INSPECTION
Observations and comnction tests shall he made by the Soil
Engineer during the filling and compactinci operations so that he
can state his opinion that the fill was constructed in accordance
with the specifications.
The Soil Engineer shall make field density tests in accordance
with ASTM Test No. D1556-58T. Density tests shall be made in the
compacted materials below the surface where the surface is disturbed.
When these tests indicate that the density of any layer of fill or
portion thereof is below the specified density, the particular layer
or portions shall be reworked until the snecified density has been
obtained.
VI. PROTECTION OF WORK
During Construction - The Contractor shall properly grade all
excavated surfaces To provide positive drainage and prevent nondinq
of water. He shall control surface water to avoid damaae to
adjoining properties or to finished work on the site. The Contractor
shall take remedial measures to prevent erosion of freshly graded
areas and until such time as permanent drainage and erosion control
measures have been installed.
After Completion - After grading is completed and the Soil
Engineer h1i finished his observations of the work, no further
excavation or filling shall be done except under the observation
of the Soil Engineer.
-.7- WO1AD - LYE * SHERARD AND, ISOPXS
MUNICIPAL ENGINEERING ó MEMBER
VALUATIONS, SURVEYS '' AMERICAN SOCIETY
DESIGN, SUPERVISION RAY v1DN D P. P I E3A L) CIVIL ENGINEERS
CIVIL AND SANITARY ENGINEER
- 770 SO. BElA BLVD, SUITS 203
BElA, CALIFORNIA
52- 41 j,J1
DESCRIPTION OF SCHOOL AND PARK SITE ø
LAGUNA RIVIERA TRACT
CARLSBAD1 CALIFORNIA ' MARCH 9 1 1967 \)
That portion of Lot .I of the Rancho Agua 1-ledionda, in the City
of Carlsbad, County of San Diego, State of California, according to 4"
the Map thereof, No. 823, filed in the Office of the County Recorder
of said San Diego County, more particularly described as follows:
Beginning at the Southerly terminus of that certain course
having a bearing of North 00 39' 25" West and a length of 974.01 feet
said Southerly terminus also being the Easterly terminus of that certain
course having a bearing of North 780 18' 37" East and a length of 663.11
feet according to Record of Survey Map No. 5289, filed in the office
of said County Recorder; thence South 780 18' 37" West along last said
course, 140.00 feet to the true point of beginning; thence continuing
South 780 18' 37" West along last said course, 27_7-11 feet to the beginn-
ing of a tangent curve concave Southeasterly and having a radius of
400.00 feet; thence Southwesterly along the arc of said curve througtta
central angle of 510 54' 09", a distance of 362.35 feet to a point
through which a radial line bears North 35L32 ; thence North
76° 01'17" West, 0-1-9 feet; thence North 50 09' 13" West, 85.00 feet;
thence North 380 31' 59" East, i.2.24 feet;thence North 150 45' 20"
East, 115.00 feet; thence North 21
0 44' 40" West, 399.45 feet; thence
North 590 02' 00" East; 477.13 feet to the beginning of a tangent curve
concave Southeasterly and having a radius of 500 feet; thence North-
easterly along the arc of last said curve through a central angle of 260
00' 17" , a distance of 226.93 feet; thence North 850 02' 17" East,
85.89 feet to a point in the arc of a curve concave Easterly and havin
g
a radius of 1500.00 feet, a radial line through last said point bears
South 850 02' 17" West; thence Southerly along the arc of last said
curve through a central angle of 60 52' 32", a distance of 180.00 feet
to a point of tangency; thence South 110 50' 15" East, 655.33 feet to
the true point of beginning.
Containing 14.202 acres more or less.
Subject to restrictions, covenents and easements of record.
Also subject to easements for future Kelly Drive (84 feet in width),
future Park Drive (68 feet in width) 'and future Hillside Drive (68 feet
i
n
width) as said easements are shown on that certain map of Laguna Riviera
Unit No. 1, having a scale of 200 feet to the inch and Date of Last
Revision March 9 196.7 on file in the office of the City Engineer of said
City of Carlsbad.
Prepared By
1ZaymonR. Ribal
RCE 1136
770 So. Brea Blvd.,
Brea, California
RRR: jp