HomeMy WebLinkAboutCT 73-39; Spinnaker Hills; Soils Report; 1975-01-07INSPECTION TESTING RESEARCH DEVELOPMENT
6280 Riverdale St. San Diego,, California 92120 Phone 280-4321
- - - 3 -4704
January 7 , 1975
Standard Pacific of San Diego 7670 Clairemont Mesa Boulevard San Diego, California 92111
Attention: Mr. Robert Allan
SCT 312503 Report No, 4 !
SUBJECT : Supplemental Investigation of P.lluvium Adjacent to Laqoon Lane, Proposed Spinnaker Hill Subdivision, Carlsbad, Cal- ifornia.
Gentlemen:
In accordance with your request and our proposal of Novelrber 22, 1974,
we have performed a supplemental soil investigation of the alluvium to
the rear of Lot NOS. 56 through 60 and within Lot Nos. 79 through 81
of the subject subdivision. Presented herein is a report of our find-
ings and recommendations which should be considered as an integral
part of our "Preliminary Soill Investigation" for the site and dated
September 25, 1913,
Scope
The scope of our work consisted of the following:
1. Extending three borings to depths of from 24 to 34 feet be-
low grade.
2.,. Laboratory tests to determine the in-situ density and con-
solidation characteristics.
3. Fngineering analysis of the consolidation characteristics.
PP'
January 7, 1975 Page Two
Findings
presented on Plate No. 1 of this report. are the approximate boring lo-
cations. The logs of the individual borings are presented on Plate
Nos. 2 through 5. The sample driving energy as well as the dry den-
sity and.moisture content of selected samples are also presented on.
the boring logs. The laboratory consolidation test results are pre-
sented on Plate No. 6.
The borings indicate that the alluvial and/or colluvial soils vary
from 19 to 34 feet thick in the areas investigated. ' It was further
found that the density of the soils increased markedly below a depth
of 5 .to 6 feet. 'Groundwater was encountered only in Boring No. 2
and at a depth of 30.5 feet below grade. In general, the upper 5
feet of soil in each of the three borings was found to be very dry
dnd loose.
Consolidation tests performed on samples below a depth of 5 feet
-- showed low to moderate conso4idation and little change due to sat-
uration. -
Recornendations
Based on the above findings, it is reconmended that the upper 5 feet
.~ of alluvial soils within area intended to receive additional fill
and/or structural loads be removed ad reconpacted to at least 90
percent of maximum dsnsity. The recompaction should extend to at 4- least 5 feet beyond the toe of proposed fill slopes. B'
SCT 312503 January I , 1975 Page Three
-
It has been estimated that within the.lots affected; i.e., Lot Nos.
~ 53 through 60, 78 through 81, and rear of Lot Nos. 136 and 137, ap-
proximately 16,000 to 21,000 cy of alluvium will require recompaction.
It is further recommended that prior to the subrnission.of a final
grading plan, the approximate lateral extent of the material to be
recompacted should be indicated on the plan to assist the grading
~~~ contractor. Please contact .the undersigned when this information
-
is desired.
-
If you have any questions after reviewing our report, please.do not
hesitate to contact this office. -
This opportunity to be of service is sincerely appreciated.
Respectfully submitted,
SOUTHERN CALIFORN?A TESTING LAB., INC.
-
- TVL/nrg cc: (3) Submitted I
(3) Rick Engineering,
(1) 3mL, Escondido
- Attn t Jerry Hofrnaister
BORING NUMBER 1
DESCRIPTION
Medium Brown, Dry, Very Loose SILTY SAND (Alluvium)
Light Orange-Brown , Loose
Dark Brownr Moist , Dense , CLAYEY
SAND
Orange-Brown I Medium Dense
Gray, Wet , Medium Dense SANDY
CLAY (Weathered Formational?)
.""" """"" Gray-Brownr%oiSt I Hardr SILTY
CLAY
(Eocene Santiago Formation).
. .
- E
34
30
16
20
44
Y -
106 .O
119 -9
111.6
119 6
M -
4.2
9.5
.9 ,6
12.4
SOUTHERN CALIFORNIA Proposed Spinnaker Hill Subdivision Carlsbadr California TESTINO LABORATORY, INC. -
8280 RIVEROALE STREET 8AN DIEQO, CALIFORNIA 02120 ..
- BY DATE DH 12-5-14
No' 312503 PLATE NO. 2 BORING LOG
CLAS s
30
BORING NUKBBER 2
DESCRIPTION E
Medium Brown, Dry, Loose to Medium
Dense, SILTY SAND
(Alluvium)
Gray-Brown, Medium Dense to Dense 38
."""""""_
Orange-Brown , Humid , Veclium Dense
to Dense, SILTY CLAYEY SAND
36
14
20
Moist to Wet I 20
',
16
FOR IL?GF%ND SEE PLATE NO. 5
- Y
116.2
121.4
107.6
116.4
119.2
115.0
n -
6.0
6.7
*. 7.4
9.8
13.1
13.5
- @ SOUTHERN CALIFORNIA "
,.
TESTING LABORATORY, INC. Proposed Spimakgr Hill Subdivision
0280 RIVERDALE STREET SAN DIEQO, CALIFORNIA 92120
Carlabad, California -
BY
..
-
PLATE NO. 3 312503
DATE 12-5-74 DH BORING LOG JOB NO.
,. BORING NUMBER 2 (Cont'dl
CLMS DESCRIPTION
Gray-Brown, Saturated, (Hole
Caving-Free Water)
FOR LFGFEID SEF PLATE 110. 5
E -
13
- Y
108.1
- M
20.7
SOUTHERN CALIFORNIA
TESTING LABORATORY, INC. . Proposed Spinnaker Hill Subdivision -
0280 RIVERDALE STREET 8AN DIEQO, CALIFORNIA 92120
Carlsbad, California
- BY DATE DH
PLATE NO. 4 No' 312503
12-5-74
BORING LOG -~
25 f
BORING NUMBER 3
DESCRIPTION - E
Medium Brown, Dry, Very Loose to Loose, SILTY SAND
(Alluvium)
""""""""
Yellow-Brown to Orange-Brown, Humid,
Medium Dense to Dense, SILTY CLAYEY
SAND
68
34
Gray Mottled Dark Brown, Hoist, Stiff,
SILTY CLAY (Weathered Formational) 26
Light Gray, Moist, Dense, SFl?DY SILT
(E6Cene Sanqiago Formation)
_____~~ ~~ ~~~~~~~
c
Y -
116.0
114.6
111.5
LEGFND: F: Sampler Penetration Pesistance (Ft. Kips/Ft.)
Y: Natural Dry Density (pcf )
M: Natural f'oisture Content (8 of Y)
M -
8.7
7.7
16.5
SOUTHERN CALIFORNIA I' TESTING LABORATORY, INC. . Proposed Spinnaker Vi11 Subdivision
wao RIVERDALE STREET Carlsbad, California SAN DIEQO, CALIFORNIA 82120
BY DH DATE
BORING LOG 12-5-14
No' 312503 PLA'IT MO. 5 , I I
CONSOLIDATION TEST RESULTS
Sample No. Load, Ksf
B1 @ 5' 1.44
B1 @ 25' 2.86
B2 @ 6' 2.86
B2 @ 11' : 3.58
~2 @ i5' 4.30
B2 @ 24' 5.00
83 @ 10' 1.44
% Consolidation
2.61
2.50
2.21
2.44 *
2.66
5.28
2.42
After Saturation
% Consolidation
3.93
0.73
2.51
2.59
3.41
5.38
2.01
SCT 312503 PLATE NO. 6
,- UNIFIED SOIL CLASSIFICATION CHART
SOIL DESCRIPTION GROUP SYMBOL
1. COARSE GRAINED, More than half of material is larser than No. 200 sieve size.
GRAVELS CLEAN GRAVELS Gw
More than half of coarse fraction is
larger than No. 4 GP
sieve size but ~~ smaller than 3". GRAVELS WITH FINES GM (Appreciable amount .
of fines) GC
- SANDS CLEAN SANDS sw More than half of ' coarse fraction is SP smaller than NO. 4
sieve size. SANDS WITH FINES SM
of fines) (Appreciable amount sc
11. FINE half than
GRAINED, More 'than of material is smaller No. 200 sieve size.
SILTS AND CLAYS
Liquid Limit , less than 50
SILTS AND CLAYS
ML
CL
OL
Mn
Liquid Limit ai greater than 50 OH
HIGHLY ORGANIC SOILS PT
TYPICAL NAMES
Well graded gravels, gravel- sand mixtures, little or no fines. Poorly graded gravels, gravel sand mixtures, little or no
Silty gravels, poorly graded fines .
gravel-sand-silt mixtures. Clayey gravels, poorly graded gravel-sand, clay mixtures.
Well graded sand, gravelly sands, little or no fines. Poor'ly graded sands,gravelly sands, little or no fines.
Silty sands, poorly graded sand and silt mixtures. Clayey sands, poorly graded sand and clay mixtures.
Inorganic silts and very
silt or clayey-silt-sand fine sands, rock flour, sandy
mixtures with slight plast- icity Inorganic clays of low to medium plasticity,gravelly clays, sandy clays,silty clays, lean clays. Organic silts and organic silty clays of law plasticity Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts.
plasticity, fat clays. Inorganic clays of high
to high plasticity. organic clays of medium
Peat and other highly organic soils.
SOUTHERN CALIFORNIA TESTING LABORATORY