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(877) 215-43211 oneatlas.com
June 4, 2021
Atlas No. 210120N
Report No. I
MS. REBECCA MCDONALD
WALTERS MANAGEMENT
3207 GREYHAWK COURT, SUITE 140
CARLSBAD, CALIFORNIA 92010
Subject: Geotechnical Update Report
Rancho Carrillo Master Association Erosion Study
Carlsbad, California
Dear Ms. McDonald:
Atlas Technical Consultants LLC (formerly SCST) is pleased to submit our updated report
describing the geotechnical investigation performed for the planned slope reconstruction at the
open space area on the north side of El Fuerte Street in Carlsbad, California. This investigation
was conducted as a response to slope erosion that occurred along the slope. We conducted the
geotechnical update report in general conformance with the scope of work presented in our
proposal dated April 21, 2021. Based on the results of our updated investigation, we consider the
planned development feasible from a geotechnical standpoint provided the recommendations of
this report are followed. If you have any questions, please call us at (619) 280-4321.
Respectfully submitted,
Atlas Technical Consultants LLC
llcL1< No. 9884
* Exp. Feb 1 2023 *
OF
Drew McPeak, PG 9884
Project Geologist FESS
"No. 2591t%
LLJ (' Exp. 9/30/2021 cc Cn
' CERTIFIED 1
/ *\'E3INEERING
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EOLOGIS
% OF
Andrew Neuhaus, CEG 259
Chief Geologist
AKN:ER:DJM:ds
Distribution: rmcdonaIdwaItersmanagement.com
Emil Rudolph, GE 2767
Principal Engineer
CONTENTS
EXECUTIVESUMMARY..............................................................................................................I
INTRODUCTION ...................................................................................................................2
1.1 Field Investigation.........................................................................................................2
1.2 Laboratory Testing........................................................................................................2
1.3 Analysis and Report......................................................................................................2
SITE DESCRIPTION .............................................................................................................3
SITE HISTORY......................................................................................................................3
GEOLOGY AND SUBSURFACE CONDITIONS ..................................................................3
CONCLUSIONS AND RECOMMENDATIONS.....................................................................4
RECOMMENDATIONS .........................................................................................................4
6.1 Excavation Conditions ..................................................................................................4
6. 1.1 Temporary Excavation Slopes.........................................................................4
6.1.2 Site Preparation and Grading..........................................................................5
6.1.3 Fill Material ......................................................................................................5
6.1.4 Compacted Fill.................................................................................................6
6.2 Geotechnical Engineering During Construction............................................................6
CLOSURE .............................................................................................................................6
REFERENCES ......................................................................................................................7
FIGURES
Figure 1 Site Vicinity Map
Figure 2 Geotechnical Map
Figure 3 Geologic Cross Section
Figure 4 Stabilization Fill Details
APPENDICES
Appendix I Subsurface Exploration
Appendix II Laboratory Testing
Appendix III Photo Appendix
Atlas No. 210120N
Report No. 1
Page Ii
EXECUTIVE SUMMARY
This report presents the results of the updated geotechnical investigation Atlas Technical
Consultants (Atlas) performed for the subject project. The site is located in an open space area
on the north side of El Fuerte Street in the city of Carlsbad, California. We understand erosion
occurred on a slope at the site. The erosion consists of gullies that have cut through the existing
slope surface materials and have undermined an existing concrete-lined brow ditch. The purpose
of our work is to provide conclusions and recommendations regarding the geotechnical aspects
of the project.
Atlas, formerly SCST, performed an erosion study at the site in March of 2017. This study was
conducted as a response to observed slope erosion and was summarized in a written report
presenting our conclusions and recommendations. The subsurface conditions were explored by
mapping and logging the materials exposed in the side walls of the gullies on the slope using field
measurements and observations. Additionally, four exploratory borings were advanced using
hand tools along the slope to depths of between about 41/2 to 6 feet below the existing ground
surface. An SCST geologist logged the borings and collected samples of the subsurface materials
encountered for laboratory testing.
An Atlas geologist conducted a site reconnaissance in May 2021 to observe the current surface
conditions of the erosional gullies and to measure any changes from the previously observed
conditions in March, 2017.
The materials encountered in the exploratory borings consist of fill and Quaternary-age colluvium.
The fill consists of moist, loose to medium dense, poorly-graded gravel with clay and sand, moist,
medium dense clayey sand with gravel, and medium stiff sandy lean clay. The colluvium consists
of medium dense silty and clayey sand. Groundwater was not encountered in the borings. At the
time of the site visit in 2017, wet conditions were present due to recent rain events. However, at
the time of our site visit in 2021, conditions were dry.
The main geotechnical conditions affecting the project are difficult excavation and backfill
conditions due to the presence of steep slopes, eroded soil, and cobbles and debris in the fill. In
order to reduce the potential for surficial erosion, we recommend vegetation and/or other man-
made erosion control measures be constructed on the fill slope. Additionally, debris greater than
12 inches in dimension may need to be removed.
Atlas No. 210120N
Report No. I
Page 1 1
1. INTRODUCTION
This report presents the results of the update geotechnical investigation Atlas performed for the
subject project. The site is located in an open space area on the north side of El Fuerte Street in
the city of Carlsbad, California. We understand erosion occurred on a slope at the site from
surface water flow over an existing brow ditch that was filled with soil and debris. The erosion
consists of gullies that have cut through the existing slope surface materials and have undermined
an existing concrete-lined brow ditch. The gullies extend from the brow ditch to the bottom of the
slope. Atlas, formerly SCST, previously performed an erosion study at the site in March of 2017.
The purpose of our work is to provide updated conclusions and recommendations regarding the
geotechnical aspects of the project. Figure 1 shows the site and surrounding vicinity.
1.1 Field Investigation
During the initial erosion study in 2017, the subsurface conditions were explored by mapping and
logging the materials exposed in the side walls of the gullies on the slope using field
measurements and observations. Additionally, four exploratory borings were advanced using
hand tools along the slope to depths of between about 4% to 6 feet below the existing ground
surface. Borings B-2 and B-3 were excavated within existing gullies. The gully sidewalls were
logged and included as part of the boring logs. Figure 2 shows the approximate location of the
borings. An SCST geologist logged the borings and collected samples of the subsurface materials
encountered for laboratory testing. The logs of the borings are presented in Appendix I. Soils are
classified according to the Unified Soil Classification System illustrated on Figure I-I.
An Atlas geologist conducted a site reconnaissance in May 2021 to observe the current surface
conditions of the erosional gullies and to measure any changes from the previously observed
conditions in 2017. Figure 2 shows the updated surface conditions.
1.2 Laboratory Testing
Selected samples obtained from the borings were tested to evaluate pertinent soil classification
and engineering properties and enable development of geotechnical conclusions and
recommendations. The laboratory tests consisted of grain size distribution and Atterberg limits.
The results of the laboratory tests, and brief explanations of test procedures, are presented in
Appendix II.
1.3 Analysis and Report
The results of the field and laboratory tests were evaluated to develop conclusions and
recommendations regarding:
Subsurface conditions along the slope repair.
Excavation conditions and the potential for difficult excavation.
Groundwater levels and the necessity for dewatering.
Allowable temporary excavation side slopes and the necessity for shoring.
Atlas No. 210120N
Report No. I
Page 1 2
Suitability of excavated materials for use as fill.
Appropriate types of fill materials as well as placement and compaction procedures.
SITE DESCRIPTION
The site is located in an open space area on the north side of El Fuerte Street, approximately 150
feet west of Chorlito Street. The slope is approximately 75 feet high and descends to the west at
an inclination of about 2:1 (horizontal to vertical). The upper approximately 20 feet of the slope is
within rear yard areas of lots in a residential subdivision. The top of the existing slope is located
approximately 130 feet west of Chorlito Street. A concrete-lined brow ditch separates the open
space area and the residential lots. Figure 3 presents a cross section. Erosion has occurred below
the brow ditch, undermining the concrete. The gullies extend from the brow ditch to near the toe
of the slope.
A concrete-lined storm water culvert, approximately 10 feet wide and 3 feet deep extends from a
concrete head wall at the bottom of the fill slope to the northwest for about 400 feet. A corrugated
metal pipe (CMP) exits the headwall and drains into the culvert. The CMP was observed to have
corrosion in its bottom allowing water to seep below the pipe and culvert.
The site was grubbed prior to our initial site visit to expose the erosional features. The area
supports native grasses, bushes, and trees. Site elevations range from approximately 360 feet
above mean sea level along Chorlito Street and 280 feet at the bottom of the slope near the
culvert.
SITE HISTORY
In 2017, aerial photographs of the property were obtained. Review of the aerial photographs
suggested the site consisted of a northwest-southeast trending drainage prior to residential
development. Mass grading appears to have been performed between the years of about 1967
to 1981. Generally, grading consisted of filling the drainage with about 75 feet of fill to create
building pads. The subject property includes a portion of the slope and drainage.
GEOLOGY AND SUBSURFACE CONDITIONS
The site is located within the Peninsular Ranges Geomorphic Province of California, which
stretches from the Los Angeles basin south into Baja California. This province is characterized as
a series of northwest-trending mountain ranges separated by subparallel fault zones and a coastal
plain of subdued landforms. The mountain ranges are underlain primarily by Mesozoic
metamorphic rocks that were intruded by plutonic rocks of the southern California batholith, while
the coastal plain is underlain by subsequently deposited marine and non-marine sedimentary
formations. The site is located in the coastal plain and is underlain by fill, Quaternary-age
colluvium, Tertiary-age Santiago Formation and Mesozoic-age metamorphosed and
unmetamorphosed volcanic and sedimentary rocks. The materials encountered in the exploratory
borings consist of fill and colluvium. The fill consists of moist, loose to medium dense, poorly-
Atlas No. 210120N
Report No. 1
Page 1 3
AI A e rrr7
graded gravel with clay and sand, moist, medium dense clayey sand with gravel, and medium
stiff sandy lean clay. The colluvium consists of medium dense silty and clayey sand.
Groundwater was not encountered in the borings; however, groundwater levels may fluctuate in
the future due to rainfall, irrigation, broken pipes, or changes in site drainage. At the time of our
site visit in 2017, wet conditions were present due to recent rain events. At the time of our site
visit in 2021, conditions were dry. Groundwater rise or seepage is difficult to predict, such
conditions are typically mitigated if and when they occur.
We understand erosion occurred in the form of gullies on the slope from surface water flow over
an existing brow ditch that was filled with soil and debris. In order to reduce the potential for further
erosion, we recommend the gullies be filled as presented herein and the brow ditch restored. The
main geotechnical conditions affecting the project are difficult excavation and backfill conditions
due to the presence of steep slopes, eroded soil, and cobbles and debris in the fill. In order to
reduce the potential for surficial erosion of the proposed fill slope, we recommend vegetation
and/or other man-made erosion control measures be constructed on the fill slope. Additionally,
debris greater than 12 inches in dimension may need to be removed.
6. RECOMMENDATIONS
The remainder of this report presents recommendations regarding earthwork construction as well
as geotechnical recommendations for the design of the proposed structures and improvements.
These recommendations are based on empirical and analytical methods typical of the standard
of practice in southern California. If these recommendations appear not to address a specific
feature of the project, please contact our office for additions or revisions to the recommendations.
6.1 Excavation Conditions
Medium dense fill and colluvium was observed during the initial field exploration in 2017.
However, dense formational materials mapped as Tertiary-age Santiago Formation and
Mesozoic-age metamorphosed and unmetamorphosed volcanic and sedimentary rocks can be
anticipated below the fill and colluvium. The contractor should anticipate hard digging conditions,
especially in deeper materials and have equipment capable of excavating dense materials on
difficult access slopes.
6.1.1 Temporary Excavation Slopes
Temporary slopes in fill and colluvium should not be steeper than 1:1 (horizontal:vertical). The
contractor's Competent Person should inspect the faces of temporary slopes daily before
personnel are allowed to enter the excavation area. Any zones of potential instability, sloughing
or raveling should be brought to the attention of the Engineer and corrective action implemented
before personnel begin working in the excavation.
Atlas No. 210120N
Report No. I
Page 1 4
Temporary slopes steeper than those described above will require shoring. Soldier piles and
lagging, internally braced shoring, or trench boxes could be used. Ground surface deformations
immediately adjacent to the trench could be greater where trench boxes are used compared to
other methods of shoring.
6.1.2 Site Preparation and Grading
Site preparation should begin with the removal of the vegetation and deleterious matter in areas
to receive fill. The existing fill exposed along the bottoms of the gullies should be excavated to
approximately 2 feet. An Atlas representative should observe the conditions exposed in the
bottom of the excavations to determine if additional excavation is required.
Where fill is to be placed within the erosional repair on surfaces inclined steeper than 5:1
(horizontal to vertical), benches should be excavated to provide a relatively level surface for fill
placement. Benches should extend through loose soils to expose competent material. An Atlas
representative should observe the conditions exposed in the bottom of the excavations to
determine if additional excavation is required.
A keyway should be established at the base of the fill slopes for the erosional repair. The keyway
should be at least equipment width at the bottom, extend at least 2 feet into competent material
and be sloped back at an inclination of about 2%. The keyway may need to be wider to
accommodate compaction equipment. Final keyway recommendations will depend on the
observations in the field.
6.1.3 Fill Material
In general, the on-site soil will be suitable for backfill material of the slope. Due to the lack of on-
site material, import fill will be needed. Imported fill should meet the recommended parameters
for Caltrans Embankment Fill as modified in the following tables and tested by Atlas prior to
transport to the site.
Table I - Import Fill Recommendations
Sieve Size
ASTM D422 Percent Passing
1'I'
W/ 1,-IIII
'IsII
(us
rzsis I4s
Atlas No. 210120N
Report No. I
Page 1 5
AI a e -rrrC7
6.1.4 Compacted Fill
Fill should be placed in 6 to 8-inch thick loose lifts, moisture conditioned to near optimum moisture
content, and compacted to at least 90% relative compaction. The maximum dry density and
optimum moisture content for the evaluation of relative compaction should be determined in
accordance with ASTM D1557. The compacted fill slope should not be constructed at an
inclination greater than 2:1 (horizontal:vertical) unless soil reinforcement is installed accordance
with manufacture's specifications and analysis by Atlas. Compaction of slopes should be
performed by back-rolling with a sheep foot compactor at vertical intervals of 2 feet or less as the
fill is being placed, and by track-walking the face of the slope when the fill is completed. As an
alternative, the fill slopes can be overfilled by at least 2 feet and cut back to expose dense material
at the design line and grade. All slopes are susceptible to surficial slope failure and erosion. Water
should not be allowed to flow over the top of slope. Additionally, slopes should be planted with
vegetation that will reduce the potential for erosion.
6.2 Geotechnical Engineering During Construction
The geotechnical engineer should review project plans and specifications prior to bidding and
construction to check that the intent of the recommendations in this report has been incorporated.
Observations and tests should be performed during construction. If the conditions encountered
during construction differ from those anticipated based on the subsurface exploration program,
the presence of the geotechnical engineer during construction will enable an evaluation of the
exposed conditions and modifications of the recommendations in this report or development of
additional recommendations in a timely manner.
7. CLOSURE
Atlas should be advised of changes in the project scope so that the recommendations contained
in this report can be evaluated with respect to the revised plans. Changes in recommendations
will be verified in writing. The findings in this report are valid as of the date of this report. Changes
in the condition of the site can, however, occur with the passage of time, whether they are due to
natural processes or work on this or adjacent areas. In addition, changes in the standards of
practice and government regulations can occur. Thus, the findings in this report may be
invalidated wholly or in part by changes beyond our control. This report should not be relied upon
after a period of two years without a review by us verifying the suitability of the conclusions and
recommendations to site conditions at that time.
In the performance of our professional services, we comply with that level of care and skill
ordinarily exercised by members of our profession currently practicing under similar conditions
and in the same locality. The client recognizes that subsurface conditions may vary from those
encountered at the boring locations and that our data, interpretations, and recommendations are
based solely on the information obtained by us. We will be responsible for those data,
interpretations, and recommendations, but shall not be responsible for interpretations by others
of the information developed. Our services consist of professional consultation and observation
Atlas No. 210120N
Report No. 1
Page 1 6
only, and no warranty of any kind whatsoever, express or implied, is made or intended in
connection with the work performed or to be performed by us, or by our proposal for consulting
or other services, or by our furnishing of oral or written reports or findings.
8. REFERENCES
International Code Council (2018), 2019 California Building Code, California Code of Regulations,
Title 24, Part 2, Volume 2 of 2, Based on the 2018 International Building Code, Effective
January 1, 2020.
Kennedy, M.P. and Tan, S.S. (2008), Geologic Map of the Oceanside 30' x 60' Quadrangle,
California, California Geological Survey, Scale 1:100,000.
Public Works Standards, Inc. (2018), "Greenbook" Standard Specifications for Public Works
Construction, 2018 Edition.
Southern California Soils and Testing (SCST, Inc.) (2017), Geotechnical Investigation, Rancho
Carrillo Master Association Erosion Study, Carlsbad, California, March 21.
Atlas No. 210120N
Report No. 1
Page 1 7
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SITE VICINITY MAP Date: June, 2021 Figure:
A - Rancho Carrillo Erosion Study By: MAW It I LM El Fuerte St & Chorlito St
Job No.: 210102N-1 1 Carlsbad, California
Figure:
2
Date: June, 2021
By: MAW
Job No.: 210102N-1
0 40' 80
Scale
Fence Bench
Brow
Ditch
I 3001 Ei------
B-4 I j
------------ A 15 I___-----
20° ---7
r~o 8
15°-- B-2
(6)
I
I
SUBSURFACE EXPLORATION MAP
Rancho Carrillo Erosion Study
El Fuerte St & Chorlito St
Carlsbad, California
Culvert
Headwall
LEGEND:
_____B-4 Approximate Location
(5) of Boring (Depth in Feet)
Current Areas of Erosion
(Gullies)
A A Location of Geologic
Cross-section
AI A
VIIII 16m
A'
- •-•._4 -ö___ - I
-
M !1
Chorlito
Street 4A
Brow •
35
a
-350
CI) Concrete-lined -340
ID Culvert - (0 -
-330 _ • Bench - o 32 Concrete a
Qf -320 0
a)
31 Headwall -
-310
a)
LU :300 W • Qf 290
• '7
Corrugated
- -290
• Qcol Metal
280
-
270 • Pipe 270
Horizontal Distance (feet)
LEGEND: In
Approximate Location of Boring
(Depth in Feet from Existing Slope Surface)
Approximate Location of Geologic
Contact, Queried Where Uncertain
Qf Fill
Qcol Colluvium
0 40' 80'
Scale 0
CROSS-SECTION Date: June, 2021 Figure:
Rancho Carrillo Erosion Study
El Fuerte St & Chorlito St By: MAW
Carlsbad, California Job No.: 210102N-1 3
TOP WIDTH OF FILL FILL OVER NATURAL SLOPE AS SPECIFIED BY THE
GEOTECHNICAL ENGINEER
COMPETENT MATERIAL ACCEPTABLE 3' TYPICAL BLANKET FILL IF
TO THE SOIL ENGINEER (FIRM SOILS - RECOMMENDED BY THE
FREE OF LOOSE OR DISTURBED SOILS) \ GEOTECHNICAL ENGINEER
COMPACTED FILL .:
FACE OF FINISHED SLOPE •.
...: .
HEEL DRAIN (SLOPED MINIMUM 2% . . • .. ... ...
TOWARD SUITABLE SUB-DRAIN OUTLET .. . .. . .. . .
OR TIED INTO NEAREST STORM DRAIN) ... .. ... . . . .... ..
SUB-DRAIN (SLOPED . .•. . VARIABLE
MINIMUM 2% TOWARD .. . . ..
SUITABLE OUTLET) . . . ....... .
:..••.••
MINIMUM HEIGHT OF BENCHES
IS 3 OR AS RECOMMENDED BY I THE GEOTECHNICAL ENGINEER 2' MINIMUM I MINIMUM 1' TILT BACK
KEY DEPTH L_ OR 2% SLOPE
(WHICHEVER IS GREATER)
HEEL DRAIN DETAIL* DETAIL OF SUB-DRAIN OUTLET*
overlap De inch open graded
Outlet Sloped FWah ade
Minimum 2% Fin
6 cubic feeftot
_Mi~rafi UON or Equal
a . roved equano slope to suitable outlet
Install 2'x2' No 3 Backing RIPRAP MI
Perforated Plpe* MlN -
* inch open QieJ Type II Energy Dissipater without wo-pentei Pa Pes(oTated Pipe' gra,el or equivalent headwall. Key in RIPRAP 3" mm. to
SUB-DRAIN IN STALLATI ON IIUUIJUI 7 DUUI U II III IJICUM.
Subdrain and heel drain pipe shall be installed with perforation down. *Drains located where drainage
SUB-DRAIN PIPE currently exist, and it is our evaluation
will not alter current drainage patterns.
Subdrain and heel drain pipe shall be 4" diameter PVC or ABS, type SDR35 NOT TO SCALE
AI A
STABILIZATION FILL DETAILS
Rancho Carrillo Erosion Study
El Fuerte St & Chorlito St
Carlsbad, California
Date: June, 2021
By: MAW
Job No.: 210102N-1
Figure:
APPENDIX I
SUBSURFACE EXPLORATION
Our previous field investigation consisted of mapping and logging the materials exposed in the
side walls of the gullies and excavating four exploratory borings with hand tools on February 13,
2017. Figure 2 shows the approximate boring locations. The field investigation was performed
under the observation of an Atlas geologist who also logged the borings and obtained disturbed
bulk samples of the materials encountered.
The soils are classified in accordance with the Unified Soil Classification System as illustrated on
Figure I-I. Logs of the test pits are presented on Figures 1-2 through 1-5.
SUBSURFACE EXPLORATION LEGEND
UNIFIED SOIL CLASSIFICATION CHART
SOIL DESCRIPTION GROUP
SYMBOL TYPICAL NAMES
COARSE GRAINED, more than 50% of material is larger than No. 200 sieve size.
GRAVELS CLEAN GRAVELS More than half of GW Well graded gravels, gravel-sand mixtures, little or no fines
coarse fraction is GP Poorly graded gravels, gravel sand mixtures, little or no fines. larger than No. 4
sieve size but, GRAVELS WITH FINES GM Silty gravels, poorly graded gravel-sand-silt mixtures. smaller than 3". (Appreciable amount of
fines) GC Clayey gravels, poorly graded gravel-sand, clay mixtures.
SANDS CLEAN SANDS More than half of SW Well graded sand, gravelly sands, little or no fines.
coarse fraction is SP Poorly graded sands, gravelly sands, little or no fines. smaller than No.
4 sieve size. SM Silty sands, poorly graded sand and silty mixtures.
SC Clayey sands, poorly graded sand and clay mixtures.
FINE GRAINED, more than 50% of material is smaller than No. 200 sieve size.
SILTS AND CLAYS ML Inorganic silts and very fine sands, rock flour, sandy silt or clayey-silt-
(Liquid Limit less sand mixtures with slight plasticity.
than 50) CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays,
silty clays, lean clays.
OL Organic silts and organic silty clays or low plasticity.
SILTS AND CLAYS MH Inorganic silts, micaceous or diatomaceous fine sandy or silty soils,
(Liquid Limit elastic silts.
greater than 50) CH Inorganic clays of high plasticity, fat clays.
OH Organic clays of medium to high plasticity.
HIGHLY ORGANIC SOILS PT Peat and other highly organic soils.
SAMPLE SYMBOLS LABORATORY TEST SYMBOLS
- Bulk Sample AL - Atterberg Limits
CAL - Modified California sampler CON - Consolidation
CK - Undisturbed Chunk sample COR - Corrosivity Tests
MS - Maximum Size of Particle (Resistivity, pH, Chloride, Sulfate)
ST - Shelby Tube DS - Direct Shear
SPT - Standard Penetration Test sampler El - Expansion Index
MAX - Maximum Density
GROUNDWATER SYMBOLS RV - R-Value
V - Water level at time of excavation or as indicated SA - Sieve Analysis UC - Unconfined Compression
- Water seepage at time of excavation or as indicated
Rancho Carrillo Master Association Erosion Study
Carlsbad, California
By: CJM I Date: June, 2021 --1'T"C1T---_.
Job Number: 160550N-1 Figure: I-I
LOG OF EXPLORATORY BORING B-I
Date Drilled: 2/13/2017 Logged by: CJM
Equipment: Hand Tools Project Manager: AKN
Elevation (ft): Depth to Groundwater (ft):Not encountered
- -
SAMPLES
I— . I-
I-
- I—.> Z >- I
SUMMARY OF SUBSURFACE CONDITIONS
2 co 0 Ui
a z Zo 0
5
o
ca
13
Sc FILL (Of): CLAYEY SAND with GRAVEL, moderate yellowish brown, fine grained, moist,
1/2 -
medium dense, cobble up to 4-inches in diameter encountered, fragments of sandstone
and concrete.
Moderate brown
SA
:T
-2%
CL SANDY LEAN CLAY, mottled brown and yellowish brown, fine grained, moist, medium
stiff. -3%
SA
-4
- 41/ - -
- PRACTICAL REFUSAL AT 41/2 FEET COBBLES
-5
51/2
-6
-6%
-7
71/2
-8
-8%
-9
91/2
-10— -- - --
. I Rancho Carrillo Master Association Erosion Study I I Carlsbad, California I
By: CJM June, 2021 I IJob Number: 160550N-1 1-2 I
LOG OF EXPLORATORY BORING B-2
Date Drilled: 2/13/2017 Logged by: CJM
Equipment: Hand Tools Project Manager: AKN
Elevation (ft): Depth to Groundwater (ft): Not encountered
() I— U) W
SA
Co
AL AL
)21
LOG OF EXPLORATORY BORING B-3
Date Drilled: 2/13/2017 Logged by: CJM
Equipment: Hand Tools Project Manager: AKN
Elevation (ft): Depth to Groundwater (ft):Not encountered
- -
SAMPLES
I
_cI) w i-
i C/) z o 0> iii a CO SUMMARY OF SUBSURFACE CONDITIONS W > —j 0
W —
0
Z 5e. U)
5
>-
0
Fx 0 o 0
SC FILL (Qfl: CLAYEY SAND with GRAVEL, moderate yellowish brown, fine grained, moist, - - - - -
1/2 loose, cobble up to 8-inches in diameter encountered.
-1
- 1/2 Moist to wet.
-2
-21h
-3 -- Approximate bottom of gully
.31/2
-4
.41/ — — PRACTICAL REFUSAL AT 41/2 FEET ON COBBLES
-5
-6
-61h
-7
71A
-8
-8Y2
-9
91/a
-10—
I I Rancho Carrillo Master Association Erosion Study
I Carlsbad, California I
By: CJM June, 2021 I I IJob Number: 160550N-1 1-4 I
LOG OF EXPLORATORY BORING B-4
Date Drilled: 2/13/2017 Logged by: CJM
Equipment: Hand Tools Project Manager: AKN
Elevation (ft): Depth to Groundwater (ft): Not encountered
- -
SAMPLES
uJ Cl)
.-. Z
I— I w
>- Cl) 0 Z øo 0 W D
CO SUMMARY OF SUBSURFACE CONDITIONS W > ()
w -
0
zo
5 I- in >-
2 0 0
- CL FILL (Qf): SANDY CLAY, reddish brown, fine grained, moist, medium stiff, cobble up to 4-
- - - -
- /2
inches encountered. ><
- COLLUVIUM (Qcofl: SILTY SAND, mottled light yellowish brown, fine grained, moist.
-
medium dense, massive, oxidation.
-
11/2
2 SA
21/2 Moderate gray, moist to wet.
3
-
-CLAYEY vg ht
oxidation.
41/2
- BORING TERMINATED AT 5 FEET
51/2
6
6%
7
10
Rancho Carrillo Master Association Erosion Study
Carlsbad, California
By: CJM June, 2021
Job Number: 160550N-1 I 1-5
APPENDIX II
LABORATORY TESTING
Laboratory tests were performed to provide geotechnical parameters for engineering analyses.
The following tests were performed:
CLASSIFICATION: Field classifications were verified in the laboratory by visual
examination. The final soil classifications are in accordance with the Unified Soil
Classification System.
GRAIN SIZE DISTRIBUTION: The grain size distribution was determined on four samples
in accordance with ASTM D422. The test results are presented on Figures Il-i through
11-4.
ATTERBERG LIMITS: The Atterberg limits were determined on two soil samples in
accordance with ASTM D4318. The test results are presented on Figures Il-I and 11-3.
Soil samples not tested are now stored in our laboratory for future reference and analysis, if
needed. Unless notified to the contrary, all samples will be disposed of 30 days from the date of
this report.
U.S. Standard Sieve Sizes
6" 3" 1-'12" 3/4" 3/8" #4 #8 #10 #16 #30 #40#50 #100 #200
100
90
80
-
70 2
0)
60
I- 0)
50 U.
00 40
ME
I- 0) a-
30
20
10
0
1000 100 10 1 0.1 0.01
Grain Size in Millimeters
Cobbles Gravel I Sand Silt or Clay
Coarse I Fine I Coarse I Medium I Fine
SAMPLE LOCATION
B-I at I to 2 Feet
I UNIFIED SOIL CLASSIFICATION: SC I
CLAYEY SAND with I DESCRIPTION GRAVEL
ATERBERG LIMITS
LIQUID LIMIT 50
PLASTIC LIMIT 20
PLASTICITY INDEX 30
Rancho Carrillo Master Association Erosion Study
Carlsbad, California
IL I By: CJM tDate: June, 2021
Job Number: 160550N-1 IFiqure: Il-I
U.S. Standard Sieve Sizes
6" 3" 1-W 3/4" 3/8" #4 #8 #10 #16 #30 #40#50 #100 #200
100
90
80
.2)70 0
60
C)
50
C
2 40 I- 0 a.
30
20
10
0
I 111111 $ I 111111 1 I 111111 1 I lit 111 1 I
1000 100 10 1 0.1 0.01
Grain Size in Millimeters
Cobbles Gravel I Sand Silt or Clay
Coarse I Fine I Coarse Medium I Fine
SAMPLE LOCATION UNIFIED SOIL CLASSIFICATION: CL
B-I at 3 to 4Y2 Feet DESCRIPTION SANDY LEAN CLAY
ATTERBERG LIMITS
LIQUID LIMIT NIT
PLASTIC LIMIT N/T
PLASTICITY INDEX N/T
Rancho Carrillo Master Association Erosion Study
Carlsbad, California
CJM IDate: JI
Number: 160550N-1
2021
11-2
U.S. Standard Sieve Sizes
6 3" 144° 3/4" 3/8° #4 #8 #10 #16 #30 #40#50 #100 #200
100 I
90
80
4- .c 2M 70 C)
60
50 N.
0040
30
20
10
0
I 111111 1 I 111111 1 I 111111 1 I 111111 1 I
1000 100 10 1 0.1 0.01
Grain Size in Millimeters
Cobbles Gravel Sand Silt or Clay
Coarse I Fine Coarse I Medium I Fine
SAMPLE LOCATION
B-2 at 0 to 1 Foot
UNIFIED SOIL CLASSIFICATION: GP-GC
POORLY GRADED
DESCRIPTION GRAVEL with CLAY
and SAND
ATTERBERG LIMITS
LIQUID LIMIT 34
PLASTIC LIMIT 24
PLASTICITY INDEX 10
Rancho Carrillo Master Association Erosion Study
Carlsbad, California
CJM IDate: Ju
ob Number: 160550N-1 lFiaure:
,2021
11-3
U.S. Standard Sieve Sizes
6" 3" 144" 3/4" 3/8" #4 #8 #10 #16 #30 #40 #50 #100 #200
100
90
80
4- .c 2 70
60
16.
50
040
30
20
10
1000 100 10 1 0.1 0.01
Grain Size in Millimeters
Cobbles Gravel Sand Silt or Clay
Coarse I Fine Coarse I Medium I Fine
SAMPLE LOCATION UNIFIED SOIL CLASSIFICATION: SM
B-4 at I to 31/2 Feet DESCRIPTION SILTY SAND
ATERBERG LIMITS
LIQUID LIMIT N/T
PLASTIC LIMIT NIT
PLASTICITY INDEX N/T
Rancho Carrillo Master Association Erosion Study
Carlsbad, California
CJM IDate: Ji
Number: 160550N-1 lFiaure:
,2021
11-4
APPENDIX III
PHOTO APPENDIX
0 9 5 t t)C 1 1, 12677 117.2448,31-1 ±17 m 63 m
, 7tm
097E( •33.112704,-172443-4rrrA54m
- '
-- ,-
-~ — •_•( '4
PHOTO - I
PHOTO —3
) 14 L • 33.11 24db, 1i/.4445 ni A 77 m
T, iit
- -i.-
1'
-,
'
-- - • -•
- 4
- •,•r
- __;_'$ 7' - • 'I
•-2-s'
- ' - -_ -,• - •
-•--% -. t — .7 c -
- -
PHOTO —2
PHOTO —4
IWO
27/6'W T) S 31, 117558, - 7.244443 7 mA 71 m
4;
ol
:'- •- ••••
-
____
4it
PHOTO - 5 PHOTO —
All L l ir
-álK4±
0(I). 33.112519,-117.244333 ±8 m 57 m 0 1088 (T) 33.112621, -117.244673±5 m A40 m
AKIO
till
F J
f.4 41 ;q?
.,
- 4
- - - - -- ---- -I.---- -
'-.4a • -- -
—
121E. 33.11276,117 44777 drii A 60 m 34 NE (I) 0 33 249 -117.244376 ±7 m A 58 m
-> -
c, 10
-. - '• - ¼ - -
:
-ti
r
- •.-
-•'.- .,4..- •"-•"S'-4 -••
PHOTO-7 PHOTO-8 PHOTO-9
PHOTO APPENDIX
k Rancho Carrillo Erosion Study Date: June, 2021 Appendix:
ILm El Fuerte St & Chorlito St By: MAW
Carlsbad, California Job No.: 210102N-1 111-3