HomeMy WebLinkAboutCT 76-01; CHESTNUT GARDENS SUBDIVISION; PRELIMINARY SOIL INVESTIGATION; 1976-06-28SOIL AND MATERIAL TESTING LABORATORY i&. OF NORTH COUNTY, INC. l~----~------------~------~----------------4-2-'3-H-A-L-E-A-V-E-.--E-S-C-O-N-O-'-O-C-,-CA--U-t-.9-, 2-0~2--S
",' . ' .... " 28 June 1976 ESCCNOIOC~74~·2~33
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Mr. M. S~ ·~umphreys
P.O. Box 1009
Carlsbad, California 92088
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Re: Job No. 76-50
Dear Mr. Humphreys:
Proposed Carlsbad Tract 76-1
Chestnut Gard~ns·Subdivision
Carlsbad, California
Enclosed is:our Preliminary Soil Invest~gation report as
you requested fOf the above referenced project located on the
i ~ southeast corn er : of Chestnl,lt Avenue and Monroe ·Street , Carlsbad,
California.
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The investigation consists of five test pits dug to ~epths
of approximately 5 to 7 feet below the existing_ground surface •
Appropr'i.ate'.labo~atory testing' and engineering analyses were·
performed.
The ,results of this investigation along with our recommen ...
dations are to be found in the aricompanying report. In summary,
it is our opinion that th~re are no unusual soil groblems which
would hinder the'gradingof the proposed p~oject provided our
recommendations are followed. We wish to emphasize the importance
of continuing inspection and testing during grading.
If there are any questions or problems, please f~el free to
contact us in the future.
Respectfully submitted,
SOIL AND MATERIAL TESTING
LABORATORY OF NORTH COUNTY, INC.
~g'fZ
CLAUDE B. PARKER ~ .
Registered Civil Engineer #1S,987
Certified Engineering Geologist #922
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RECEIVED
JUL ~8 1976
CITY OF CARLSBAD
En!ineerin~ Department
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I' PRELIMINARY SOIL INVESTIGATION
! PROPOSED CARLSB8D TRaCT 76-1
CARLSBAD, CALIFORNIA .
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! MR. M. S. HUMPHREYS
P.O. 'BOX 1099
CARLSBAD, CALIFORNIA , 92008
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-.28 JUNE 19_7.p
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i JOB NO. 76-50
sOIL AND MA~RIAL TESTING LABORATORY
.1 DP' NDRT'" CD4NTY. INC.
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II.
III~
T~BLE OF CONTENTS
General Information
Purpose of Investigation
Field Investigation
A. Surface_ Conditions
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B •. Test Pits
C. Subsurface Conditions
IV~ Tests and Results
A. Density Tests
B. Expansion Test
C. Direct Shear Test
V. Bearing Capacity
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VI. Conclusions and Recommendations 5
I VI I. R(3ference 7
APPENDIX
Plot Plan
Logs of Test Pits
Specification for Con~truction
of Controlled-Fills
Unified Soil Classification Chart
Pla.te
2 to. 5
SOIL AND MATERIAL TESTING LABORATORY
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I PRELIMINARY SOIL INVESTIGATION
PROPOSED CARLSBAD TRACT 76-1
CHESTNUT GARDENS
~ARLSBAD, CALIfORNIA
GENERAL INFORMATION
A preliminary soil investigation has been completed for the
proposed Chestnut Gardens subdivision legal~y described ~s Carlsbad , ' ,
Tract 76-1, City' of Carlsbad, County of Sc;ln Diego, State of' C,alifornia.
It is understood the land is planned, to be used for four new
residential hous'e pa,ds. The existing, house on Lot 6 will remain.
The' buildings will be one and two-story wood frame dwellings. The
foundations wil~ consist of concrete ~labs~on-grade wiih continuous
concrete wall footings~ Due to the relative flatness of the topo~
graphy, the cuts and fills should be small'~lthough details of the
structures or grading 'were not available at the writing of this
report.
PURPOSE OF INVESTIGATION
The purpose of this investigation is to determine the following:
1 -the conditidn of the native soil"
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the presence and condition of any exp~nsive soil or
existing fill,
the allowable ibil bearing pressures,
4 any obvious geologic hazards,
6 -any construction problems that can be anticipated,
and to ma~e appropriate foundation recommendations.
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III. 'FIELD INVESTIGATION
A. Surface Conditions
The site is fairly level with a slight slope up towards the
east. 'The site 'is covered with loose sand and spars~ weeds. Except·
for the house arid garage on Lot 6 the site is devoid Qf any featutes
SOIL AND MATERIAL '!'ES'l'ING LABORATORY
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i which would cau~e problems cluring grading.
i There were'no obvious landslides, faults or other geQlogic ,
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hazard-o observed dl:.lring the investigation. A review of the liter:" , ,
I ature indicates i the site is in a relat~vely stable area for SouthJ3,rn
California. The nearest "active" faults are reported to be at l,east
" 30 to 40 miles away to the east and south.
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B. Test 'Pits I
Five explotatory test pits were dug ~ith'a backhoe on 24 June ,
1976 at the approximate locations indicated on Plate 1 (from the ! '
Map by E. Brian ISmith, Engineersj CarLsbad). Samplea of the sQil~
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were visually c::~assi fied by fi·eld identi fication. procedure in ac.cord-
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ance with the Unified Soil Classification. A simplified veraion of
the Unified Soil Classification is included in the Appendix. Con-
tinuous logs of the soils encountered in the test pits were recorded'
in the field. The logs of the test pi~8 shown on Plates··2 to 5 are.
based on the field logs, pn inspe6tion of. the samples, and on the
i laboratory test results.
C. subsuiface Qonditioris
The site is underl~in b~ a fairly unifor~-soil profile generally
consisting of approximately 2 feet of granular silty sand then one
to two feet of stiff sandy clay which grades to a firm cl~yey sand.
No groundwater or hard rock was encountered.
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There we'rsessentially three soil types baSed on similar engin-
eering properties as describeq on the logs which were encountered
during the investigation. The three soil types are referred to later
in the report as Soil Types 1, 2, and 3.
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, . SOIL AND MATER1AL TESTING LA,.BORATORY
'" ' ! Dr N9flT!"I CPL!~.TY, INC~. ! .
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Soil 'Soil .1 Type 'Description
1 Brown Silty Sand
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2 'Brown Gray Sandy Clay
3 Red Brown Clayey Sand
IV. TESTS AND RESULTS
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A. Density Tests
1 -Laboratory Compaction
One laboratory compa.ction test was mad-e of Soil Type 1
to determine the maximum dry densities and optimum moisture
content of this material as spedified by ASTM D1557-64T
(method A). This test 'uses the minus #4 sieve soil ina4
inch diameter 4 inc~ high cylindrical mold. The sample is
formed with a 10 pound hammer falling 18 inches for 25 blows ,
on each of 5 layers.
LABORATORY COMPACTION
Location Soil Max.Dry Optimum
Type . Densi ty Moisture
(pcf) . Content (%)
Test Pit 2 ®.1' 1 1'2.7.5 8.8
2 -DBnsity Tests ,.
I,.! :IMois-ture contents and densi.ty determinations were made by
direct measurements on paraffin coated· samples by the water
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displacement method. . ,
The ratio of fLeld dry density to the labo~atory maximum
dry density is defined as the relative compaction. -These res81ts
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are presented on the logs, Plates 2 to 5~
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SOIL AND MATERIA.~ 'l'ES'TING LABORATORY
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B. Expansion Test
An axpansion test was performed on the upper claysy soil, Soil
Type 2 to determine if this material would constitute a str~ctural
hazard to the buildings if fciund near final grade. An undisturbed
ring sample 2i inches in d~ameter and 1 inch high 4as lo~ded with
1 psi, instrumented, and allowed to air dry. After shrinkage ,had
ceased, distilled water was applied and the expansions were r~corded
as a percentage of the air 'dried height. The results follow:
,EXPANSION TEST
Sample
Location
Test Pit 3 @ 3'
Initial Condition
,w ' t
14.0 112.5
w = moisture content (%)
t = dry density (pcf)
Air Dry'
w 'lI'
5.7 114.7
s~turate~. % Expansion
18.3 109.4 4.8 ,
:. "These tests indicate this cla¥ strata is ~.2Spansive , and the
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recommendations ,contained in Section VI, "Conclusions and Recom-
mendation~" sh6uld ~a followed if th~ clay is encounterad within
two feet of final grade.
C. Direct Shear Test
A direct,shear test was performed on' samples of Soil Type 1,
the material in which the footings will be founded, for strength
parameters in the bearing capacity oalculation. Three specimens , :
i of this soil were pre~ared by rsmolding to 9b% of the max~mum dry
density at 3% o~er the optimum moisture content the soil in 2t
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inch diameter 1 linch high rings to the inplace conditions of moisture
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and density. 1 ' The specimens were loaded with normal loads of .5, 1~G,
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and 1.5 KSF respectively and'sheared to failure in Undrained shear.
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I The results follow:
SOlL AND MA'tEBIAL TESTING LABORATORY
Of" NORTH CO~N1'Y, INC,
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;1 DIRECT SHEAR TEST
Location Soil Unit Angle of App'areflt
Type Density Internal Cohesion
(l2 cf) Friction {a} {l2 sf}
Test Pit 2 ® 1 t 'i 1 128 25 220
BEARING CAPACITr
The value's: of internal friction and app'arent cohesion derived
from the direct:shear test were used in the Terzaghi Formula in
a,ccordance with: the p,rocedure outlined in Reference 1, poage '170,
to bom~ute the ~llowable bearing capacity.
Terzaghi Formula
Bearing Capa~ity = 2/3cN' . c
Ass'umptions:
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Depth-of Footing, .D f = 1.0'
Width .of Continuo~s Footing~ B = 1.0'
" Nt Nt N'
j' c' q' J = dimensionless parameters found from
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Soil
Type
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factor of Safety = 3.
ALLOWABLE 'BEARING CAPACITY
Soil
Description
Brown Silty Sand
Bearing,
Capacity {psf}
-1053
VI •. / CONCLUSIONS AN.D RECOMMENDATIONS
1 -It is recommen-ded that all grading and the preparation of
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native soil be ~one in acbordanc~ with the enclosed t'Spebification~
for Construction, of Controlled Fills" except if supe:rseded by the
following recommendations.
Any septic tanks or largs buried qbj~cts encountersd durin~
grading should be excavated and the voids filled with compacted soil.
SOIL AND MATERIAL TESTING LABORATORY
OF' NORTH COU~TY. INC.
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~ -The loose upper, surface soil as indicated on the logs
• should be excavated and recompacted to at.'least, 90% of the maximum
dry density prior to placing the house foundatiOnB or fill. The
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approximate depth of recompaction over the site is in the order Df ,
1 to 1t feet. ,the actual depth should be cpntrolled in the field
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by a qualified soil engineer on examination of the grading plan
ahd actu~l field condition.
3 -Design slope ratios for 1t (horizontal) : 1 (vertical) for
cuts and 2:1 for fills.
4 -the soil tests and theoretical calculations indicate an
allowable bearil!g capacity of 1053 psf.
5 -The expansion tests indicate,the clay layer at 1tto 2 feet
, -below the existing surface can be classified as expansive. If pos-
sible any clay found within 2 faet of final grade should be undercut
2 foot and repl~bed with granul~~ soil whidh is abundant on site •.
J' If clay is/detected within 2 feet of final grade~ the founda-
tion should be strengthened as follows:.
a -Deepen;the footings to 2 feet below the nearest adjacent
,ground level.
b -Reinforce the footing~ with two #5 reinfo~cing rods. Place
one rod 3 in9hes from the bottom and the other 6 inches ftom the top
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of the footings.
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c -Use 6x6/10x10 wire mesh in the slab. Use 6 inches of-clean
sand under the slab and a plastic liner between the sand and slab.
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6 -Direc~ and maintain drainage away from the foundations.
7 -'If soils other t~an those dascribed in this report are
encountered durihg the g~ading or if imported material is uaed,
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SOIL AND MATERIAL 'l'ESTING LABORATOI~Y
O!,: NORTH COUNTY, INC.
VII·.
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additional tests will be required to ascertain their engineering.
properties.
REFERENCE
1 ~ ;erzaghi and PBck, "Soil Mechanics in Engineeting Pra~tice",
John hliley & Son, N.Y. 1948.
Respectfully submitted,
SOIL AND MATERIAL TESTING
LABORATORY OF NORTH COUNTY, INC.
CLAUDE B. PARKER r
Registeied Civil Engineer #1B,987
Certified Engineering Geoiogist #922
I' Distribution: £3 Addressee I i
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SOIL AND MATERIAL TESTING LABORATORY
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TEST PIT LOCATION
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SO~ AND MATERIAL TESTING LABORATORY CI-IESrNUr <5ARDENS
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a,. NaRTH CaUNTY, INC. CARI..SBADTR4CT76-!
.JOB NO. 76-50
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LOG OF BORING
BORING NO. __ T:......;e:;....s ....... t~P..:.i:;....t---.u#.....;1:..-· --'-_
ELEVATION-,-___________ _
SAMPLING B' ackhoe METHOD __ -..:.:;....:;....~~ ______ _
Brown SiltY'Sand
top. 6" loose
firm
Brown Gray Sandy Clay'
stiff
grades sandy
Red Brown Clayey Sand
weakly cemented
Soil Type 1
·Soil Type 3
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6 Undis~urbed Sample
o Disturbed Sample
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Uc = unconfine·d compressure'stren th
by Penetromete~ (T.S.F.)
Date: 24 June 1976 Chestnut Gardens
Carlsbad Tract 76-1
Job No. 76-50
By: C. Parker: Plate No. 2
S4)IL '" MATr:~IAL Tr:STI/III.Ic:1·LAI3()~AT()~."
OF N()RTH COUNTY INC.
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BORING NO. Test Pit #2
ELEVATION _________ _
SAMPLING' METHOD . Backhoe e / ~
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\ Brown Silty Sand
1-6 O· mo:i..st , firm ® 12" f
, 2,--
Soil Typ_e 1
3-Brown Gray Sandy . Clay·
moist &. firm
,6 U = 2.2 TSF
4~ c
I . , grades with clayey sand
5-firm 'Soil Type 2
Red Brown Clayey Sand
6-firm 6 weakly cemented
7 Soil Tvpe -3
,Bottom
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'. Dot~ 24 June 1976 Chestnut Gardens
Carlibad Tract 7S-1 By: ,C. Parker
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Job No.
Plcite No.
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11.6120.0
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S()IL &; M4.TI.:~I4.L TI:STING·L4.I3()~4.T()~'"
O.F NORTH COUNTY INC •
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Date: 24 June 1976.
By: C. Park er:
Chesthut Gardens.
Carlsbad Tract 76-1
Job No.
Plate No.
S()IL &: MATI:I:!IAL TI:STI~G·LAI3()I:!AT()I:!"Y
OF N.ORTH COUNTY INC.
76-50
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I I LOG OF BORING I
, -, Test Pit 11.4 & #5 o.e
BORING NO. z w= '"--~ CL..c:
?; we>< ELEVATION
Q ::> m Z
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-'w If) '" .... 0 .... n.al <{ i5~ Vi ;;: ::r:w ~~ 0'::> v
t-W ~o SAMPLING u:: :E ~ z > v, n.u.. <{::> , w
w "'Z al v Backhoe 'Vi -<{
0 .. METHOD 00 0 ....n. -,If) <{:E -<{ .... ~:s 0 .... ~~ CL. '0.. mo If) v u...~ 0_ o<V
Test 13ft· #'4
, .-Brown Silty Sand : WIW I •••• .. ,-.
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8" · . . 1.6 15.9 90~9 1 -6 j top loose ! : SM ~
firm ® 12" · , , · .. · . · . • ,t •
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TYoe · . · . ,Soil 1 • • · .. · . · ..
6 Brown ~ray Sandy Clay ~
3 -stiff ~ '/;' 12.3 16.2 ~tL; Uc = 4.5 TSF ~A r Soil TVDe 2 4 ,i ~ Red Brown Clayey Sand · .~ · . .. . .
" firm .-. , · .... ~
5 ~ 6 ; j 6-': ~ . . . , · .. -.. -
, Soil 3 ~ .Type .' .... ,~
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7 -Bottom
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0 Test Pit #5 : : : : : Bi'o'wn Siity Sand · .... · : . : :' , , top 12" loose : ~: : : :
1 -· " .. , grades firm ® 18" . · . . , SM,: · • " · , ..... · .....
2 --· . · ":
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3 -
· . Soil Type 1 · . · . . · .. : . • .. I.
I ~ i Brown Gray· Sandy Clay'
4 -I stiff 1/ CL'~
" : ~A 1.< -. Soil Type 2.
5 Bottom ,
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Date: 24 June 1976 Chestnut Gardens Job No. 76-50
By: C. Parker, Carlsbad T~act 76-1 Plate No. 5
S'VI L & M,A TI:I:1IAL TI:STI /illiG .. L4D()I:?A TV 1:1",
OF NORTH COUNTY INC.
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SOIL A.ND MATERIAL TES'l'ING LABORATORY 4i" __________ o_F ___ N_o __ R~T_H __ C __ O_U __ N_T_Y __ ._I_N __ C_. ____________ ~ ______________________ ----~
423 HALE AVE. -ESCONDIDO. CALIF. ~~C2S
ESCONDIDO -746-2333
SPECIFICATIONS FOR C8NSTRUCTIO~OF CONTROLLED FILLS
GENERAL DESCRIPTION: The construotion of controlled fills shall consist
of adequ ate preliminary soi 1 inv esti gations, and cl,earing, removal of
existing structures and foundations, preparation of land to be filled"
excavation of earth and rock from qut area, compaction ~nd control of
the fill, and all other work necessary to complete the gr,ading of the
filled ~reas to conform with the lines, grades, and slopea as shown on
th-e accepted plans.
CLEARING AND PREPARATION OF AREAS TO BE FILLED:
(a) All fill control projects shall have a preliminary soil investigation
or a visual examination, depending upon the nature of the job, by a qual-
ified soil engineer prior to grading.
(b) All timber, trees, brush, vegetation, and other rubbish shall be re-
moved, piled and burned, or otherwise disposed of to leave the prepared
areas with a finished appearance free from unsightly debris.
_iCC) Any soft, swampy or otherwise unsuitable areas,shall be corrected by
.. drainage or removal of compressible material, or both, to the depths in-
dicated on the plans or as directed by the soil engineer.
(d) The natural ground which is determined to be satisfactory for the
support of the filled ground shall then be plowed or scarified to a depth
of at least six inches (6") or deeper ~s spe-Qi fied by the soil engineer,
and until the surface is free from ruts, hummocks, or other uneven fea-
tUfes which would t~nd to ,prevent uniform compaction by the equipment to.
be used.
(e) No fill shall be placed until the prepared native' ground has been
approved by the soil engineer.
(f) Where fills are made on hillsides with slopes greater th~n 5 (hori-
zontal) to 1 (vertical), horizontal benches s-hall be cut into fi:rm un ...
disturbed natural ground to provide lateral and vertical stability. The
initial bench at the toe of the fill shall be at least 10 feet Ln widtb
on firm undisturbed natural ground at the elevation of ths to~ stake.
The soil engineer shall determine the width and frequency of all su:c-
ceeding benches which will vary with the soil conditions and the steep-
ness of slope.
(g) After the natural ground has been prepared, it shall be brought to
the proper moisture content and compacted to not lesa than 90% Of max-e imum density, A.S. T.M. D1557-64T.
.--------------~------·t
(h) Expansive soils may require special oompaction specificatiDns
e'as directed in the preliminary soil investigation by the soil engineer.
(i) The cut portions of ~uilding pads in which rock-like materiaL exists
may require excavation and recompaction for density compatibility with
the fill as directed by the soil engineer.
MATERI~LS: The fill soils shall consist of select materials graded so
that at least 40 percent of the material passes the No. 4 sieve. The
material may be obtained from the excavation, a borrow pit, or by mixing
soila from one or more sources. Th~ material used shall be free from
veg~table matter, and other deleterious substances, and ~hall not contain
rocks or lu~ps greater than 6 inches in diameter. If excessive vegetatiOn,
rocks, or soils with unacceptable physical characteristics are encountered,
these materials shall be disposed of in waste areas designated on the plans
or as directed by the soil engine~r. If soils are encountered during the
grading operation which were not reported in the preliminary soil invest-
igation, further testing will be required to ascertain their enginee-ring
properties. Any special treatment recommended in the preliminary or su·b-
sequent soil reports not co·vered herein shall become an addendum tl:J the-se
specifications.
No material of a perishable, spongy, or otherwise unstable nature shall
be used in the fiils.
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PLACING, SPREADING AND COMPACTI.NG FILL MATERIAL:
ada) The selected fill material shall be pLaced in layers which shall
~not exceed six inches (6") when com~acted. Each layer shall be spread
evenly and shall be thoroughly blade-mixed during the spreading to insure
uniformity of material and moisture in each layer.
(b)
fied
tent
ough
Ulhen the moisture content of the fill material is below·thatspeci-.
by the soil enginee'r, water shall be added until the mois·turecon-
is near optimum as determined by the soil engineer to assure thor-
bonding during the compacting process.
(c) When the moisture content of the fill material is above that speci-
fied by the soil engineer, the fill material shall be aerated by blading
and scarifying, or other satisfactory methods until the moisture content
is n:ear optimum as d-etermined by the soils engineer.
(d) After each layer has been placed, mixed and spread evenly, it shall
be thoroughly compacted to not less than the specified maximum density
in acoordance with A.S.T.M. D1557-64T. Compaction shall be by means of
tamping or sheepsfoot rollers, multiple-wheel pneumatic-tired rollers, or
other typ.s of rollers. Rollers shall be of such design that they will
be able to compact the fill to the specified density. Rolling of each
layer shall be continuous over its entire area and the roller shall m~ke
sufficien.t passes to obtain the desired density. The entire. area to be
filled shall be compacted to the specified density.
SOIL AND MATERIAL TESTING LABORATORY
OF" NORTH COUNTY, INC.
-2-
" (e) Fill slopes shall be compacted by means of sheepsfoot rollers or
_ other sui table equipment. Compacting operations ~hall be co~tihued' u~til
the slopes are stable but not too dense for plant1ng and unt11 there 18
no appreciable amount of loose soil on the slopes. Compacting of the
slopes shall be acc,mplished by backrolling the slopes in increments of
3 to 5 feet in elevation gain or by other methods producing $atisfac~ory
results.
(f) Field density tests shall be made by the soil engineer for approx-
imately each foot in elevation gain after compaction, but not to exceed
two feet in vertical height between tests. The location of the tests in
plan shall be spaced to give the best possible coverage and shall be
taken no farther t'han 100 feet apart. Tests shall be taken on corner
and tert~c8 lots for each two feet in elevation gain. The soil engineer
miy take additional tests as conside~ed necessary to check on ths uniform-
ity of compaction. Where sheepsfoot rollers are used, the tests shall
be taken in the compacted material below the diaturbed surface. No
additional layers of fill shall be spread until the field density tests
indicate that the specified density has been obtained.
(g) The fill operation shall be continued in six inch (6") compacted
layers, as specified above, until the fill has been brought to the fin-
ished slopes and grades as shown on the accepted plans.
SUPERVISION: Supervision by the soil engineer shall be made during the
filling'and compacting operations so that he can 6ertify that the fill
__ was made in accordance wi th accepted speci fications.
The specifications and soil testing of subgradB, subbase, and base
materials fpr roads, or other public property shall be done in accordance
with specifications of the governing agency.
SEASONAL LIMITS: No fill material shall be placed, spread, or rolled
during unfavorable weather conditions. When the work is interrupted
by heavy rain, grading shall not be resumed until field tests by the
soil engineer indicate that the moisture content and density of the fill
are as previously specified. In the event that, in the o'pinion of the
engineer, soils unsatisfactory as foundation material are enoountered,
they shall not be incorporated in the grading and disposit~on will be
made at the engineer's discretion.
SOIL AND MATERIAL TESTING LABORATORY
OF" NORTH COUNTY, INC.
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UNIFIED SOIL CLASSIFICATION .CHART
IDENTIFYING
CRITERIA -'I.
•. : tI.
COARSE GRAINED
(More than 50% #200 sieve)
GRAVELS
(More than 50% #4 sieve
but smaller than. 3 inches)
Non Plastic
SANDS
(More than 50% smaller
than #4 sieve)
Non Plastic
fINE GRAINED (Mor~ than 50% smaller
than #200 sieve)
Liquid Limit
less than 50
Li,quid Limit
greater than 50
HIGHLY ORGANIC SOILS
;
GROUP
SYMBOL
GUJ
GP
GM
GC
SUJ
SP
SM
SC
ML
CL
OL
MH
CH
OH
PT
SOIL
DESCRIPTION
GRAVEL, well graded gra~el
sand mixture, Ii t tIe ot· no
fines.
GRAVEL, poorly graded gravBl-
sand mixture, little or no
fines.
GRAVEL, SILTY, poorly graded
gravel-sand-siltmixtures o
GRAVEL, CLAYEY, poorly graded
gravel-sand-clay mixture.
SAND, well gtaded, g~avelly
sands, little or no fines.
SAND, poorly graded, gravelly
sands, little or no finss.
SAND, SILTY, poorly graded
sand-silt mixtures,
SAND, CLAYEY, poorly graded
sand-clay mixtures •
SILT, INORGANIC, silt and fine
sand, sandy silt or clayey-
silt-sand mixtures with slight
plastici t y.
CLAY, INORGANIC, clays of low to
medium plasticity, gravelly
clays, sandy clays, silty clays,
lean clays.
SILT, ORGANIC, silts and o~
ganic silt-clays of low
plasticity.
SILT, INORGANIC, silts micaceous
or dictomaceous fine sandy or
silty soils, elastic silts.
CLAY, INORGANIC, clays of med~
ium to hi~h p14sticity, fat
clays.
CLAY, ORGANIC, clays of medium
to high plasticity.
PEAT, other highly organic
swamp soils.
SOIL AND MATERIAL TESTING LABORATORY
CF' NORTH CCIJNTY, INC.
. t
PRELIMINARY SOIL INVESTIGATION
PROPOSED CARLSBAD TRACT 76-1
CHESTNUT GARDEN~ SUBDIVISION
CARLSBAD, CALIFORNIA FOR
MR. M. S. HUMPHREYS
CARLSBAD, CALIFORNIA
JOB NO. 76-50
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