HomeMy WebLinkAboutMS 05-10; EUCALYPTUS LANE; PRELIMINARY GEOTECHNICAL INVESTIGATION FOR THE PROPOSED SINGLE-FAMILY RESIDENCE; 2018-05-11Inland Engineering Technologies Inc.
May 11, 2018
Mr. Guy Oliver
4992 Eucalyptus Lane
Carlsbad, CA 92008
41655 Reagan Way Ste. E
Murrieta, CA. 92562
Ph: (951) 894-6464
Fax: (951) 894-6491
Project No. 16-3319
Subject: Preliminary Geotechnical Investigation for the Proposed Single-Family Residence Located at
4984 Eucalyptus Lane, City of Carlsbad, County of San Diego, California
Inland Engineering Technologies, Inc. (IET) is pleased to submit herewith our preliminary geotechnical
investigation report for the proposed single-family residence located at 4984 Eucalyptus Lane, City of Carlsbad,
County of San Diego, California. IET previously performed a preliminary geotechnical investigation for the
adjacent property at 4992 Eucalyptus Lane owned by you (IET, 2015). The current report presents previous and
current results of IET' s field investigation, laboratory testing and our engineering judgment, opinions,
conclusions, and recommendations pertaining to the geotechnical design aspects of the proposed development.
It has been a pleasure to be of service to you on this project. Should you have any questions regarding the
content of this report or should you require additional information, please contact this office at your earliest
convenience.
Respectfully submitted,
INLAND ENGINEERING TECHNOLOGIES, INC.
Worl
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Geotechnical Engineer
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TABLE OF CONTENTS
Section Page
1.0 INTRODUCTION .............................................................................................................. 1
1.1 Purpose and Scope of Services ................................................................................. 1
1.2 Location and Site Description ................................................................................... 1
1.4 Subsurface Investigation ........................................................................................... 2
2.0 GEOTECHNICAL CONDITIONS .................................................................................. 2
2.1 Local Geology and Soil Conditions .......................................................................... 2
2.2 Groundwater ............................................................................................................. 2
2.3 Liquefaction ............................................................................................................. 2
2.4 Seismic-Induced Settlement ....................................................................... 3
2.5 Tsunamis and Seiches .............................................................................................. 3
2.6 Seismic Design Parameters ...................................................................................... 3
2. 7 Slope Stability .......................................................................................................... 3
2.8 Laboratory Testing .................................................................................................... 4
3.0 CONCLUSIONS ................................................................................................................ 4
4.0 RECOMMENDATIONS ................................................................................................... 4
4.1 Site Earthwork .......................................................................................................... 4
4.1.1 SitePreparation ............................................................................................ 4
4.1.2 Removal and Recompaction ......................................................................... 5
4.1.3 Import Soils for Grading ............................................................................... 5
4.1.4 Temporary Stability of Removal Excavations ............................................... 5
4.1.5 Fill Placement and Compaction .................................................................... 5
4.1.6 Trench Backfill and Compaction .................................................................. 6
4.2 Foundation Selection ............................................................................................... 6
4.2.1 Conventional Foundations ............................................................................ 6
4.2.2 Post-Tensioned Slab Foundation System ........................................ 6
4.2.3 Foundation Settlement .............................................................. 7
4.2.4 Building Floor Slab ................................................................. 7
4.3 Structural Setbacks .................................................................................................. 7
4.4 Corrosivity to Concrete and Metal.. ......................................................................... 7
4.5 Control of Surface Water and Drainage Control ..................................................... 8
4.6 Slope Landscaping and Maintenance ........................................................................ 8
4. 7 Future Plan Reviews & Construction Observation and Testing .............................. 8
5.0 LIMITATIONS .................................................................................................................... 9
LIST OF TABLES, FIGURES AND APPENDICES
Tables
Table 1 -Seismic Design Parameters (Page 3)
Figures
Figure 1 -Site Location Map (Front of the text)
Figure 2 -Boring Location Map (Rear of the text)
Appendices
Appendix A -References (Rear of Text)
Appendix B -Field Exploration (Rear of Text)
Appendix C-Laboratory Test Procedures and Test Results (Rear of Text)
Project No. 16-3319 Page ii May 11, 2018
Inland Engineering
/J'\ Technologies Inc. ~
Geotechnical • Materials Testing • Special Inspections
FIGURE 1
SITE LOCATION MAP
4c~ EUCALYPTUS LANE
CARLSBAD, CALIFORNIA
Project Name
yp
Scale Not To Scale
Date Au ust 2015
1.0 INTRODUCTION
1.1 Purpose and Scope of Services
The main purpose of IET's subsurface investigation was to evaluate the pertinent geotechnical
conditions at the site and to provide geotechnical design criteria for grading construction, foundation
design, and other relevant aspects relative to the proposed development of the site. This report presents
the results of previous geotechnical investigation that is applicable to the subject site and the current
geotechnical investigation for the proposed development.
IET's scope of services included:
• Review of previous geotechnical reports and geologic maps pertinent to the site (Appendix A).
• A subsurface investigation including the excavation, sampling, and logging of one (1) boring log. Log
of the boring is presented in Appendix B, and its approximate location is depicted on Figure 2. The
boring was excavated to evaluate the general characteristics of the subsurface conditions on the site
including classification of site soils, determination of depth to groundwater, and to obtain
representative soil samples.
• Geologic mapping of the site.
• Laboratory testing of representative soil samples obtained during our subsurface investigation
(Appendix C).
• Liquefaction analyses.
• Engineering and geologic analysis of the data with respect to the proposed development.
• Preparation of this report presenting our findings, conclusions and preliminary geotechnical
recommendations for the proposed development.
1.2 Location and Site Description
The subject site is located at 4984 Eucalyptus Lane, City of Carlsbad, County of San Diego, California.
The general location of the site is shown on Figure 1 -Site Location Map. IET's site reconnaissance
indicated the subject site currently vacant. Associated improvements included drive way, landscaping,
and utilities.
1.3 Proposed Development
No preliminary plans of the proposed structure were available for our review at the time this report was
prepared. It is our understanding that a two-story home is proposed at the subject site. The proposed
structure will be a wood frame structure. Associated improvements will include utility lines and
landscaping.
1.4 Subsurface Investigation
IET's subsurface investigation was performed on March 28, 2018, which consisted of one (1) hand auger
boring, B-3, to a depth of approximately 4 feet below existing ground surface. IET's attempt to advance the
boring to a deeper depth encountered refusal. IET previously performed subsurface exploration on July 6,
2015 on the adjacent property at 4992 Eucalyptus Lane. This exploration consisted of two (2) hollow stern
auger borings to depths ranging from about 11 ½ to 51 ½ feet below existing ground surface (IET, 2015)
The approximate location of the boring is shown on Figure 2-Boring Location Map. At the conclusion of
the subsurface investigation, the boring was backfilled with native materials. Minor settlement of the
backfill soils may occur over time.
During our subsurface investigation, representative bulk samples were retained for laboratory testing.
Laboratory testing was performed on representative soil samples and included in-situ density and
moisture content, #200 wash, Atterberg Limits, and Expansion Index. A discussion of the tests
performed and a summary of the results are presented in Appendix C.
2.0 GEOTECHNICAL CONDITIONS
2.1 Local Geology and Soil Conditions
The earth materials on the site are primarily comprised of top soil and quaternary old alluvial flood plain
deposits. A general description of the earth materials observed on the site is provided in the following
paragraphs:
• Top Soil: Top soil was encountered in the upper two feet below the existing surface. This material
generally consisted of brown, moist, very stiff, sandy clay.
• Quaternary Old Alluvial Flood Plain Deposits (Ooa): Quaternary old alluvial flood plain deposits
(Qoa) were encountered below the top soil to the maximum depth explored of approximately 51 ½
feet below ground surface (included previously drilled borings). This alluvial unit consists
predominately of light brown to brown, moist, very dense, fine to coarse grained silty sand. Also
encountered were light brown to brown, moist, very stiff to hard sandy clay and sandy silt.
2.2 Groundwater
Groundwater was not encountered in the current and previous subsurface investigation. The subject site has
relatively high relief locally. Therefore, shallow historic high groundwater is not anticipated at least in the
upper 25 feet.
2.3 Liquefaction
Liquefaction is a seismic phenomenon in which loose, saturated, granular soils behave similarly to a
fluid when subject to high-intensity ground shaking. Liquefaction occurs when three general conditions
exist: 1) shallow groundwater; 2) low density non-cohesive (granular) soils; and 3) high-intensity ground
motion. Studies indicate that saturated, loose to medium dense, near surface cohesionless soils exhibit
Project No. 16-3319 Page2 May 11, 2018
the highest liquefaction potential, while dry, dense, cohesionless soils and cohesive soils exhibit low to
negligible liquefaction potential.
Due to the absence of shallow groundwater and the dense nature of the subsurface soils, the potential for
liquefaction at the site is considered nil.
2.4 Seismic-Induced Settlement
Since relatively high blow counts were recorded in the borings, a negligible amount of seismic-induced
-settlement in dry sand is anticipated; however, for design purposes, a seismic-induced settlement of¼-
inch may be assumed. Seismic-induced differential settlement may be assumed to be approximately one-
half of the total seismic-induced settlement. Therefore, a seismic-induced differential settlement of
approximately 1/8-inch may be assumed over a span of 30 feet in the design.
2.5 Tsunamis and Seiches
Based on the elevation of the subject site with respect to sea level and its distance to large open bodies of
water, the potential of seiche and/or tsunami is considered to be remote.
2.6 Seismic Design Parameters
The seismic design parameters were determined in accordance with 2010 ASCE 7 (with March 2013
errata). A site coordinate of 33.15096° N, 117.30242° W was used to derive the seismic parameters
presented below.
Table 1-Seismic Design Parameters
Seismic Soil Parameters
Site Class Definition D
Mapped Spectral Response Acceleration Parameter Ss 1.082
Mapped Spectral Response Acceleration Parameter, S1 0.416
Site Coefficient Fa 1.067
Site Coefficient Fv 1.584
Adjusted Maximum Considered Earthquake (MCE) Spectral Response Acceleration 1.155 Parameter SMs
Adjusted Maximum Considered Earthquake (MCE) Spectral Response Acceleration 0.659 Parameter SM1
Design Spectral Response Acceleration Parameter, Sos 0.770
Design Spectral Response Acceleration Parameter, Soi 0.440
2. 7 Slope Stability
No slopes more than 30 feet in height and steeper than 2: 1 (h:v) in inclination is anticipated, therefore, it
is our conclusion that no slope stability analysis is needed at this time.
Project No. 16-3319 Page3 May 11, 2018
2.8 Laboratory Testing
Laboratory tests werte performed on representative samples obtained from the borings and included in-situ
density and moisture content, #200 wash, Atterberg Limits, and Expansion Index (EI). Expansion Index
testing of a representative sample of the upper 5 feet of the onsite soils indicated an Expansion Index of
53 ("Medium" per ASTM D4829). A discussion of the tests performed and a summary of the results are
presented in Appendix C.
3.0 CONCLUSIONS
Based on the results of our geotechnical investigation, it is our opinion that the proposed development is
feasible from a geotechnical standpoint, provided the conclusions and recommendations contained in this report
are considered and incorporated into the project design process. The following is a summary of the primary
geotechnical factors determined from our geotechnical investigation.
• Based on our subsurface exploration and review of pertinent geologic maps and reports, the site is underlain by
top soil and quaternary old alluvial flood plain deposits.
• Groundwater is not anticipated to be a constraint for the proposed development.
• Based on the review of the data, field exploration, and analyses the potential for liquefaction at the site is
considered nil.
• The upper soils of the subject site should be considered to have a medium expansion potential in accordance
with ASTM D4829.
• Based on our project expertise, the onsite soils should be considered to have a high corrosion potential for
metals due to low resistivity.
• Due to the medium expansive nature of the onsite soils, the proposed building floor slab and foundation
system should be structurally stiffened. In lieu of structural mitigation, at least 3 feet of very low expansive
import soils may be placed below the lowest grade of the proposed foundation.
• It is anticipated that the onsite soils may be excavated with conventional heavy-duty construction equipment.
4.0 RECOMMENDATIONS
4.1 Site Earthwork
We anticipate that earthwork at the site will consist of site preparation and remedial grading followed by
construction of slab-on-grade type foundations. All earthwork and grading should be performed in
accordance with all applicable requirements of the appropriate reviewing agency.
4.1.1 Site Preparation
Prior to grading of areas to receive structural fill or engineered structures, the areas should be cleared
of surface obstructions, any existing debris, and stripped of vegetation. Vegetation and debris should
be removed and properly disposed of offsite. All debris from the proposed demolition activities at
Project No. 16-3319 Page4 May 11, 2018
the site should be removed and properly disposed of offsite. Areas to receive fill and/or other
surface improvements should be scarified to a minimum depth of 6 inches, brought to a near-
optimum moisture condition, and recompacted to at least 90 percent relative compaction (based on
ASTM D1557).
4.1.2 Removal and Recompaction
Compressible materials not removed by the planned grading should be excavated to competent
material and replaced with compacted fill soils. In the building footprint, at least the upper 5 feet
below the existing grade or 3 feet below the proposed footing bottoms, whichever is deeper, should
be removed and replaced as compacted fill. The removal and recompaction should be extended to at
least 5 feet outside the building footprint.
In the pavement area, the upper 1 foot should be removed and recompacted. Localized, deeper
removals should be anticipated where deemed necessary by the geotechnical consultant based on
observations during grading.
4.1.3 Import Soils for Grading
In the event import soils are needed to achieve final design grades, all potential import materials
should be free of deleterious/oversize materials (greater than 6 inches in dimension), non-
expansive, and approved by the project geotechnical consultant prior to commencement of
delivery onsite.
4.1 .4 Temporary Stability of Removal Excavations
All excavations for the proposed development should be performed in accordance with current
OSHA (Occupational Safety and Health Agency) regulations and those of other regulatory
agencies, as appropriate.
Temporary excavations maybe cut vertically up to four feet. Excavations over four feet should be
slot-cut, shored, or cut to a lH:lV (horizontal, H: vertical, V) slope gradient. Surface water should
be diverted away from the exposed cut, and not be allowed to pond on top of the excavations.
Temporary cuts should not be left open for an extended period of time.
4.1.5 Fill Placement and Compaction
Areas prepared to receive structural fill and/or other surface improvements should be scarified to a
minimum depth of 6 inches, brought to at least optimum-moisture content, and recompacted to at
least 90 percent relative compaction (based on ASTM D1557). The optimum lift thickness to
produce a uniformly compacted fill will depend on the type and size of compaction equipment
used. In general, fill should be placed in uniform lifts generally not exceeding 8 inches in
compacted thickness. Placement and compaction of fill should be performed in accordance with
local grading ordinances under the observation and testing of the geotechnical consultant.
Project No. 16-3319 Page5 May 11, 2018
4.1.6 Trench Backfill and Compaction
The onsite soils may generally be suitable as trench backfill provided they are screened of rocks and
other material over 6 inches in diameter and organic matter. Trench backfill should be compacted in
uniform lifts (generally not exceeding 8 inches in compacted thickness) by mechanical means to at
least 90 percent relative compaction (per ASTM D1557).
If trenches are shallow and the use of conventional equipment may result in damage to the
utilities; clean sand, having sand equivalent (SE) of 30 or greater, should be used to bed and
shade the utilities. Sand backfill should be densified. The densification may be accomplished by
jetting or flooding and then tamping to ensure adequate compaction. A representative from IET
should observe, probe, and test the backfill to verify compliance with the project specifications.
4.2 Foundation Selection
Two foundation options are provided herein: (1) conventional foundation, and (2) post-tensioned slab
foundation system. The information and recommendations presented in this section are not meant to
supersede design by the project structural engineer or civil engineer specializing in the structural design nor
a corrosion consultant. When the final foundation plan for the proposed structure is known, the plan should
be provided to our office to verify the recommendations presented herein.
4.2.1 Conventional Foundations
Conventional shallow foundation system may be used to support the proposed structure. Grade
beams should be constructed to minimize the anticipated differential settlement of the foundations.
Exterior continuous footings may be founded at a minimum depth of 18-inch. Shallow
foundations may be designed for a maximum allowable bearing capacity of 1,500 lb/ft2 for 12-
inch continuous and 24-inch spread footings with a minimum of 18 inches embedment into
certified compacted fill. The bearing capacity value may be increased by 1/3 for wind load and
seismic load. A factor of safety greater than 3 was used in evaluating the above bearing capacity
values. The bearing capacities should be re-evaluated when loads and footing sizes have been
finalized.
Lateral forces on footings may be resisted by passive earth resistance and friction at the bottom
of the footing. Foundations may be designed for a coefficient of friction of 0.35, and a passive
earth pressure of 250 lb/ft2/ft. The passive earth pressure incorporates a factor of safety of about
1.5. When combining passive and friction forces, passive resistance should be reduced by 1/3.
All footing excavations should be cut square and level and should be free of sloughed materials.
4.2.2 Post-Tensioned Slab Foundation System
In-lieu of a conventional foundation system, a post-tensioned slab foundation system may be used
to support the proposed structure. A post-tensioned slab should have sufficient rigidity to span over
voids that may develop under the slab due to differential settlement. Additional recommendations
for a post-tensioned slab foundation system can be provided upon request.
Project No. 16-3319 Page 6 May 11, 2018
4.2.3 Foundation Settlement
A static settlement of approximately ¼-inch is anticipated. Therefore, a total settlement of
approximately ½-inch is anticipated due to all causes (static and seismic). For design purposes
differential settlement may be assumed to be approximately one-half of the total settlement.
Based on the above, the estimated differential settlement that may be considered in site
development is approximately ¼-inch over the span of 30 feet.
4.2.4 Building Floor Slab
As a minimum, 5-inch thick slab, reinforced with #4 bars, 18-inch on center both ways, is
recommended, provided at least the upper 3 feet of the subgrade soils are very low expansive in
accordance with ASTM D4829. Interior floor slabs with moisture sensitive floor coverings
should be underlain by a 15-mil thick moisture/vapor barrier to help reduce the upward migration
of moisture from the underlying subgrade soils. The moisture/vapor barrier product used should
meet the performance standards of an ASTM E 1745 Class A material and be properly installed
in accordance with ACI publication 302. It is the responsibility of the contractor to ensure that
the moisture/vapor barrier systems are placed in accordance with the project plans and
specifications, and that the moisture/vapor retarder materials are free of tears and punctures prior
to concrete placement. Additional moisture reduction and/or prevention measures may be
needed, depending on the performance requirements of future interior floor coverings.
Sand layer requirements are the purview of the structural engineer and should be provided in
accordance with ACI Publication 302 "Guide for Concrete Floor and Slab Construction".
Ultimately, the design of the moisture retarder system and recommendations for concrete
placement and curing are the purview of the foundation engineer, in consideration of the project
requirements provided by the architect and developer.
Prior to placing concrete, the subgrade soils be floor slabs should be pre-watered to achieve a
moisture content that is at least equal or slightly greater than optimum moisture content. This
moisture content should penetrate to a minimum depth of 18 inches into the subgrade soils.
4.3 Structural Setbacks
4.4
Structural setbacks, in addition to those required per the 2016 CBC, may be required depends on the
stability of the seawall and the backyard slope.
Corrosivity to Concrete and Metal
Corrosivity testing should be performed at the completion of the grading if required. As a minimum,
corrosivity testing should include soluble Sulfate content, Chloride content, minimum resistivity, and
pH. IET can conduct additional testing (if required) to evaluate the actual corrosion potential of the site
and to provide recommendations to reduce the corrosion potential with respect to the proposed
improvements.
Project No. 16-3319 Page 7 May 11, 2018
4.5 Control of Surface Water and Drainage Control
Positive drainage of surface water away from structures is very important. No water should be allowed to
pond adjacent to structures. Positive drainage may be accomplished by providing drainage away from
structures at a gradient of at least 2 percent for a distance of at least 5 feet, and further maintained by a
swale or drainage path at a gradient of at least 1 percent. Where necessary, drainage paths may be
shortened by use of area drains and collector pipes.
Planters with open bottoms adjacent to structures should be avoided. Planters should not be designed
adjacent to structures unless provisions for drainage, such as catch basins, liners, and/or area drains, are
made. Over watering must be avoided.
4.6 Slope Landscaping and Maintenance
Adequate slope and pad drainage facilities are essential in the design of the finish grading for the subject
site. The overall stability of graded slopes should not be adversely affected provided all drainage
provisions are properly constructed and maintained thereafter and provided all engineered slopes are
landscaped with a deep rooted, drought tolerant and maintenance free plant species, as recommended by
the project landscape architect.
4. 7 Future Plan Reviews, Construction Observation and Testing
Future plan reviews are necessary to ensure that recommendations and conclusions from Inland
Engineering Technologies, Inc. feasibility and preliminary studies have been incorporated into the plans.
Modifications to the plan may arise from our review therefore our review should be performed as soon
as practical. Such reviews should include, but are not limited to:
❖ Foundation Plans
❖ Storm Drain/Sewer/Water/Dry Utility Plans
Plans should be forwarded to the project geotechnical engineer and/or engineering geologist for review and
comments, as deemed necessary. In addition, the grading plan should reference the approved soils report
and indicate that all grading shall be performed as recommended by the approved report. IET should
review the grading and foundation plans to verify compliance of these documents with their
recommendations by signing and stamping.
The recommendations provided in this report are based on limited subsurface observations and
geotechnical analysis. The interpolated subsurface conditions should be checked in the field during
construction by a representative of IET.
Construction observation and testing should also be performed by the geotechnical consultant during future
grading, excavations, backfill of utility trenches, preparation of pavement subgrade and placement of
aggregate base, foundation or retaining wall construction or when an unusual soil condition is encountered
at the site. Grading plans, foundation plans, and final project drawings should be reviewed by this office
prior to construction.
Project No. 16-3319 Page8 May 11, 2018
5.0 LIMITATIONS
IET' s services were performed using the degree of care and skill ordinarily exercised, under similar
circumstances, by reputable engineers and geologists practicing in this or similar localities. No other
warranty, expressed or implied, is made as to the conclusions and professional advice included in this
report. The samples taken and submitted for laboratory testing, the observations made and the in-situ field
testing performed are believed representative of the entire project; however, soil and geologic conditions
revealed by excavation may be different than our preliminary findings. If this occurs, the changed
conditions must be evaluated by the project soils engineer and geologist and design(s) adjusted as required
or alternate design(s) recommended.
This report is issued with the understanding that it is the responsibility of the owner, or of his/her
representative, to ensure that the information and recommendations contained herein are brought to the
attention of the architect and/or project engineer and incorporated into the plans, and the necessary steps
are taken to see that the contractor and/or subcontractor properly implements the recommendations in the
field. The contractor and/or subcontractor should notify the owner if they consider any of the
recommendations presented herein to be unsafe.
The findings of this report are valid as of the present date. However, changes in the conditions of a
property can and do occur with the passage of time, whether they be due to natural processes or the
works of man on this or adjacent properties.
In addition, changes in applicable or appropriate standards may occur, whether they result from
legislation or the broadening of knowledge. Accordingly, the findings of this report may be invalidated
wholly or partially by changes outside our control.
Project No. 16-3319 Page9 May II, 2018
APPENDIXA
REFERENCES
APPENDIXA
References
California Geological Survey (CGS), 2007 Geologic Map of the Oceanside 30'x60' Quadrangle, California,
Compiled by Michael P. Kennedy and Siang S. Tan
___ ., 1998, Seismic Hazard Zones Map, Anaheim Quadrangle, Dated April 15
Charles W. Jennings and George J. Saucedo, 1999, Simplified Fault Activity Map of California
IET, 2015, Preliminary Geotechnical Investigation for the Proposed Single-Family Residence Located at 4992
Eucalyptus Lane, City of Carlsbad, County of San Diego, California, Project No.:15-3071, Dated
August 4
Ishihara, K. 1985, Stability of Natural Deposits During Earthquakes, Proceedings 11 th International Conference
On Soil Mechanics and Foundation Engineering, San Francisco, Volume 2
___ , 1995, Effects of At-Depth Liquefaction on Embedded Foundations During Earthquakes, Proceedings of
11th Asian Regional Conference on Soil Mechanics and Foundation Engineering, Volume 2
APPENDIXB
FIELD EXPLORATION
APPENDIXB
Field Exploration
B-1 General
IET' s personnel carried out a reconnaissance of the site. The location of the exploratory excavation was
chosen to obtain subsurface information needed to achieve the objective for this investigation.
A visual survey was conducted to verify that the proposed excavations would not encounter any
subsurface utility lines. No underground lines were encountered during the field exploratory program.
B-2 Excavation, Drilling and Sampling
The subsurface exploration program for this project was performed on March 28, 2018 and consisted of
one (1) hollow stem auger boring, B-3, to depth of about 3½ feet below existing ground surface. The
approximate location of the borings is shown on Figure 2 -Boring Location Map.
The previously performed subsurface exploration on July 6, 2015 and consisted of two (2) hollow stem
auger borings, B-1 and B-2, to depths ranging from about 11 ½ to 51 ½ feet below existing ground surface.
The approximate location of the borings is shown on Figure 2 -Boring Location Map.
Borings were excavated using a truck-mounted, 8-inch-diameter hollow-stem auger drill rig supplied by
Discovery Drilling company of California. The boring was excavated and sampled at regular intervals:
generally, every 5 feet to the maximum excavated depth of each boring. The boring was sampled using a
2-3 /8 inch-inside-diameter (ID) Modified California Sampler or a 1-3/8-inch ID Standard Penetration
Test (SPT) sampler. Samples were obtained as the sampler was driven into the bottom of the boring by a
140-pound automatic-trip hammer free falling from a height of 30 inches.
The ring samples were placed in plastic cans, labeled, and transported to the laboratory. The SPT soil
samples were examined and carefully removed from the sampler, bagged, sealed, labeled, and
transported to the laboratory for testing as well.
Bulk samples also were collected during the course of drilling by taking cuttings obtained from the auger
flights. The bulk samples were selected for classification and testing purposes and may represent a
mixture of soils within the noted depths. Recovered samples were bagged and returned to the laboratory
for further classification and testing.
B-3 Miscellaneous
The boring logs describe the earth materials encountered, sampling method used, and field and
laboratory tests performed. The logs also show the boring number, date of completion, and the name of
the logger and drilling subcontractor. A representative of IET logged the borings in accordance with the
Standard Practice for Description and Identification of Soils (Visual-Manual Procedure) ASTM D2488.
The boundaries between soil types shown on the logs are approximate and the transition between
different soil layers may be gradual. The logs of the borings are presented on the following pages.
Geotechnical Boring Log B-1 (Previously Drilled)
Date: 7/6/2015 Page: 1 of 1
Project Name: SFR-Carlsbad at 4992 Project Number: 15-3071
Drilling Company: Discovery Type of Rig: CME-75
Drive Weight: 140Ibs Drop: 30" Hole Dia: 8"
Elevation of Top of Hole: -Hole Location: See Fiaure 2
..... c.=-DESCRIPTION (l) (.)
.0 s 0 g 0) E ->-~ .0 1n 0 :::::, C -0 E (l) .....I z :::::, ·oo ->-I-C g 0 (.) (l) 0 C (l) CJ) -..... :.:::i .c. E a. u (l) :::::, CJ) 0 ro 0 -Logged By: DD -a. E 3: en u (l) > a. ro ~ ·5 a. (l) (l) ..... ro 0 CJ) >-w 0 (9 CJ) CD 0 ~ ::::> Sampled By: DD I-
0 'i!\' ' ,,,.,,} CL Top Soil ,.,,,., ·•, 'ii' ..... Sandy CLAY: brown, moist, very stiff
;11}:s[ iit, --------1 ··-~r---------------------------------------------------------,,. R-1 113 11 Quaterna!:l£ Old Alluvial Flood Plain Deposits 1,im,;: % {Qoa)
' '" ,,,, ,, Sandy CLAY: brown, moist, hard ',, ....
-5 -1 : /A ? I 15
Ii \< \\ R-2 14 118 11 Liquid Limit (LL)=36, Plastic Limit (PL)=27, Atterberg
19 Plasticity Index (Pl)=9 !!: .;;:i:;· Limits
)(\:/\\. ------------------------------------·--.................................................................................................................................................................... ----·
I ML
R-3 7 107 8 Sandy SILT: light brown, moist, very stiff
I 'iii
13 14
-10 -I 10 hard, passing #200 = 61 % R-4 19 114 9 #200wash
25
.....
---------~ ................ --------.................... ----------------------------------------------------------------------.. SM .....
-15 -.. 5 .. SPT-1 ¼ Silty SAND:light brown, moist, very dense, fine .. 9 #200wash
.... 10 to medium grained, passing #200 = 24% . . ..... .. . . . . . .. .....
.. .....
-20 -. -5 .. more silt, passing #200 = 33% SPT-2 ~ 12 #200wash
14
.. -. . . . -
.. --25 -..
SPT-3 ~ 6 more sand 19
-20
--
..... . . . . . . . ..... -30 -.. .. . .
I .-.1c11.-.c:1 E .-.9 1.-.~~r1.-.9
--.-~c::h.-.e>le>gi~s. 1.-.c::_ ~
G-eotechnica.I -1'-'1:a.teria.ls Testing• Special Inspections
Geotechnical Boring Log B-1 (Previously Drilled)
Date: 7/6/2015 Page: 2 of 2
Project Name: SFR-Carlsbad Project Number: 15-3071
Drilling Company: Discovery Type of Rig: CME-75
Drive Weight: 1401bs Drop: 30" Hole Dia: 8"
Elevation of Too of Hole: Hole Location: See Fiaure 2
,.__ c;::::-DESCRIPTION Cl) 0 ..c _e, 0 g O> E ~ ..c en c >-E 0 ~ -e....... Cl)
C ...--_J z ~ ·u5 >-I-
0 s -~ Cl) 0 C ~ Cf) -= ..c ..c a.. 0 Cl) ~ Cf) 0 ro 0 -Logged By: DD > a. a.. E :s: en 0 Cl)
Cl) ro 0 >-·o Cf) a.. Cl) ,.__ ro ,.__ >-w 0 (..9 Cf) CD 0 ~ :::) Sampled By: DD I-
.... 8 Silty SAND: brown, very dense, fine to 30 . . . ' SPT-4 ~ SM #200wash ~ . . . ' . 14 . . . . . 15 coarse grained, passing #200 = 23% . . -... . . . . . . -. '
...... ... ' -
. . . . . . ,-
'.
-35 -. . ... -.. 10 more silt . .
SPT-5 X ...... 17 -23
... . . . ,_
. . ,_ ...... . .
,_
..... . . . . . . -40 -14 ..... ' SPT-6 X . . . 17 fine to coarse grained, some gravel .. 18 . . . . . . -.... . . . . . . .. -. . . . . -.. . .
-45 -..... -8 ... fine grained, passing #200 = 35% . . SPT-7 ~ #200wash 14 . . . . . . 20 -.... -. . . . . .
. , .. ,-. . . . . .
,_ .. . . . . . .
50 -. ' .. --6 more silt ' ' -..... SPT-8 ¼ 18 . ' 10
,_
,_
Total Depth Drilled= 50' -Total Depth Sampled = 51.5' -55 --No Groundwater Encountered -Boring Backfilled with Soils Cuttings
-
-
-
60
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G-eo1:echnical -I'Vt:aterials Testing -Special Inspections
Geotechnical Boring Log B-2 (Previous Drilled)
Date: 7/6/2015 Page: 1 of 1
Project Name: SFR-Carlsbad at 4992 Project Number: 15-3071
Drilling Company: Discovery Type of Rig: CME-75
Drive Weight: 140Ibs Drop: 30" Hole Dia: 8"
Elevation of Top of Hole: -Hole Location: See Fiaure 2
..... c;::--DESCRIPTION Q) (.) ..a ..9: -0 g 0) E ~ ~ ..a en 0 :::I c ~ E Q)
C g _J z :::I (J) >-I-0 (.) Q) 0 C ~ U) 4-~ .c i= c.. u Q) :::I U) 0 0 -Logged By: DD > -c.. E ~ (J) u Q) c.. ro 2:-·o c.. Q) Q) ..... ro 0 U) >-w 0 (.9 U) CD 0 ~ => Sampled By: DD I-
0 l"iit CL TOR Soil -Sandy CLAY: brown, moist, very stiff Hi} c!!mt ---------1--~r------------------------------------------------------------------------------------------------------
H!>./:l\ R-1 111 14 Quaterna~ Old Alluvial Flood Plain DeRosits
(Qoa)
lt1iu -Sandy CLAY: brown, moist, hard
-5 -\I\ {ii*' I 14
:imi, Ai} R-2 15 112 13
19 .'!' ., . --------t--------------------------------------------------------------------------------------------------·
/;. .::::. I ML
·:·-· ·.• ::
R-3 7 111 7 Sandy SILT: light brown, moist, very stiff {>:/ >-12 HI
-10 .·::-:
I ·> ·_._ :-: 10 hard .:-:,: :• R-4 18 113 13
·.· .. ,.,,
-Total Depth Drilled= 10' -Total Depth Sampled = 11.5' -No Groundwater Encountered -15 --Boring Backfilled with Soils Cuttings --
---20 -------25 -------30 -
I .-.1c11.-.c:1 E .-.9 1.-.~~r1.-.9
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Geotechnical -IVl:aterials Testi.-.g -Special I.-.spectio.-.s
Geotechnical Boring Log 8-3
Date: 3/15/2018 Page: 1 of 1
Project Name: SFR-Carlsbad at 4984 Project Number: 16-3319
Drilling Company: Discovery Type of Rig: CME-75
Drive Weight: 140Ibs Drop: 30" Hole Dia: 8"
Elevation of Top of Hole: -Hole Location: See Ficiure 2
..... c;:::--DESCRIPTION Q) (.) .c s 0 g O'l E .......... .c --Z:-~ CJ) 0 ::i C ~ E Q)
C .......... _J z ::i ·u5 >, I-0 $ -~ 0 C Q) C/) '+--Q) ..... = ..c ..c a.. u Q) ::i C/) 0 ro 0 en Logged By: DD > -a. E ~ u Q) a. ro ~ ·o a. Q) Q) ..... ro 0 C/) >, w 0 (9 C/) CD 0 ~ :::::, Sampled By: DD I-
0 ,:tJ!i. CL To~ Soil
i<:"' ,,,.,,, -Sandy CLAY: light olive brown, moist.stiff 1.,;!;;,,,,,!ii;> El ,., ,,, ---------• --50-------------------------------------------------------------------------------------------------------
;ti} .. R-1 96 4 Quaterna!'.ll Old Alluvial Flood Plain De~osits Atterberg -(Qoa)
:1. ,)!; R-2 I 50 108 7 Sandy CLAY: light olive brown, moist, hard, Limits
-5 --trace of gravel, refusal
-
---Total Depth Drilled = 4'
Total Depth Sampled= 4' -10 --No Groundwater Encountered
,-Boring Backfilled with Soils Cuttings --.....
-15 --
-
-
-
-
-20 --
-
-
-
--25 --
-
--..... -30 -
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G-eot:echnical -1'11:at:erials Test:ing -Special Inspect:ions
'·
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8 -1
~ T. D. :,:,:.:51.:.:51
Inland Engineering
Technologies Inc. A. A/'\..___ ___ =-____ ,.r ~
Geotechnical • Materials Testing • Special Inspections
LEGEND
B-1
~
T.D . = 51 .5'
-Approximate Boring
Location & Total Depth
Total Depth Drilled = 51.5'
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, \>-:-··;-;
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t
t I
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FIGURE 2
BORING LOCATION MAP
4992 EUCALYPTUS LANE
CARLSBAD, CALIFORNIA
Project Name SFR -Carlsbad
Project No. 15-3071
En ineer YP
Scale Not To Scale
Date Au ust 2015
uo!le~o7 6upos aiew,xoJddv £-8 •
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pua6a7
APPENDIXC
LABORATORY TESTING PROCEDURES AND TEST RESULTS
APPENDIXC
Laboratory Testing Procedures and Test Results
The laboratory testing program was directed towards providing quantitative data relating to the relevant
engineering properties of the soils. Samples considered representative of site conditions were tested in general
accordance with American Society for Testing and Materials (ASTM) procedure and/or California Test Methods
(CTM), where applicable. The following summary is a brief outline of the test type and a table summarizing the
test results.
Soil Classification: Soils were classified according the Unified Soil Classification System (USCS) in accordance
with ASTM Test Methods D2487 and D2488. This system uses relies on the Atterberg Limits and grain size
distribution of a soil. The soil classifications ( or group symbol) are shown on the laboratory test data, and boring
logs.
Moisture and Density Determination Tests: Moisture content (ASTM D2216) and dry density determinations
(ASTM D2937) were performed on relatively undisturbed samples obtained from the test borings. The results of
these tests are presented in the boring logs. Where applicable, only moisture content was determined from
undisturbed or disturbed samples.
Grain Size Distribution: Representative samples were dried, weighed, and soaked in water until individual soil
particles were separated (per ASTM D421) and then washed on a No. 200 sieve. The percent passing #200 sieve
size is presented on the boring logs.
Atterberg Limits: The liquid and plastic limits ("Atterberg Limits") were determined in accordance with ASTM
D4 318 for engineering classification of fine-grained material and presented in the table below:
SAMPLE LIQUID LIMIT PLASTIC LIMIT PLASTICITY USCSSOIL
LOCATION INDEX CLASSIFICATION
B-1 @5' 36 27 9 CL
B-3 @5' 31 22 9 CL
Expansion Index: Expansion Index of selected samples was evaluated in accordance with ASTM D4829.
Specimens are molded under a given compactive energy to approximately the optimum moisture content and
approximately 50 percent saturation or approximately 90 percent relative compaction. The prepared I-inch-thick
by 4-inch-diameter specimens are loaded to an equivalent 144psf surcharge and are inundated with tap water until
volumetric equilibrium is reached. The results of these tests are presented in the table below:
SAMPLE SAMPLE EXPANSION EXPANSION
LOCATION DESCRIPTION INDEX POTENTIAL*
B-1, Bag-1 @0-5' Brown Sandy CLAY 73 Medium
B-3, Bag-1 @0-5' Brown Sandy CLAY 53 Medium
* Per ASTM D4829