HomeMy WebLinkAboutCDP 2019-0002; SMITH (HILLSIDE DR) RESIDENCE; FINAL SOILS REPORT; 2024-09-10
10 September 2024
Mr. Jessie Smith Job No. 18-11842
447 Bougher Road
San Marcos, CA 92068
Subject: Final As-Graded Soils Report
Smith Residence
4246 Hillside Drive
Carlsbad, California
Dear Mr. Smith:
Per your request and as required by the City of Carlsbad, Geotechnical Exploration,
Inc. hereby presents this final as-graded soil report for the work performed at the
site. See Figure No. I, Vicinity Map, for site location. The work was performed
between June 22, 2021, and March 11, 2022. Our firm previously performed a
geotechnical investigation of the site, the results of which were presented in our
Report of Preliminary Geotechnical Investigation dated April 9, 2018, followed by an
Update Report of Preliminary Geotechnical Investigation dated November 13, 2020.
We also issued the following documents for this project:
Response to City of Carlsbad Third-Party Reviewer (First) dated November 13,
2020;
Response to City of Carlsbad Third-Party Reviewer (Second) dated April 13,
2021.
Report of Rough Grading Observations and Soil Testing, dated April 15, 2022.
The earthwork reported herein was performed in accordance with the
recommendations presented in our geotechnical reports.
Smith Residence Job No. 18-11842
Carlsbad, California Page 2
FIELD OBSERVATIONS
As previously mentioned, a rough grading report was issued on April 15, 2022. The
following is a brief summary of the work performed. For more detailed information,
refer to our report.
Our representative observed the grading and backfilling of the old canyon area
located approximately near the center of the lot. A storm drain culvert running
perpendicular in the center of the lot was observed, along with the grading of the
residential building and garage pads. The house and garage were founded on suitable
recompacted fill soils. Refer to Figure No. II, Plot Plan, for test locations.
The driveway subgrade and finished grade were tested for compaction including the
backfill placement for the north driveway retaining wall and east garage retaining
wall. Backfill soils placed around the perimeter of the north and south manhole boxes
were observed and tested for recompaction. No additional soil work has been
performed or observed since issuing our April 15, 2022, report.
SOIL TESTING
Representative soil samples were collected during the grading to determine
laboratory maximum dry density of the soils per ASTM D1557-12e1. Field density
tests were performed at approximate locations shown on Figure No. II, Plot Plan in
accordance with ASTM D6938-17a. The complete list of field density tests results is
shown on Table A of Figure Nos. IIIa-b, and laboratory soil compaction test results
are shown on Table B of Figure No. IIIc.
Smith Residence Job No. 18-11842
Carlsbad, California Page 3
Equipment used for the earthwork compaction consisted of a Mini-excavator and a
Bobcat with rubber tires. A water hose was used, when needed, to increase the soil
moisture. Field density tests yielded a relative compaction of at least 90 percent of
maximum dry density at the tested locations. Density tests were performed with a
nuclear gauge testing apparatus in accordance with ASTM D6938-17a. The maximum
dry density of the soils was determined per ASTM D1557-12e1. The on-site soil
material used for the earthwork consisted of light and dark brown silty sand, and
reddish-brown silty sand. The imported soils consisted of brown and dark brown
clayey sand. The on-site soils were determined to have low expansion with an
expansion index (E.I.) of less than 50. The imported soils were visually classified to
have low expansion characteristics per ASTM D4829.
Proper finish drainage for the site was to be implemented by the general contractor
prior to completing construction.
SITE SUITABILITY AND COMPLIANCE
The observed and tested areas of the grading operation including the underlying
dense formational soils are, in our professional opinion, suitable for their intended
use of supporting the recompacted fills, structure foundations, and new exterior
improvements.
We certify that the soil engineering aspects of grading are in general compliance with
the approved soils report and the grading plans.
Smith Residence Job No. 18-11842
Carlsbad, California Page 4
LIMITATIONS
The findings and opinions presented herein have been made in accordance with
currently accepted principles and practice in the field of geotechnical engineering in
the City of Carlsbad in the County of San Diego. No warranty, either expressed or
implied, is made.
All statements in this report are applicable only for the grading operation observed
and tested by our firm. The firm Geotechnical Exploration, Inc. shall not be held
responsible for fill soils placed without our observations and testing at any other time,
or subsequent changes to the site by others, which directly or indirectly cause poor
surface or subsurface drainage, water erosion, and/or alteration of the strength of
the compacted fill soils.
It is not within the scope of our services to provide quality control oversight for
surface or subsurface drainage construction or retaining wall sealing and base of wall
drain construction. It is the responsibility of the contractor to verify proper wall
sealing, geofabric installation, protection board installation (if needed), drain depth
below interior floor or yard surfaces; pipe percent slope to the outlet, etc.
Any future earthwork should be observed by our firm. In the event that any changes
in the nature, design, or location of buildings or improvements are planned, the
conclusions and recommendations contained in this report should not be considered
valid unless the changes are reviewed and the conclusions of this report modified or
verified in writing.
Smith Residence Job No. 18-11842
Carlsbad, California Page 5
This opportunity to be of service is sincerely appreciated. If you have any questions
regarding this letter, please contact our office. Reference to our Job No. 18-11842
will help expedite a response to your inquiry.
Respectfully submitted,
GEOTECHNICAL EXPLORATION, INC.
_______________________________ ______________________________
Jaime A. Cerros, P.E. Richard A. Cerros. P.E.
R.C.E. 34422/G.E. 2007 R.C.E. 94223
Senior Geotechnical Engineer
Smith Residence
4246 Hillside Drive
Carlsbad, CA.
Figure No. I
Job No. 18-11842
SITE
VICINITY MAP
Thomas Bros. Guide San Diego County, pg 1106-G6
59 Approximate Location
of Field Density Test
1
3 4
2
5
7
6
8
9
15
1314
16
12
17
2824
27
25
26
23 21
20
19
11
22
18
10
29
30
31
32
33
35
34
36
3739
38
40
41
43
42
4445
47
46
48
49
51
50
52
5458
55
59
56
57
53
Old Paralic Deposits, unit 2-4
Artificial Fill
Qop
Qaf
Qaf
2-4
Qop2-4
Qaf
Qop2-4
18-11842-P3.ai
Smith Residence
4246 Hillside Drive
Carlsbad, CA.
Figure No. II
Job No. 18-11842
PLOT PLAN AND
SITE SPECIFIC
GEOLOGIC MAP
Legend
NOTE: This Plot Plan is not to be used for legal
purposes. Locations and dimensions are approximate.
Actual property dimensions and locations of utilities
may be obtained from the Approved Building Plans
or the “As-Built” Grading Plans.
( September 2024 )
GRAPHIC SCALE
( Feet )
Geologic Legend
Approximate Limits of
Observed Grading
H
I
L
L
S
I
D
E
D
R
I
V
E
REFERENCE: This Plot Plan was prepared from an existing LANDSCAPE
CONSTRUCTION PLAN by GREG HEBERT LANDSCAPE ARCHITECT
dated 11/7/19 and from on-site field reconnaissance performed by GEI.
April 2022
TABLE A
Approximate Water Dry Degree of
Test Elevation Content Density Compaction Compaction
No. Date of Test Test Location (Feet) (%) (pcf) (%) Curve No. Remarks
1 6/22/21 CANYON AREA 93.5 9.8 117.3 91 2 Onsite
2 6/22/21 CANYON AREA 93.5 8.9 118.0 91 2 Onsite
3 6/22/21 CANYON AREA 93.5 10.0 119.2 92 2 Onsite
4 6/22/21 CANYON AREA 93.5 9.0 116.9 90 2 Onsite
5 6/22/21 CANYON AREA 93.5 8.6 117.7 91 2 Onsite
6 6/23/21 CANYON AREA 95 9.4 110.5 85 2 Onsite
7 6/23/21 CANYON AREA 95 10.4 111.6 91 1 Onsite
8 6/23/21 CANYON AREA 95 11.0 110.9 90 1 Onsite
9 6/23/21 CANYON AREA 95 10.1 112.0 91 1 Onsite
10 6/24/21 CANYON AREA 95 10.7 110.8 90 1 Onsite
11 6/24/21 CANYON AREA 95 11.3 111.4 90 1 Onsite
12 6/29/21 CANYON AREA 96 9.9 111.9 91 1 Onsite
13 6/29/21 CANYON AREA 96 10.4 112.8 92 1 Onsite
14 6/29/21 CANYON AREA 96 9.5 112.3 91 1 Onsite
15 6/28/21 CANYON AREA 97 9.6 121.4 94 2 Onsite
16 6/28/21 CANYON AREA 97 9.9 122.2 95 2 Onsite
17 6/28/21 CANYON AREA 97 10.4 121.7 94 2 Onsite
18 7/7/21 GRADING - BLDG PAD 107.5 10.2 108.0 90 3 Onsite
19 7/7/21 GRADING - BLDG PAD 107.5 12.8 114.4 93 1 Onsite
20 7/9/21 GRADING - BLDG PAD 104 10.2 111.6 91 1 Onsite
21 7/9/21 GRADING - DRIVE 105 9.3 118.1 91 2 Onsite
22 7/18/21 GRADING - DRIVE 95 7.2 113.6 92 1 Onsite
23 7/18/21 ST DRAIN TRENCH BFILL 96 8.9 111.5 91 1 Onsite
24 7/19/21 ST DRAIN TRENCH BFILL 96.5 11.2 111.9 91 1 Onsite
25 7/19/21 GRADING - DRIVE 97 7.2 116.9 90 2 Onsite
26 8/12/21 GRADING UPPER PAD BLDG 109.5 7.6 119.6 91 4 Import
27 8/12/21 GRADING UPPER PAD BLDG 109.5 8.3 120.1 91 4 Import
28 8/12/21 GRADING UPPER PAD BLDG 109.5 7.2 119.4 90 4 Import
Job No. 18-11842
Figure No. IIIa
SUMMARY OF FIELD DENSITY TEST RESULTS (ASTM D1556 and/or ASTM D6938)
Notes: 1) Curve number refers to Table B
2) FSG denotes finish subgrade elevation
3) FBG denotes finish base grade elevation
4) FPG denotes finish pavement grade
TABLE A
Approximate Water Dry Degree of
Test Elevation Content Density Compaction Compaction
No. Date of Test Test Location (Feet) (%) (pcf) (%) Curve No. Remarks
SUMMARY OF FIELD DENSITY TEST RESULTS (ASTM D1556 and/or ASTM D6938)
29 8/31/21 S. MANHOLE 96.5 10.6 113.8 92 1 Onsite
30 8/31/21 GARAGE PAD 99.5 9.8 113.3 92 1 Onsite
31 8/31/21 N. DRIVEWAY 100 11.2 112.2 91 1 Onsite
32 8/31/21 N. DRAINAGE BOX 99 9.4 113.5 92 1 Onsite
33 9/3/21 N. DRIVEWAY 102 14.0 102.0 91 5 Import
34 9/3/21 N. DRIVEWAY 104 13.7 103.1 92 5 Import
35 9/9/21 N. DRIVEWAY 106 12.9 112.2 92 6 Import
36 9/10/21 N. DRAINAGE BOX 102 13.0 111.8 92 6 Import
37 9/10/21 GARAGE 102 12.4 112.5 92 6 Import
38 9/10/21 GARAGE 102 13.2 112.0 92 6 Import
39 9/13/21 GARAGE 104 13.9 112.2 92 6 Import
40 9/13/21 GARAGE 104 14.2 112.0 92 6 Import
41 9/20/21 DRIVEWAY 108 13.7 111.6 91 6 Import
42 9/22/21 DRIVEWAY 110 11.2 112.5 91 1 Onsite
43 9/28/21 DRIVEWAY 104 10.7 113.1 92 1 Onsite
44 9/28/21 DRIVEWAY 104 11.0 112.7 91 1 Onsite
45 11/19/21 DRIVEWAY AREA WALL BACKFILL 101.5 12.9 111.8 92 6 Onsite
46 11/19/21 DRIVEWAY AREA WALL BACKFILL 103.5 13.7 112.6 92 6 Onsite
47 11/24/21 DRIVEWAY AREA WALL BACKFILL 105 12.0 110.9 91 6 Onsite
48 1/20/22 HOUSE/GARAGE E. RETAINING WALL 106 13.1 110.4 90 6 Onsite
49 1/20/22 HOUSE/GARAGE E. RETAINING WALL 106 11.8 110.0 90 6 Onsite
50 1/20/22 HOUSE/GARAGE E. RETAINING WALL 108 12.4 111.2 91 6 Onsite
51 1/20/22 HOUSE/GARAGE E. RETAINING WALL 108 11.5 112.0 92 6 Onsite
52 1/21/22 HOUSE/GARAGE E. RETAINING WALL 108 12.1 110.3 90 6 Import
53 1/21/22 HOUSE/GARAGE E. RETAINING WALL 108 12.6 110.7 91 6 Import
54 1/21/22 HOUSE/GARAGE E. RETAINING WALL 110 11.9 113.0 93 6 Import
55 1/21/22 HOUSE/GARAGE E. RETAINING WALL 110 12.8 112.3 92 6 Import
56 3/11/22 HOUSE PAD FINISH 110.6 FSG 11.0 111.6 91 6 Import
Job No. 18-11842
Figure No. IIIb
Notes: 1) Curve number refers to Table B
2) FSG denotes finish subgrade elevation
3) FBG denotes finish base grade elevation
4) FPG denotes finish pavement grade
TABLE A
Approximate Water Dry Degree of
Test Elevation Content Density Compaction Compaction
No. Date of Test Test Location (Feet) (%) (pcf) (%) Curve No. Remarks
SUMMARY OF FIELD DENSITY TEST RESULTS (ASTM D1556 and/or ASTM D6938)
57 3/11/22 HOUSE PAD FINISH 110.6 FSG 10.7 110.9 91 6 Import
58 3/11/22 GARAGE PAD FINISH 108 FSG 11.2 111.5 91 6 Import
59 3/11/22 GARAGE PAD FINISH 10.5 112.9 92 6 Import
Job No. 18-11842
Figure No. IIIc
Notes: 1) Curve number refers to Table B
2) FSG denotes finish subgrade elevation
3) FBG denotes finish base grade elevation
4) FPG denotes finish pavement grade
Job No. 18-11842
Figure No. IIId
TABLE B
LABORATORY COMPACTION TEST RESULTS (ASTM D1557)
Compaction Maximum Optimum
Test Source of Dry Density Water Content
Curve No. Description of Material Material (pcf) %
C-1 RED-BROWN SILTY SAND (SM) 123.2 11.5
C-2 DARK BROWN SILTY SAND (SM) 129.3 9.3
C-3 LIGHT BROWN SILTY SAND (SM) 119.7 11.3
C-4 DARK BROWN CLAYEY SAND (SC) Import 132.0 8.0
C-5 BROWN SANDY CLAY (CL) Import 112.2 13.5
C-6 BROWN ANDY CLAY/CLAYEY SAND (CL/SC) Import 122.1 12.2