HomeMy WebLinkAboutCT 72-21; Tanglewood; Soils Reports; 1974-02-28_I lo ,j -5. bo-77 (, 1
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Lockwood-Singh ti Associates
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A CORPORATION .~
Consulting Foundallon Engineers and Geoioglsls
9977 Jefferson Bouievard ' Culver Cily, California 90230
Telephone: (213) 870-7335
Proj. Ref. 234-42
February 28, 1974
Larwin Company
Beverly Hills, California 90212 9109 Wilshire Boulevard
SUBJECT: COMPACTION TEST RESULTS ABOVE ELEVATION 100, TFNATIVELY IWED TANGLEWOOD TRACT 7 2- 21 CARLSBAD, CALIFORNIA
Gentlemen:
&2'
This report presents the results of field density and labora-
tory testing of fill soils above elevation 100 at the subject
site. Testing was confined to two relatively flat previously graded areas within Tanglewood Tract 72-21 which at this time is devoid of structures. For the. purposes of this report these areas are herein designated-as Parcel I-&.Parcel
11. Parcel I is bog.&cd. on..tl!e-,north.~b~larron Road and^ is
. ;e~arat.ed.;rom dwellings on the east b a aved access road-. arp1 I1 1s bounded on the west by i$k?kjTEa~ Iilglniay
andion the east by a natural west facing slope.
Teiting of the fill was acco~rpolishd on Fcbrua~y 27, 1974 uuhg a caterpillar tractor-loader which excavatd a total of
made of each test pit followd by taking field density tests
1s test pits within parcels I & 11. A visual inspection ws
of the fill soils. No oversize boulders or cemented deleterious
materials were observed in the test pits. Field density tests were taken at frequent intervals above elevation 100 to ascertain the compaction characteristics of the fill soils.
All in situ density testing was accompolished in accordance with ASlN D-1556-64. Laboratory determination of the maximum
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Proj. Ref. 234-42
Larwin -2- February 28, 1974
with ASTMD 1557-66T. The data for field density tests density of the fill soils was accompolished in accordance
and laboratory testing is presented in the attached Tables I & 11. Approximate location of test pits and compaction tcsts are indicate3 on Plate A. Generall.y, the compaction charac-
teristics of the fill soils were satisfactory i.e. percent
conlpaction was 90$ or greater, except for localized portions which may have to be recompactcd when actual building areas
have been cstablishod. Surface tests within top 6 inches were
fraction within the upper .1 foot of the soil wherein an increase
in gcncral substardard which is probably due to the clayey
in volume may have occurred when in contact with water. These areas may have to be re-compacted prior to construction.
Minor surficial erosion of Parcel I1 was noted which has been caused by runoff from the adjacent natural slope onto the
pad area, No significant erosion was noted within Parcel I.
Allowable bearing values may be assumed at 2000 psf for
foundations placed a minimum of 18 inches into either compacted fill soils or natural ground. Attempts should be made got to place foundations astride natural ground/fill
interface.,
Surface fill soils at the site generally exhibited low swelling potential, howver, due to the expansive charac-
teristics of topsoil which was mixed with the fill soils during grading, local expansive conditions may underlie
proposed floor slabs. Although expansive soils are not anti-
cipated to be vely prevalent, inspections should be made prior to construction.
" Soil =e - The soils encountered in the fill above elevation
100 in b-th the parcels were prcdoninently sandy, clayey silts. Plate B shows the moisture density curve of the fill soil. The plate also shows, in dotted lines, approximate moisture density Furves of some of the other fill soils below elevation
- 100. The latter data is based on work of others, dated June 5, 1973. lVe recognize approximate 6-7 different soil
types in the fill.
Respectfully submitted,
LOCNVCOD-SIKH tj ASSOCIATES
Awtar Singh CE 17727
AS:m1
farley /byJz . Tucker
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Test No.
1
2
3
4
5
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..
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18
19
20
21
22
" 23 24
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Proj. Ref. 234-42
Larwin -3- February 28, 1974
" TABLE I
SJbMRY OF FIELD DENSITY DETF-RMINATIONS
Date Test
Location - Test Soil Dry Elev. % Density (% dry wt.] tion IKTE Moisture Compac-
In Situ In Situ Rel.
-
108
105
104
102
102
110
108
101
106
103
100
103
106
102
102
114
101 103 101
105 101
107
102
110
109 14.8
112
111
11.4
15.8 109 18.3
118
111
12.8
12.7
122 15.2
109 15.3
114 14.7
100 22.5
109 14.5
114. 15.3
105
99
15.0
17.5
99 14.9
104 12.0
114 10.8
109
109 13.5
9.5
97 16.6
114 13.8
117 8.4 109
123
14.2
6.2
90
92
91
90
97
91
100
90
94
82" Surface Test
90
94
86" Surface Test
82" Surface Test
82" Surface Test
86" Surface Test
94
90
90
80" Surface Test
94
.,
96 90
101
* Denotes substandard compaction.
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Proj. REf. 234-42 Larwin -4- February 28, 1974
TABLE 'I I "
SUMVARY OF LABORATORY'DENSITY DETERMINATIONS
Soil m. Description
Maximum Dry* Moisture Content Density (pcf) (%' dry wt.)
optimum
A Buff, very fine- 121.5 10.0 - grained sandy silt ,
(slightly clas
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"Compaction standard ASTM D-1557 (5 layers)
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60
JOE EA% IJIIIWIN-CARI~~I~W
JOE NO. 234-42
DATE February 28, 1974
SOIL U)CAI'ION
SOIL TYPE
Test No. I I i i
Wt. wet soil & mold I
Wt. mold ! i !
Wt. wet soil I
Factor ._i.-_l.__ ! !
. .~ "" _.+-..-" ' "I ....... i i -. ." . ~- ___l .
- .- ... _" ... ." .... I I i
"- -- - I
.............
'- -' '.'i --. 'I-"
wet-densitY." ..... " -
. " ....... "" .... 1". _"
Wt. wet soil tare 1 I
Wt. - dry ~~ .~ soil ~ & tare"1~". . i I
Wt. tare 'I I
-+-
Wt. moisture
Wt. dry soil i
Moisture content, % 1
Dry density I i .
". -
. I
"" .. ....... .- ~
_"
"" ......... ... - ... - . i
....... I. "" . "
. "" "" . . I "" I
~" .__- ' .- -
- " " - "
Max. Dry Density : lb/ft3
Opt. Moisture : % of dry wt.
GEOTECHNICAL INVESTIGATION FOR PROPOSED
36 MT SUBDIVISION
WINTERGREEN DRIVE VISTA DE LA VALLE
CARLSBAD, CALIFORNIA
PREPARED FOR:
Wesco Development
Torrance, California 90505
2601 Airport Drive, #250
PREPARED BY: Ketchum Engineering, Inc.
7818 Quebrada Circle
Carlsbad, California 92009
KETCHUM ENGINEERING, INC.