HomeMy WebLinkAboutCT 97-02; RANCHO CARILLO VILLAGES A-D; ADDENDUM REPORT; 1998-10-09GEOCON
INCORPORATED
Project No. 05845-12-16
October 9, 1998
Continental Ranch Inc.
12230 El Camino Real, Suite 300
San Diego, California 92130
Attention: Mr. Dave Lother
Subject: VILLAGE C
RANCHO CARRILLO
CARLSBAD, CALIFORNIA
ADDENDUM REPORT
UNDERCUTTING LOT NOS
GEOTECHNICAL CONSULTANTS
20 THROUGH 23, 95, 96, 108, AND 109
(401W)
Reference: Final Report of Testing and Observation Services During Site Grading, Village C,
Rancho Carrillo, Prepared by Geocon Incorporated, dated September 9,1998.
Gentlemen:
This report has been prepared as an addendum to the above referenced report to present the results of
additional grading within the project and subsequent modifications to foundation recommendations.
The additional grading occurred between September 23 and October 5, 1998, and was performed to
replace highly expansive soils exposed at-grade with select soils. Grading included undercutting Lot
Nos. 20-23, 96, 108, and 109, plus the northwest corner of Lot 95. These lots were undercut a
minimum of 3 feet in the removal area and the resulting excavations were backfihled with select soils,
with a "low" expansive potential. The undercut was limited to approximately 5 feet from the street
right-of-way and 2 feet from the adjacent property boundaries.
During the grading operation, compaction procedures were observed and in-place density tests were
performed to evaluate the relative compaction of the fill material. The in-place density tests were
performed in general conformance with ASTM Test Method D-2922-81. The results of the in-place
dry density and moisture content tests are summarized on Table I. In general, the in-place density
test results indicate that the fill soil has a relative compaction of at least 90 percent at the locations
tested. The approximate locations of the in-place density tests are shown on the Revised As-Graded
Geologic Maps, Figures 1 and 3 (enclosed map pocket). It should be noted that since the grading of
Village C was performed in conjunction with grading of Village D, the field density test numbers are
not in sequential order. Tables 4.2, and II through VI have been revised to reflect the current as-
graded conditions and are enclosed herein.
This report is an addendum to the referenced report of grading. All other recommendations of that
report remain valid and applicable to the proposed project.
6960 Flanders Drive U San Diego, California 92121-2974 • Telephone (619) 558-6900, I Fax (619) 558-6159
If you have any questions regarding this report addendum, or if we may be of further service please
contact the undersigned at your convenience.
Very truly yours,
I
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AS:DFL:dmc
$Ai adr
CEG 1778
(6/del) Addressee
(2/del) Continental Ranch Inc., Job Site
Attention: Mr. Clegg Atherton
(3/del) Continental Ranch, Inc. Jobsite
Attention: Mr. Mike Lombardi
ect No. 05845-12-16 - 2 - October 9, 1998
Project No. 05845-12-16 (C) TABLE I
FIELD DENSITY TEST RESULTS
Elev. Plus Max. Opt. Field Field Field Req'd
or 3/4" Dry Moist. Dry Moist. Rel. Rel. Test Depth Curve Rock Dens. Cont. Dens. Cont. Comp. Comp. No. Date Test Location (ft) No. (%) (pcf) (%) (pcf) (%) (%) (%)
800 09/30/98 VILLAGE C LOT 96 436 17 0 112.2 15.5 99.2 20.8 88 90
800A 10/05/98 VILLAGE C LOT 96 436 17 0 112.2 15.5 101.9 18.5 91 90
801 09/30/98 VILLAGE C LOT 108 446 20 0 114.3 14.9 105.4 16.7 92 90
802 09/30/98 VILLAGE C LOT 109, 447 20 0 114.3 14.9 104.7 17.1 92 90
806 10/01/98 VILLAGE C LOT 22 435 20 0 114.3 14.9 104.7 18.8 92 90
807 10/01/98 VILLAGE C LOT 23 436 20 0 114.3 14.9 103.6 17.9 91 90
810 10/01/98 VILLAGE C LOT 20 431 20 0 114.3 14.9 107.1 15.6 94 90
811 10/01/98 VILLAGE C LOT 21 432 20 0 114.3 14.9 104.3 16.2 91 90
FG 803 09/30/98 VILLAGE C LOT 108 448 20 0 114.3 14.9 106.5 15.7 93 90
FG 804 09/30/98 VILLAGE C LOT 109 448 20 0 114.3 14.9 107.0 15.2 94 90
FG 805 09/30/98 VILLAGE C LOT 95 438 17 0 112.2 15.5 101.8 18.4 91 90
FG 808 10/01/98 VILLAGE C LOT 22 437 20 0 114.3 14.9 105.4 17.5 92 90
FG 809 10/01/98 VILLAGE C LOT 23 437 20 0 114.3 14.9 105.9 17.1 93 90
FG 812 10/01/98 VILLAGE C LOT 20 433 20 0 114.3 14.9 106.5 15.9 93 90
FG 813 10/01/98 VILLAGE C LOT 21 433 20 0 '114.3 14.9 106.2 16.8 93 90
Note: See last page of table for explanation of coded terms
AD - Area Drain
B - Base Test
CC - Curb & Gutter
CW - Crib Wall
DW - Driveway
FG - Finish Grade
IT - Irrigation Trench
JT - Joint Trench
MT - Moisture Test
RW - Retaining Wall
SD - Storm Drain
SC - Subgrade
SL - Sewer Lateral
SM - Sewer Main
ST - Slope Test
SW - Sidewalk
SZ - Slope Zone
UT - Utility Trench
WB - Wall Backfill
WL - Water Lateral
WM - Water Main
- CURVE NO.
Project No. 05845-12-16 (C)
EXPLANATION OF CODED TERMS
- TEST SUFFIX
A, B, C,...: Retest of previous density test failure, following moisture conditioning
and/or recompaction.
R: Fill in area of density test failure was removed and replaced with
properly compacted fill soil.
- PREFIX CODE DESIGNATION FOR TEST NUMBERS
Corresponds to curve numbers listed in Table II, representing the laboratory
maximum dry density/optimum moisture content data for selected fill soil samples
encountered during testing and observation.
- ROCK CORRECTION
For density tests with rock percentage greater than zero, laboratory maximum dry density and optimum
moisture content were adjusted for rock content. For tests with rock content equal to zero, laboratory
maximum dry density and optimum moisture content values listed are then unadjusted values.
- TYPE OF TEST
- SC: Sand Cone Test
NU: Nuclear Density Test
DC: Drive Cylinder Test
- ELEVATION/DEPTH
Test elevations/depths have been rounded to the nearest whole foot.
TABLE 4.2., REVISED
SUMMARY OF RECOMMENDATION FOUNDATION CATEGORY
Lot Numbers * Recommended Foundation Category
1 through 9, 40 through 63, 72, 73, and 78 through 97, 108 and
109 I
10 through 13, 24 through 39, 64 through 71, 74, 75, 98
through 107, and 110 through 115 II
14 through 23, 76 and 77 III
*Lot 13 is designated as open space
TABLE II, REVISED
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY
AND OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D 1557-91
Sample Description Maximum Dry Optimum Moisture
No. Density (pci) Cdntent (% dry wt.)
1 Light brown, Silty CLAY 113.4 14.6
2 Yellow-tan, Silty, fine to medium SAND,
with trace clay 115.0 14.0
3 Light brown to brown, Sandy CLAY, trace
silt 116.4 13.6
4 Green, Silty CLAY, with little fine to
medium sand 115.8 15.7
9 Yellow-brown, Silty CLAY with some fine
to medium SAND 107.1 17.1
12 Green-gray-tan Silty CLAY with trace Sand
and gravel 114.7 16.0
14 Yellow-tan Silty CLAY 105.0 19.8
15 Dark olive-yellow brown clayey fine SAND
116.8 13.3
16 Olive, fine to medium Sandy CLAY, with
little silt 114.2 16.3
17 Light olive-brown, Silty, fine to coarse
SAND 112.2 15.5
19 Olive, fine to medium, Sandy CLAY, with
little silt 112.8 17.2
20 Light olive-brown Silty fine to medium
SAND 114.3 14.9
Project No. 05845-12-16 October 9, 1998
- TABLE II, REVISED (Continued)
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY
AND OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM 0 1557-91
Sample
No. Description Maximum Dry
Density (pci)
Optimum Moisture
Content (% dry wt.)
24 Light olive, Silty, fine to medium SAND 117.4 13.9
25 Light greenish tan Sandy CLAY 112.2 17.0
26 Tan Silty fine SAND 120.0 12.6
27 Yellow-tan Silty fine to medium SAND,
little clay 114.4 15.1
101 Yellow-gray Silty sand with little CLAY 115.6 14.4
TABLE III
SUMMARY OF DIRECT SHEAR TEST RESULTS
Sample
No.
Dry Density
(pci)
Moisture Content
(%)
Unit Cohesion
(psi)
Angle of Shear
Resistance (degrees)
2 103.4 14.8 400 30
3 104.4 13.6 450 16
9 97.2 17.1 345 28
12 104.0 16.0 525 23
16 103.5 16.3 740 23
17 101.2 15.5 290 36
19 101.2 17.2 255 30
27 103.4 15.1 1 280 30
Note: Samples were remolded to 90 percent relative compaction at near optimum moisture content.
Project No. 05845-12-16 October 9, 1998
TABLE IV, REVISED
SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS
Sample
No.
Moisture Content Dry
Density (pci)
Expansion
Index Before Test (%) After Test (%)
2 11.0 23.0 106.1 12
3 10.7 28.5 105.4 107
4 11.7 29.1 104.1 87
17 12.1 26.1 102.4 23
19 14.2 35.8 96.3 62
C-A 12.2 25.0 102.9 - 25
C-B 11.9 26.0 103.7 16
C-C 12.5 28.9 102.9 72
C-D 12.5 26.1 103.0 67
C-E 13.1 123.0 102.3 14
C-F 14.2 29.7 100.5 65
C-G 13.9 24.2 102.2 30
C-H 12.8 25.9 102.6 37
C-I 12.6 30.9 102.0 - 70
C-J 10.5 32.9 108.9 116
C-K 11.5 32.0 103.6 47
C-L 10.1 30.4 109.1 35
C-M 15.9 42.5 91.1 135
C-N 10.8 31.7 109.0 61
C-O 10.5 29.0 108.0 62
C-P 10.0 26.5 109.4 70
C-Q 11.2 37.8 105.3 97
C-R 10.2 26.4 110.0 54
C-S 11.1 26.0 106.0 50
C-T 9.1 27.6 113.2 47
C-U 108.2 28.7 109.1 23
C-V 10.2 24.8 109.5 14
C-W 10.0 26.9 109.6 53
CX 11.0 28.1 105.7 46
C-Y 9.4 30.2 111.2 48
C-Z 10.5 24.1 109.6 21
C-AA 9.8 28.1 110.7 41
C-BB 11.7 25.9 104.0 23
Project No. 05845-12-16 October 9, 1998
TABLE V, REVISED
SUMMARY OF FINISH GRADE EXPANSION INDEX TEST RESULTS FOR EACH LOT
Lot No. Sample No. Expansion Index UBC Classification
I through 4 C-E 14 Very Low
5 through 9 C-G 30 Low
10 through 13 C-F 60 Medium
14 through 19 C-H 37 Low
20 through 23 C-BB 23 Low
24 through 28 C-C 72 Medium
29 through 33 C-N 61 Medium
34 through 40 C-O 62 Medium
46 through 51 C-T 47 Low
41 through 45 C-S 50 Low
52 through 59 C-U '23 Low
60 through 64 C-V 14 Very Low
65 through 71 C-W 53 Medium
72,73 C-Y 48 Low
74 through 77 C-Z 21 Low
78 through 82 C-AA 41 Low
83 through 85 C-X 46 Low
86 through 89 C-K 47 Low
90 through 94 C-L 35 Low
95,96 C-BB 23 Low
97 through 101 C-D 71 Medium
102, 103 C-I 70 Medium
104 through 107 C-P 70 Medium
108 2 109 C-BB 23 Low
110 through 115 C-R 54 Medium
Project No. 05845-12-16 October 9, 1998
TABLE VI, REVISED
SUMMARY OF AS-GRADED BUILDING PAD CONDITIONS
FOR VILLAGE C, RANCHO CARRILLO
Lot
Number
Pad
Condition
Approximate
Depth of
Fill (feet)
Approximate
Maximum Depth
of Fill Differential
Expansion
Index
Foundation
Category
1-2 Cut 0 0 14 I
3-4 Cut 0 0 14 I
5-6 Cut 0 0 30 I
7-8 Cut 0 0 30 I
9-10 Cut 0 0 65 II
11,12 Cut 0 0 65 H
14-15 Fill 25 24 37 III
16-17 Fill 40 24 37 III
18-19 Fill 45 30 37 III
20-21 Fill 43 27 23 III
22-23 Fill 37 21 23 III
24-25 Fill 32 20 72 III
26-27 Fill 18 14 72 II
28-29 Fill/Undercut 8 6 61 II
30-31 Fill 3 2 61 II
32-33 Fill 2 1 61 II
34-35 Fill 3 1 62 II
36-37 Fill 3 0 62 II
38-39 Fill 3 0 62 II
40-41 Cut/Fill 3 2 50 I
42-43 Cut 0 0 50 I
44-45 Cut 0 0 50 I
46-47 Cut/Fill 2 2 47 I
48-49 Cut 0 0 47 I
50-51 Cut 0 0 47 I
52-53 Cut 0 0 23 I
54-55 Cut 0 0 23 I
56-57 Cut 0 0 23 I
58-59 Cut 0 0 23 I
60-61 Cut 0 0 14 I
62-63 Cut 0 0 14 I
64-65 Cut 0 0 1 53 II
Project No. 05845-12-16 October 9, 1998
- TABLE VI, REVISED (Continued)
SUMMARY OF AS-GRADED BUILDING PAD CONDITIONS
FOR VILLAGE C, RANCHO CARRILLO
Lot
Number
Pad
Condition
Approximate
Depth of
Fill (feet)
Approximate
Maximum Depth
of Fill Differential
Expansion
Index
Foundation
Category
66-67 Cut 0 0 53 II
68-69 Cut 0 0 53 H
70-71 Cut 0 0 53 II
72-73 Cut 0 0 48 I
74-75 Undercut/Fill 14 11 21 II
76-77 Fill 26 23 21 III
78-79 Cut/Fill 2 2 41 I
80-81 Cut 0 0 41 I
82-83 Cut 0 0 46 I
84-85 Cut 0 0 46 I
86-87 Cut 0 0 47 I
88-89 Cut 0 0 47 I
90-91 Cut 0 0 35 1
92-93 Cut 0 0 35 I
94-95 Cut/Undercut 3 3 23 I
96-97 Undercut/Fill 8 5 23 I
98-99 Undercut/Fill 8 5 71 II
100-101 Undercut/Fill 10 7 71 II
102-103 Fill 12 9 70 II
104-105 Fill 3 0 70 II
106-107 Fill 3 1 70 II
108-109 Undercut 3 0 23 I
110-111 Fill/Cut 2 2 54 II
112-113 Cut 0 0 54 II
114-115 Cut 0 0 54 II
Project No. 05845-12-16 October 9, 1998