HomeMy WebLinkAboutPD 2021-0004; NORTH COUNTY ACADEMY; GEOTECHNICAL INVESTIGATION -UPDATED REPORT; 2021-06-02
North County Academy 1640 Magnolia Avenue Carlsbad, CA 92008
Update Report
Geotechnical Investigation
North County Academy
Campus Consolidation
NOVA Project 2020187 June 2, 2021
4373 Viewridge Avenue, Suite B
San Diego, California 92123 858.292.7575 944 Calle Amanecer, Suite F San Clemente, CA 92673 P: 949.388.7710
www.usa-nova.com
-~ ~ ~~
Carlsbad
Unified School District
944 Calle Amanecer, Suite F San Clemente, CA 92673 P: 949.388.7710
4373 Viewridge Avenue, Suite B San Diego, CA 92123 P: 858.292.7575
www.usa-nova.com
DVBE SBE SDVOSB
Carlsbad Unified School District June 2, 2021
Derrick Anderson NOVA Project 2020187
6225 El Camino Real
Carlsbad, CA 92009
Subject: Update Report
Geotechnical Investigation
North County Academy, Campus Consolidation
1640 Magnolia Avenue, Carlsbad, California
Dear Mr. Anderson:
NOVA Services, Inc. (NOVA) is pleased to present herewith its update report of a geotechnical
investigation for the subject development. A report of the findings of the geotechnical
investigation was first submitted on December 7, 2020.
Grading Plans for this project were provided to NOVA in May 2021. The grading plan was
replaced as the base map for Plate 1 - Subsurface Map, and Plate 2 - Cross-Sections has been
added to the report now that proposed grades are known. In addition, since the previous
issuance of this report, NOVA has worked with the project Civil Engineer to calculate a site-
specific factor of safety using Form 1-9. Section 7 has been revised based on this change, and
Forms 1-8 and 1-9 have been revised/added.
NOVA appreciates the opportunity to be of continued service on this project. Should you have
any questions regarding this report or other matters, please contact the undersigned at
858.292.7575.
Sincerely,
NOVA Services, Inc.
_________________________ ________________________ Wail Mokhtar Melissa Stayner, PG, CEG Senior Project Manager Senior Engineering Geologist
_________________________ _________________________
John F. O’Brien, PE, GE Hillary A. Price Principal Geotechnical Engineer Senior Staff Geologist
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
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Update Report Geotechnical Investigation
North County Academy, Campus Consolidation 1640 Magnolia Avenue
Carlsbad, California
____________________________________________________________ Table of Contents
INTRODUCTION ................................................................................ 1
1.1 Terms of Reference ............................................................................................. 1
1.1 Update Report ...................................................................................................... 1
1.2 Objectives, Scope, and Limitations of Work ..................................................... 2
1.2.1 Objectives .................................................................................................................................. 2 1.2.2 Scope ........................................................................................................................................ 2 1.2.3 Limitations ................................................................................................................................. 3
1.3 Understood Use of This Report ......................................................................... 3
1.4 Report Organization ............................................................................................ 4
PROJECT INFORMATION ................................................................ 5
2.1 Location ............................................................................................................... 5
2.2 Site Description ................................................................................................... 5
2.2.1 Current Site Development ......................................................................................................... 5 2.2.2 Historic Site Use ........................................................................................................................ 6
2.3 Planned Development ......................................................................................... 6
2.3.1 General ...................................................................................................................................... 6 2.3.2 Structural ................................................................................................................................... 6
2.3.3 Civil ............................................................................................................................................ 6
SUBSURFACE EXPLORATION AND LABORATORY TESTING ..... 7
3.1 General ................................................................................................................. 7
3.2 Engineering Borings ........................................................................................... 8
3.2.1 General ...................................................................................................................................... 8
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3.2.2 Logging and Sampling .............................................................................................................. 8 3.2.3 Closure ...................................................................................................................................... 9
3.3 Percolation Testing ............................................................................................. 9 3.3.1 General ...................................................................................................................................... 9
3.3.2 Drilling ..................................................................................................................................... 10 3.3.3 Conversion to Percolation Well ............................................................................................... 10
3.3.4 Percolation Testing.................................................................................................................. 10 3.3.5 Closure .................................................................................................................................... 11
3.4 Geotechnical Laboratory Testing .................................................................... 11 3.4.1 General .................................................................................................................................... 11 3.4.2 Maximum Density and Optimum Moisture .............................................................................. 11 3.4.3 Soil Gradation .......................................................................................................................... 12 3.4.4 Expansion Potential ................................................................................................................ 12 3.4.5 R-Value ................................................................................................................................... 12 3.4.6 Chemical Testing..................................................................................................................... 13
SITE CONDITIONS .......................................................................... 14
4.1 Geologic Setting ................................................................................................ 14 4.1.1 Regional .................................................................................................................................. 14 4.1.2 Site Specific ............................................................................................................................. 14
4.2 Surface, Subsurface, and Groundwater .......................................................... 15
4.2.1 Surface .................................................................................................................................... 15
4.2.2 Subsurface .............................................................................................................................. 16 4.2.3 Groundwater ............................................................................................................................ 17
4.2.4 Surface Water ......................................................................................................................... 17
REVIEW OF GEOLOGIC, SOIL, AND SITING HAZARDS .............. 18
5.1 Overview ............................................................................................................ 18
5.2 Geologic Hazards .............................................................................................. 18
5.2.1 Strong Ground Motion ............................................................................................................. 18 5.2.2 Fault Rupture and Seismic Hazard ......................................................................................... 18 5.2.3 Historical Seismicity ................................................................................................................ 19 5.2.4 Landslide ................................................................................................................................. 19
5.3 Soil Hazards ....................................................................................................... 21
5.3.1 Embankment Stability ............................................................................................................. 21 5.3.2 Seismic .................................................................................................................................... 21
5.3.3 Expansive Soil ......................................................................................................................... 21 5.3.4 Hydro-Collapsible Soils ........................................................................................................... 22
5.3.5 Corrosive Soils ........................................................................................................................ 22
5.4 Siting Hazards ................................................................................................... 23
5.4.1 Effect on Adjacent Properties .................................................................................................. 23
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5.4.2 Flood ....................................................................................................................................... 23 5.4.3 Tsunami ................................................................................................................................... 23
5.4.4 Seiche ..................................................................................................................................... 24
EARTHWORK AND FOUNDATIONS .............................................. 25
6.1 Overview ............................................................................................................ 25
6.1.1 Review of Site Hazards ........................................................................................................... 25 6.1.2 Site Suitability .......................................................................................................................... 25
6.1.3 Review and Surveillance ......................................................................................................... 25
6.2 Seismic Design Parameters ............................................................................. 25
6.2.1 Site Class D ............................................................................................................................. 25
6.2.2 Seismic Design Parameters .................................................................................................... 26
6.3 Corrosivity and Sulfates ................................................................................... 26
6.3.1 General .................................................................................................................................... 26 6.3.2 Metals ...................................................................................................................................... 27 6.3.3 Sulfates and Concrete ............................................................................................................. 28 6.3.4 Limitations ............................................................................................................................... 28
6.4 Earthwork ........................................................................................................... 28
6.4.1 Standards for Earthwork ......................................................................................................... 28 6.4.2 Site Preparation....................................................................................................................... 29
6.4.3 Select Fill ................................................................................................................................. 29 6.4.4 Remedial Grading ................................................................................................................... 29
6.5 Foundations for the Modular Building, Walls and Handicapped Ramp ........ 30
6.5.1 Isolated and Continuous Foundations..................................................................................... 30 Conventional foundations, consisting of isolated and continuous footings, may be employed as described below. ..................................................................................................................................... 30 6.5.2 Resistance to Lateral Loads .................................................................................................... 30 6.5.3 Settlement ............................................................................................................................... 30 6.5.4 Ground Supported Slab .......................................................................................................... 30
6.6 Capillary Break and Underslab Vapor Retarder .............................................. 31 6.6.1 Capillary Break ........................................................................................................................ 31
6.6.2 Vapor Retarder ........................................................................................................................ 31
6.7 Walls ................................................................................................................... 32
6.7.1 Lateral Pressures .................................................................................................................... 32 6.7.2 Seismic Increment to Non-Yielding Site Walls ........................................................................ 33
6.8 Flatwork .............................................................................................................. 33
6.9 Miscellaneous Site Structures ......................................................................... 33
6.9.1 Signs and Light Poles ............................................................................................................. 33 6.9.2 Equipment Pads ...................................................................................................................... 34
6.9.3 Shade Structure ...................................................................................................................... 34
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6.10 Surfacing for the Play Area .............................................................................. 35
6.11 Trenching and Backfilling for Utilities ............................................................. 36
STORMWATER INFILTRATION ...................................................... 37
7.1 Overview ............................................................................................................ 37
7.2 Infiltration Rate .................................................................................................. 37
7.3 Review of Geotechnical Feasibility Criteria .................................................... 38 7.3.1 Overview ................................................................................................................................. 38 7.3.2 Soil and Geologic Conditions .................................................................................................. 38 7.3.3 Settlement and Volume Change ............................................................................................. 39 7.3.4 Slope Stability .......................................................................................................................... 39 7.3.5 Utilities ..................................................................................................................................... 39 7.3.6 Groundwater Mounding ........................................................................................................... 39 7.3.7 Retaining Walls and Foundations ........................................................................................... 39 7.3.8 Other ....................................................................................................................................... 39
7.4 Recommendation for Infiltration ...................................................................... 39
PAVEMENTS ................................................................................... 40
8.1 Overview ............................................................................................................ 40 8.1.1 General .................................................................................................................................... 40
8.1.2 Design to Limit Infiltration ........................................................................................................ 40 8.1.3 Maintenance ............................................................................................................................ 40
8.1.4 Review and Surveillance ......................................................................................................... 40
8.2 Subgrade Preparation ....................................................................................... 41
8.2.1 General .................................................................................................................................... 41 8.2.2 Proof-Rolling ............................................................................................................................ 41 8.2.3 Timely Base Course Construction ........................................................................................... 41
8.3 Flexible Pavements ........................................................................................... 41
8.4 Rigid Pavements ............................................................................................... 42
8.4.1 General .................................................................................................................................... 42 8.4.2 Joints ....................................................................................................................................... 42
REFERENCES ................................................................................. 43
9.1 Site Specific ....................................................................................................... 43
9.2 Design ................................................................................................................ 43
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9.3 Geologic and Site Setting ................................................................................. 44
Plates
Plate 1 Subsurface Exploration Map
Plate 2 Geologic Cross Sections AA’ & BB’
List of Appendices
Appendix A Use of the Geotechnical Report
Appendix B Logs of Borings
Appendix C Records of Laboratory Testing
Appendix D Infiltration Feasibility Documents
Appendix E Guide Specifications for Earthwork
List of Tables
Table 3-1. Abstract of the Engineering Borings
Table 3-2. Abstract of the Percolation Testing
Table 3-3. Abstract of the Moisture-Density Testing, ASTM D1557
Table 3-4. Abstract of the Soil Gradation Testing
Table 3-5. Abstract of Chemical Testing
Table 5-1. Summary of Expansion Index Testing
Table 6-1. Seismic Design Parameters, ASCE 7-16
Table 6-2. Summary of Corrosivity Testing of the Near Surface Soil
Table 6-3. Soil Resistivity and Corrosion Potential
Table 6-4. Exposure Categories and Requirements for Water-Soluble Sulfates ]\
Table 6-5. Wall Lateral Loads from Soil
Table 7-1. Infiltration Rates Determined by Percolation Testing
Table 8-1. Preliminary Recommendations for Flexible Pavements
Table 8-2. Recommended Concrete Requirements
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List of Figures
Figure 1-1. Vicinity Map
Figure 2-1. Site Location and Limits
Figure 3-1. Locations of Engineering and Percolation Test Borings
Figure 3-2. Drilling Operations November 3, 2020
Figure 3-3. Percolation Test Well P-2, November 4, 2020
Figure 4-1. Geologic Mapping of the Site Vicinity
Figure 4-2. Surface Conditions
Figure 4-3. Unit 2 Old Paralic Deposits
Figure 5-1. Faulting in the Site Vicinity
Figure 5-2. Landslide Susceptibility Mapping in the Site Area
Figure 5-3. Flood Mapping of the Site Area
Figure 6-1. Sawed Contraction Joint
Figure 6-2. Footing for a Shade Structure
Figure 6-3. Guy Cable Anchor
Figure 6-4. Layered Cushioning Media
Update Report, Geotechnical Investigation North County Academy, Campus Consolidation, Carlsbad, California NOVA Project 2020187
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INTRODUCTION
1.1 Terms of Reference
The work reported herein was completed by NOVA Services, Inc. (NOVA) for the Carlsbad
Unified School District (CUSD) for new portable classrooms on foundations, a shade structure,
and play structure proposed at the North County Academy, Carlsbad, California. The work
reported herein was completed in accordance with NOVA’s proposal dated October 12, 2020,
as authorized on that date.
North County Academy is located at 1640 Magnolia Avenue in Carlsbad. Figure 1-1 depicts the
vicinity of the school.
Figure 1-1. Vicinity Map
1.1 Update Report
NOVA provided an initial report of a geotechnical investigation of this site in a December 7,
2020 report (reference, Report, Geotechnical Investigation, Proposed Portable Classrooms,
North County Academy, 1640 Magnolia Avenue, Carlsbad, California, NOVA Project 2020187,
December 7, 2020 hereinafter, ‘NOVA 2020’).
At that time NOVA used architectural concepts as the basis of the proposed work. Since that
time, grading plans have been developed and incorporated into this report. The
recommendations of this report update and supersede those provided in NOVA 2020.
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Stormwater recommendations provided in Section 7 have now been revised to incorporate the
appropriate site-specific factor of safety.
1.2 Objectives, Scope, and Limitations of Work
1.2.1 Objectives
The objectives of the work reported herein are twofold, as described below.
• Geotechnical. Characterize subsurface conditions within the limits of the site in a
manner sufficient to develop recommendations for geotechnical-related
development, including foundations and earthwork.
• Stormwater. Develop percolation and subsurface information to provide design-stage
recommendations for development of stormwater infiltration Best Management
Practices (‘stormwater BMPs’).
1.2.2 Scope
NOVA undertook the task-based scope of work described below to address the above
objectives.
1. Task 1, Background Review. Reviewed background data, including geotechnical
reports, fault investigation reports and fault maps, topographic maps, geologic data,
and conceptual site plans for the project. No architectural, civil, or structural
information was available at the time of this work.
2. Task 2, Subsurface Exploration. A NOVA geologist directed a subsurface exploration
that included the subtasks listed below.
• Subtask 2-1, Reconnaissance. Prior to undertaking any exploratory work,
NOVA conducted a site reconnaissance, including layout of engineering
borings used to explore the subsurface conditions. Underground Service Alert
and a utility location contractor were notified for underground utility mark-out
services.
• Subtask 2-2, Coordination. NOVA retained a specialty a subcontractor to
conduct the drilling. NOVA coordinated with CUSD regarding access for
fieldwork.
• Subtask 2-3, Engineering Borings. Four (4) engineering borings were drilled
to depths up to 21.5 feet in depth using a truck-mounted hollow-stem drill rig.
The borings were sampled using ASTM methods.
• Subtask 2-4, Percolation Testing. NOVA coordinated with Alpha Studio
Design Group (ASDG) for stormwater BMP locations. Two (2) infiltration tests
wells were installed and tested within the area of the proposed BMP. Each
test well extended 5 feet below ground surface. Thereafter, percolation
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testing was conducted in accordance with the requirements of the City of
Carlsbad.
3. Task 3, Laboratory Testing. Laboratory testing addressed pertinent index soil
characteristics as well as testing to determine design parameters for flexible
pavements. Chemical testing addresses the potential that soils may be corrosive to
embedded concrete or metals.
4. Task 4, Engineering Evaluations. The findings of Tasks 1 through 3 were utilized to
support evaluations directed toward (i) recommendations for geotechnical-related
development, including foundations for buildings, playground equipment, and
earthwork; and, (ii) determination of design requirements for stormwater infiltration
BMPs.
5. Task 5, Reporting. Submittal of his report completes NOVA’s scope of work. Report
includes a record of all work and provides recommendations for foundation design,
pavement design, design for permanent stormwater infiltration BMPs, and earthwork.
1.2.3 Limitations
Assessment of the subsurface in geological and geotechnical engineering is characterized by
uncertainty. Opinions relating to environmental, geologic, and geotechnical conditions are based
on limited data, such that actual conditions may vary from those encountered at the times and
locations where the data are obtained, despite the use of due professional care. The judgments
provided in this report are based upon NOVA’s understanding of the planned construction, its
experience with similar work, and its judgments regarding subsurface conditions indicated by
subsurface exploration described in the report.
This report addresses geotechnical considerations only. The report does not provide any
environmental assessment or investigation of the presence or absence of hazardous or toxic
materials in the soil, soil gas, groundwater, or surface water within or beyond the site.
Appendix A provides important additional guidance regarding the use and limitations of this
report. This information should be reviewed by all users of the report.
1.3 Understood Use of This Report
NOVA expects that the recommendations provided herein will be utilized by CUSD and its
Design Team in decision-making regarding design and construction. The recommendations are
based on NOVA’s current understanding and assumptions regarding project development.
Effective use of this report should include review of the final design by NOVA. Such review is
important for both (i) conformance with the recommendations provided herein, and (ii)
consistency with NOVA’s understanding of the planned development.
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1.4 Report Organization
The remainder of this report is organized as described below.
• Section 2 reviews the presently available project information.
• Section 3 describes the field investigation and laboratory testing.
• Section 4 describes the geologic and subsurface conditions.
• Section 5 reviews geologic and soil hazards common to development of civil works in
this region, considering each for its potential to affect this site.
• Section 6 provides recommendations for earthwork and foundations.
• Section 7 addresses stormwater infiltration.
• Section 8 provides recommendations for pavement design and construction.
• Section 9 lists the principal references used in the development of this report.
Figures and tables that amplify the discussions in the text are embedded therein. Larger scale
plates that show the location of subsurface exploration and subsurface conditions are provided
immediately following the text of the report. The report is supported by five appendices.
• Appendix A presents guidance regarding the use and limitations of this report.
• Appendix B provides logs of the engineering borings.
• Appendix C provides records of the geotechnical laboratory testing.
• Appendix D provides records related to development of stormwater infiltration criteria.
• Appendix E provides guide specifications for earthwork.
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PROJECT INFORMATION
2.1 Location
The approximately 0.25-acre site of investigation is nominally located at 1640 Magnolia Avenue
in Carlsbad, California (APN 205-220-99-00, hereinafter also referenced as ‘the site’). It is part
of the larger North County Academy campus.
The school is bounded on the north and west by Brady Circle. Residential development bounds
the site to the east, and Magnolia Avenue bounds the property to the south. Figure 2-1 depicts
these limits on a recent aerial image.
Figure 2-1. Site Location and Limits (source: adapted from Google Earth 2016)
2.2 Site Description
2.2.1 Current Site Development
The site currently serves as an undeveloped grass play field. The site is relatively flat. Ground
elevations range from about +158 feet mean sea level (msl) in the southwest corner to about
+163 feet msl along the eastern boundary.
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2.2.2 Historic Site Use
A review of historic aerial photos shows that the site had been used for agriculture until about
2002, when the existing school was constructed.
2.3 Planned Development
2.3.1 General
NOVA’s understanding of the planned development is based upon review of concept planning
developed by Alpha Studio Design Group (reference, North County Academy: Option 1, Alpha
Studio Design Group, provided to NOVA October 2020, hereinafter ‘ASDG 2020’).
Associated with review of this concept planning, NOVA has been provided with grading plans
for the project (reference, Grading Plans for: North County Academy, Campus Consolidation,
Pasco Laret Suitor & Associates, Project No. PD 2021-004, plotted May 10, 2021, hereinafter
‘PLSA 2021’).
ASDG 2020 depicts planning for three modular classrooms on concrete foundations, playground
equipment, a shade structure, and a stormwater BMP facility.
2.3.2 Structural
No structural information is yet available. Based upon review of ASDG 2020, NOVA expects
that the new modular classrooms will be light.
2.3.3 Civil
Design finished grades in the area of the proposed modules and the play areas will be adapted
to the existing ground form, limiting demand for earthwork. Earthwork will likely be limited to
development of stormwater infiltration Best Management Practices (BMPs) as well as
installation of appurtenant wet and dry utilities. PLSA 2021 estimates 825 CY of cut and 75 CY
of fill. Net export is anticipated to be 750 CY.
Recommendations for earthwork are discussed in detail in Section 6.
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SUBSURFACE EXPLORATION AND LABORATORY TESTING
3.1 General
NOVA’s subsurface exploration included four (4) engineering borings (referenced as ‘B-1’
through ‘B-4’) and two (2) planning phase percolation test borings (‘P-1’ through ‘P-2’).
The borings were completed by a specialty subcontractor retained by NOVA working under the
continuous supervision of a NOVA geologist. Figure 3-1 presents a plan view of the site which
indicates the location of the engineering and percolation test borings. Plate 1, provided
immediately following the text of this report, shows the location of this work in larger scale.
Figure 3-1. Locations of Engineering and Percolation Test Borings
Soil samples recovered from the engineering borings were returned to NOVA’s materials
laboratory for visual inspection and testing. The remainder of this section describes the
subsurface exploration and related laboratory testing.
3.0
KEY TO SYMBOLS
Qop
B-4
8
P-2
EB
/'J
OLD PARALIC DEPOSITS
GEOTECHNICAL SORING
PERCOLATION TEST BORING
SITE LIMITS I LIMITS
OF INVESTIGATION
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3.2 Engineering Borings
3.2.1 General
A NOVA geologist directed drilling and sampling of four (4) hollow-stem auger borings to depths
of 16.5 feet to 21.5 feet below ground surface (bgs) on November 3, 2020. The borings were
drilled under the surveillance of a NOVA geologist.
The engineering borings were advanced by a truck-mounted drilling rig utilizing hollow-stem
auger drilling equipment. Boring locations were determined in the field by the geologist at the
locations shown on Figure 3-1. Table 3-1 provides an abstract of the engineering borings.
Table 3-1. Abstract of the Engineering Borings
Boring Reference
Approx. Ground Surface Elev. (feet, msl)
Total Depth Below Ground Surface (feet)
Elevation at Completion (feet, msl)
Approx. Depth to Formation (feet) 1
Approx. Depth to Groundwater (feet)
B-1 +162 16.5
+145.5 1.0 Not Encountered
B-2 +160 21.5
+138.5 1.0 Not Encountered
B-3 +163 21.5 +141.5 1.0 Not Encountered
B-4 +162 21.5 +140.5 1.0 Not Encountered
Note 1: the referenced geologic unit is the Quaternary Old Paralic Deposits (Qop)
Figure 3-2 (following page) depicts field operations on November 3, 2020.
3.2.2 Logging and Sampling
The NOVA geologist directed sampling and maintained a log of the subsurface materials that
were encountered. Both disturbed and relatively undisturbed samples were recovered from the
borings, sampling of soils is described below.
1. The Modified California sampler (‘ring sampler’, after ASTM D 3550) was driven using a
140-pound hammer falling for 30 inches with a total penetration of 18 inches, recording
blow counts for each 6 inches of penetration.
2. The Standard Penetration Test sampler (‘SPT’, after ASTM D1586) was driven in the
same manner as the ring sampler, recording blow counts in the same fashion. SPT blow
counts for the final 12 inches of penetration comprise the SPT ‘N’ value, an index of soil
consistency.
3. Bulk samples were collected, providing composite samples for testing of soil moisture
and density relationships, soil index testing, and corrosivity.
Logs of the engineering borings are provided in Appendix B. The stratification lines designating
the interfaces between earth materials on the boring logs and profiles are approximate; in-situ,
the transitions may be gradual.
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Figure 3-2. Drilling Operations November 3, 2020
3.2.3 Closure
On completion, the borings were backfilled with soil cuttings. The area of each boring was
cleaned and left as close as practical to its original condition.
3.3 Percolation Testing
3.3.1 General
NOVA directed the excavation and construction of two (2) percolation test wells within 50 feet of
the proposed biofiltration basin following the recommendations for percolation testing presented
in the City of Carlsbad BMP Design Manual, 2016 edition. An exploratory boring was excavated
extending at least 10 feet below the proposed basin. In accordance with this manual,
percolation rates were later converted to infiltration rates. Detailed discussion of infiltration rates
and recommendations are presented in Section 7. The percolation test locations are shown on
Figure 3-1.
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3.3.2 Drilling
The borings for the wells were drilled with an 8-inch hollow stem auger to a depth of 5 feet bgs,
to the bottom of the proposed basin. Field measurements were taken to confirm that the borings
were excavated to approximately 8 inches in diameter. The borings were logged by a NOVA
geologist, who observed and recorded exposed soil cuttings and the boring conditions.
3.3.3 Conversion to Percolation Well
Once the borings were drilled to the desired depths, the borings were converted to percolation
test wells by placing an approximately 2-inch layer of ¾-inch gravel on the bottom, then
extending 3-inch diameter Schedule 40 perforated PVC pipe to the ground surface. The ¾-inch
gravel was used to partially fill the annular space around the perforated pipe below the existing
finished grade to minimize the potential of soil caving. Figure 3-3 depicts the completed
construction of a percolation test well.
Figure 3-3. Percolation Test Well P-2, November 4, 2020
3.3.4 Percolation Testing
The percolation test wells were pre-soaked by filling the well with water to at least five times the
well’s radius. In each test well, the pre-soak water did not percolate at least 6 inches into the soil
unit within 25 minutes; therefore, the hole was filled to the ground surface elevation and testing
commenced the following day, within a 26-hour window.
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Water levels were then recorded every 30 minutes for 6 hours (minimum of 12 readings), or until
the water percolation stabilized after each reading. Prior to each 30-minute test interval, the
water level was raised to approximately the same level as the previous 30-minute test interval in
order to maintain a near-constant head for each reading.
Table 3-2 summarizes the results of the percolation testing.
Table 3-2. Abstract of the Percolation Testing
Boring Reference Elevation (feet, msl) 1
Total Depth (feet)
Percolation Test Elevation (feet, msl) 1
Percolation Rate (min/in) 2
Subsurface Unit Tested3
Infiltration Rate (in/hr) 2
Infiltration Rate (in/hr,
FS=3.375)4
P-1 +162 5 +157 83 Qop 0.03 0.009 P-2 +163 5 +158 50 Qop 0.06 0.018
Note 1: Elevations are approximate and should be reviewed. Note 2: Percolation rate is not infiltration rate. Infiltration rates are discussed in detail in Section 7. Note 3: The referenced geologic subsurface unit tested is Quaternary Old Paralic Deposits (Qop). Note 4: ‘FS’ indicates ‘Factor of Safety’. FS is discussed further in Section 7.
3.3.5 Closure
At the conclusion of the percolation testing, the PVC pipes were removed and the resulting
holes were backfilled with soil cuttings.
3.4 Geotechnical Laboratory Testing
3.4.1 General
Soil samples recovered from the borings were returned to the laboratory where an engineering
geologist reviewed the field logs and classified each soil sample on the basis of texture and
plasticity in accordance with the Unified Soil Classification System (‘USCS,’ ASTM D 2487).
Representative soil samples were selected and tested in NOVA’s materials laboratory to check
visual classifications and to determine pertinent engineering properties. The laboratory testing
program included index and strength testing on selected soil samples. Testing was performed in
general accordance with ASTM standards. Records of the laboratory testing are presented in
Appendix C.
3.4.2 Maximum Density and Optimum Moisture
Two (2) tests after ASTM D1557 (the ‘modified Proctor) were undertaken to determine the
moisture density relationship of the near-surface soils. This testing provides an indication of the
behavior of the soil as a construction material. Table 3-3 (following page) provides an abstract
of this testing.
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Table 3-3. Abstract of the Moisture-Density Testing, ASTM D1557
Boring Depth (feet) Soil Description Maximum Dry Density Optimum Moisture Content (%)
B-1 2 – 5 Orange Brown Silty Sand 135.1 8.1
B-2 1 – 5 Orange Brown Silty Sand/Clayey Sand 132.5 7.9
3.4.3 Soil Gradation
The visual classifications were further evaluated by performing grain size testing. Gradation
testing was performed after ASTM D422. Table 3-4 provides a summary of this testing.
Table 3-4. Abstract of the Soil Gradation Testing
Sample Reference Percent Finer
than the U.S. No 200 Sieve
Classification
after ASTM D2488 Boring Depth (feet)
B-1 2 – 5 35 SM
B-1 5 47 SM
B-1 7 – 10 44 SM
B-1 7.5 31 SM
B-1 10 26 SC
B-3 2.5 40 SM
B-3 5 55 SM/ML
B-3 7.5 29 SM
B-3 10 26 SM
B-3 15 22 SM
B-3 20 15 SM
Note: ‘Passing #200’ percent by weight passing the U.S. # 200 sieve (0.074 mm), after ASTM D6913. 3.4.4 Expansion Potential
A representative sample of the near-surface soil was tested to determine expansion index (EI),
after ASTM D4829. The sample indicated EI = 1; characteristic of a soil with Very Low
expansion potential.
3.4.5 R-Value
The Resistance Value (R-value) test is a material stiffness test, demonstrating a material’s
resistance to deformation as a function of the ratio of transmitted lateral pressure to applied
vertical pressure.
The purpose of this test is to determine the suitability of prospective subgrade soils and road
aggregates for use in the pavement sections of roadways. The test is used by Caltrans for
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pavement design, replacing the California Bearing Ratio (CBR) test. A saturated cylindrical soil
sample is placed in a Hveem Stabilometer device and then compressed. The stabilometer
measures the horizontal pressure that is produced while the specimen is under compression.
A sample representative of soils from the near-surface was selected for this testing. Testing
after ASTM D2844 indicated an R-value of 38.
3.4.6 Chemical Testing
Resistivity, sulfate content and chloride contents were determined to estimate the potential
corrosivity of the soils. These chemical tests were performed on a representative sample of the
near-surface soils.
Table 3-5 abstracts chemical testing. Indications of this testing are discussed in more detail in
Section 6.3.
Table 3-5. Abstract of Chemical Testing
Sample Reference pH Resistivity (Ohm-cm)
Sulfates Chlorides
Boring Depth (feet) ppm % ppm %
B-1 2 – 5 8.6 3300 39 0.004 32 0.003
I I
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SITE CONDITIONS
4.1 Geologic Setting
4.1.1 Regional
The project area is located in the coastal portion of the Peninsular Ranges geomorphic
province. This geomorphic province encompasses an area that extends approximately 900
miles from the Transverse Ranges and the Los Angeles Basin south to the southern tip of Baja
California. The province varies in width from approximately 30 to 100 miles.
The province is characterized by northwest trending ranges separated by valleys. Major active
fault systems include from east to west, San Andreas, San Jacinto, Elsinore, and Rose Canyon
fault zones.
The coastal portion of the Province where the site is located has undergone several episodes of
marine inundation and subsequent marine regression (coastline changes) throughout the last 54
million years. These events have resulted in the deposition of a thick sequence of marine and
nonmarine sedimentary rocks on the basement igneous rocks of the Southern California
Batholith and metamorphic rocks.
Gradual emergence of the region from the sea occurred in Pleistocene time, and numerous
wave-cut platforms, most of which were covered by relatively thin marine and nonmarine terrace
deposits, formed as the sea receded from the land. Accelerated fluvial erosion during periods of
heavy rainfall, along with the lowering of base sea level during Quaternary times, resulted in the
rolling hills, mesas, and deeply incised canyons that characterize the landforms in western San
Diego County.
4.1.2 Site Specific
The site area is underlain by nonmarine and near-shore marine sedimentary rocks deposited at
various intervals from the Tertiary through Quaternary periods. The site is mapped on
Quaternary terrace deposits, referred to as old paralic deposits (Qop2-4). These late to middle
Pleistocene-aged deposits consist mainly of interfingered strandline, beach, estuarine, and
colluvial deposits composed of siltstone, sandstone, and conglomerate. The differently
numbered terraces designate different ages and elevations of marine abrasion platforms.
Geologic units encountered by NOVA’s subsurface investigation include a thin veneer of topsoil
overlying silty and clayey sandstones of the old paralic deposits.
The old paralic deposits are competent as a foundation material, being relatively high strength
and low compressibility. Many of the monumental civil structures in San Diego County are founded on these sedimentary units.
Figure 4-1 (following page) reproduces geologic mapping of the site area.
4.0
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Figure 4-1. Geologic Mapping of the Site Vicinity
4.2 Surface, Subsurface, and Groundwater
4.2.1 Surface
The site is currently a vacant, graded, and grassed pad. Elevations across the relatively level
site area range from ± 164 feet mean sea level (msl) at the northeast corner to +162 feet msl at
the southeast. This 2-foot differential occurs over a distance of 150 feet, a surface gradient of
about 1.5%.
Figure 4-2 (following page) depicts surface conditions.
KEY TO SYMBOLS
I aop5_71 OLD PARALIC DEPOSITS, I Qvop13 I VERY OLD PARALIC ~ SANTIAGO FORMATION UNIT 6-7, UNDIVIDED DEPOSITS, UNIT 13
I aop2-4 I OLD PARALIC DEPOSITS, I 0VOP12 I VERY OLD PARALIC ~ ALLUVIAL FLOOD-PLAIN
UNIT 2-4, UNDIVIDED DEPOSITS, UNIT 12 DEPOSITS
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Figure 4-2. Surface Conditions
4.2.2 Subsurface
The sequence of subsurface materials encountered by the borings may be generalized to occur
as described below.
1. Unit 1, Topsoil. The site is covered by a thin veneer of topsoil about 1-foot thick. The
topsoil is comprised of dark brown to orange-brown, fine to coarse-grained silty sand.
This soil may be derived from previous agricultural use or serve as landscaping for the
current playfield.
2. Unit 2, Quaternary Old Paralic Deposits (Qop). The topsoil is underlain by old paralic
deposits. As encountered in the borings, the unit is characteristically orange-brown to
dark orange-brown, medium dense to dense in consistency, and composed of layers of
silty and clayey sandstone.
As encountered in the borings, the unit is characterized by SPT blow counts (‘N’, after
ASTM D1586) of N = 18 to N = 55 blows/foot. As a foundation unit for the planned
modules, the paralic deposits can be expected to be of high strength and low
compressibility.
The paralic deposits extend well beyond the maximum depth explored during this
investigation.
Figure 4-3 (following page) depicts this unit.
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Figure 4-3. Unit 2 Old Paralic Deposits
4.2.3 Groundwater
Groundwater was not encountered in the borings, though near the bottom of the borings, the
material became wet. During background review, there were no nearby well data to estimate
groundwater level at the site. Based on borings performed for this investigation, groundwater
will not be a constraint to development.
4.2.4 Surface Water
No surface water was evident on the site at the time of NOVA’s work. At the time of NOVA’s
subsurface exploration, there were no evident signs of recent problems with surface water (i.e.,
no evidence of staining, erosion, seeps, springs, etc.).
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REVIEW OF GEOLOGIC, SOIL, AND SITING HAZARDS
5.1 Overview
This section provides review of geologic and soil-related hazards common to this region of
California, considering each for its potential to affect the planned development.
Based upon the review described in this section, the principal hazard identified by this review is
that the site is at risk for moderate-to-severe ground shaking in response to a large-magnitude
earthquake during the lifetime of the planned improvements to North County Academy. This
circumstance is common to all civil works in this area of California. Section 6.2 addresses
seismic design parameters.
While the site is at risk for strong ground motion in the event of an earthquake, there is no risk of
liquefaction or related seismic phenomena.
The following subsections address NOVA’s review of potential site hazards.
5.2 Geologic Hazards
5.2.1 Strong Ground Motion
The seismicity of the site was evaluated utilizing a web-based analytical tool provided by
OSHPD and Structural Engineers Association of California (SEAOC). This evaluation shows the
site may be subjected to a Magnitude 7 seismic event, with a corresponding site-modified Peak
Ground Acceleration (PGAM) of PGAM ~ 0.522g.
5.2.2 Fault Rupture and Seismic Hazard
The site is not located within a designated Alquist-Priolo earthquake fault hazard zone, and no
surface evidence of faulting was observed during NOVA’s geologic reconnaissance of the site.
The nearest mapped active faults are offshore, within the Newport-Inglewood-Rose Canyon
fault zone (Oceanside section), about 5.3 miles to the west.
Figure 5-1 (following page) maps faulting in the site vicinity.
Because of the lack of known active faults on the site, the potential for surface rupture at the site
is considered low. Shallow ground rupture due to shaking from distant seismic events is not
considered a significant hazard, although it is a possibility at any site.
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Figure 5-1. Faulting in the Site Vicinity
5.2.3 Historical Seismicity
No historical seismic event has been located in the vicinity of Carlsbad, California. The closest historical events to the site were:
• Magnitude 6.0 Elsinore Earthquake on May 15, 1910, located 41 miles northwest of the site; and
• Magnitude 6.4 Long Beach Earthquake on March 10, 1932, which was locate 46 miles northwest.
Damage from these earthquakes was not reported in Carlsbad (SCEDC).
5.2.4 Landslide
As used herein, ‘landslide’ describes downslope displacement of a mass of rock, soil, and/or
debris by sliding, flowing, or falling. Such mass earth movements are greater than about 10 feet
thick and larger than 300 feet across. Landslides typically include cohesive block glides and
disrupted slumps that are formed by translation or rotation of the slope materials along one or
more slip surfaces. These mass displacements can also include similarly larger-scale, but more
narrowly confined modes of mass wasting such as rock topples, ‘mud flows,’ and ‘debris flows’.
KEY TO SYMBOLS
ACTIVE WITHIN 150 YEARS
ACTIVE <15,000 YEARS
LATE QUATERNARY <130,000 YEARS
Pacific Ocean
NEWPORT-INGLEWOOD-ROSE
CANYON FAULT ZONE
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The causes of classic landslides start with a preexisting condition - characteristically, a plane of
weak soil or rock - inherent within the rock or soil mass. Thereafter, movement may be
precipitated by earthquakes, wet weather, and changes to the structure or loading conditions on
a slope (e.g., by erosion, cutting, filling, release of water from broken pipes, etc.). Rainfall and
earthquakes are the most common triggers for landslide events. Landsliding may also be
precipitated by a larger-scale earthwork, by destabilizing slopes when cutting and/or filling on
existing adverse geologic structure.
Clues to the landslide hazard for an area can be obtained by review of mapping that depicts
both historic landslides and landslide-prone geology/topography. Figure 5-2 reproduces such
mapping, from which it can be seen that the school is located in an area of favorable geologic
structure, with little risk of landsliding.
Figure 5-2. Landslide Susceptibility Mapping in the Site Area
In consideration of the generally flat topography of the site and surrounding area, and the flat-
lying geologic structure of the bedrock, it is the judgment of NOVA that the site in its current
condition is not at risk for landsliding.
KEY TO SYMBOLS
RELATIVE LANDSLIDE SUSCEPTIBILITY AREAS LANDSLIDES
L&ndslcJtt
Ouesllonable l.ai,dslide
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5.3 Soil Hazards
5.3.1 Embankment Stability
As used herein, ‘embankment stability’ is intended to mean the safety of localized natural or
man-made embankments against failure. Unlike landslides described above, embankment
stability can include smaller-scale slope failures such as erosion-related washouts and more
subtle, less evident processes such as soil creep.
North County Academy is located in a relatively flat-lying area. The site itself is developed with
no embankments taller than a few feet. No embankments are anticipated with the planned
development. In consideration of these factors, it is the judgment of NOVA that the risk of site
damaged by embankment instability is negligible.
5.3.2 Seismic
Liquefaction
‘Liquefaction’ refers to the loss of soil strength during a seismic event. The
phenomenon is observed in areas that include geologically ‘younger’ soils (i.e., soils
of Holocene age), shallow water table (less than about 60 feet depth), and
cohesionless (i.e., sandy and silty) soils of looser consistency. The seismic ground
motions increase soil water pressures, decreasing grain-to-grain contact among the
soil particles, which causes the soils to lose strength.
Resistance of a soil mass to liquefaction increases with increasing density, plasticity
(associated with clay-sized particles), geologic age, cementation, and stress history.
In consideration of the combination of the dense consistency and the geologic age of
the subsurface paralic deposits, and the depth to groundwater, NOVA considers the
liquefaction potential of this site to be low.
Seismically Induced Settlement
Apart from liquefaction, a strong seismic event can induce settlement within loose to
moderately dense, unsaturated granular soils. The sandstones and cemented sands
of the paralic deposits are sufficiently dense that these soils will not be prone to
seismic settlement.
Lateral Spreading
Due to the absence of a potential for liquefaction, there is no potential for
liquefaction-related lateral spreading.
5.3.3 Expansive Soil
Expansive soils are clays characterized by their ability to undergo significant volume changes
(shrinking or swelling) due to variations in moisture content, the magnitude of which is related to
both clay content and plasticity index. These volume changes can be damaging to structures.
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Nationally, the value of property damage caused by expansive soils is exceeded only by that
caused by termites.
As is discussed in Section 3, the Unit 1 and 2 soils have been characterized by testing to
determine Expansion Index (‘EI’, after ASTM D 4829). EI has been adopted by the California
Building Code (‘CBC’, Section 1803.5.3) for characterization of expansive soils. The listing
below tabulates the qualitative descriptors of expansion potential based upon EI.
Table 5-1. Summary of Expansion Index Testing
Expansion Index (‘EI’), ASTM D 4829 Expansion Potential, ASTM D 4829 Expansion Classification, 2013 CBC
0 to 20 Very Low Non-Expansive
21 to 50 Low
Expansive 51 to 90 Medium
91 to 130 High
>130 Very high
Neither the Unit 1 topsoil nor the Unit 2 old paralic deposits are expansive.
5.3.4 Hydro-Collapsible Soils
Hydro-collapsible soils are common in the arid climates of the western United States in specific
depositional environments - principally, in areas of young alluvial fans, debris flow sediments,
and loess (wind-blown sediment) deposits. These soils are characterized by low in situ density,
low moisture contents, and relatively high unwetted strength. The soil grains of hydro-collapsible
soils were initially deposited in a loose state (i.e., high initial ‘void ratio’) and thereafter lightly
bonded by water sensitive binding agents (e.g., clay particles, low-grade cementation, etc.).
While relatively strong in a dry state, the introduction of water into these soils causes the binding
agents to fail. Destruction of the bonds/binding causes relatively rapid densification and volume
loss (collapse) of the soil. This change is manifested at the ground surface as subsidence or
settlement. Ground settlements from the wetting can be damaging to structures and civil works.
Human activities that can facilitate soil collapse include irrigation, water impoundment, changes
to the natural drainage, disposal of wastewater, etc.
The consistency of Unit 1 topsoil and the consistency and geologic age of Unit 2 paralic
sandstone deposits are such that these units are not potentially hydro-collapsible.
5.3.5 Corrosive Soils
Chemical testing of the near-surface soils indicates the soils contain low concentrations of
soluble sulfates and chlorides, but low resistivity measurements, suggesting these soils will not
be corrosive to embedded concrete, but may be considered moderately corrosive to buried
metals based on the resistivity value. Section 6 addresses this consideration in more detail.
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5.4 Siting Hazards
5.4.1 Effect on Adjacent Properties
Development of the proposed school will not affect the structural integrity of adjacent properties
or existing public improvements and street right-of-ways located adjacent to the site if the
recommendations of this report are incorporated into project design.
5.4.2 Flood
The site is not located within a FEMA-designated flood zone. Review of FEMA mapping shows
the site area is designated “Zone X,” an ‘area of minimal flood hazard.’ Figure 5-3 reproduces
flood mapping by FEMA of the site area.
Figure 5-3. Flood Mapping of the Site Area (source: FEMA Flood Map 06073C0762G, 5/16/2012)
5.4.3 Tsunami
Tsunami describes a series of fast-moving, long-period ocean waves caused by earthquakes or
volcanic eruptions. Based on the elevation and distance of the site from the ocean, tsunamis are
not a hazard to this site.
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5.4.4 Seiche
Seiches are standing waves that develop in an enclosed or partially enclosed body of water
such as lakes or reservoirs. Harbors or inlets can also develop seiches. Most commonly caused
by strong winds and rapid atmospheric pressure changes, seiches can be affected by seismic
events and tsunamis.
The site is not located near a body of water that could generate a seiche.
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EARTHWORK AND FOUNDATIONS
6.1 Overview
6.1.1 Review of Site Hazards
Section 5 provides a review of soil, geologic, and siting hazards common to development of civil
works in the project area. The primary hazard identified by that review is that the site is at risk
for moderate-to-severe ground shaking in response to a large-magnitude earthquake during the
lifetime of the planned development. This circumstance is common to all civil works in this area
of California.
While strong ground motion could affect the site, there is no risk of liquefaction or related
seismic phenomena. Section 6.2 provides seismic design parameters.
6.1.2 Site Suitability
Based upon the indications of the subsurface and laboratory data developed for this
investigation, it is the opinion of NOVA that the site is suitable for the planned development,
provided the geotechnical recommendations described herein are followed.
Development of the proposed school will not affect the structural integrity of adjacent properties
or existing public improvements and street right-of-ways located adjacent to the site if the
recommendations of this report are incorporated into project design.
6.1.3 Review and Surveillance
The subsections following provide geotechnical recommendations for the planned development
as it is now understood. It is intended that these recommendations provide sufficient
geotechnical information to develop the project in general accordance with 2019 California
Building Code (CBC) requirements.
NOVA should be given the opportunity to review the grading plan, foundation plan, and
geotechnical-related specifications as they become available to confirm that the
recommendations presented in this report have been incorporated into the plans prepared for
the project. All earthwork related to site and foundation preparation should be completed under
the observation of NOVA.
6.2 Seismic Design Parameters
6.2.1 Site Class D
The site-specific data used to determine the Site Class typically includes borings drilled to 100
feet in depth to correlate Standard Penetration resistances (N-values) to Site Class per ASCE 7-
16 (Table 20.3-1). The depth of soil information available for this site is limited. However, as is
discussed in Section 4, the site is underlain by a sequence of sedimentary deposits that extend
to great depth.
6.0
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NOVA has a lot of experience with the old paralic deposits along the coastal portions of San
Diego County, therefore, based on blow counts encountered at the site, and shear wave
analyses NOVA has previously performed in nearby areas within this geologic unit, the site is
classified as Site Class D.
6.2.2 Seismic Design Parameters
Due to the size of the proposed modular building and improvements planned for this project,
NOVA assumes that Exception 2 of ASCE 7-16, Chapter 11.4.8 applies to this project, and a
site-specific ground motion analysis is not required.
The long-period site coefficient, FV, was taken from Table 11.4-2, and SM1 and SD1 were
calculated from Equations 11.4-2 and 11.4-4. Table 6-1 provides seismic design parameters for
the site in accordance with 2019 CBC. Note that these parameters assume the school
structures are Risk Category III.
Table 6-1. Seismic Design Parameters, ASCE 7-16
Parameter Value
Soil Class D
Risk Category III
Site Latitude (decimal degrees) 33.15911
Site Longitude (decimal degrees) -117.32944
Site Coefficient, Fa 1.085
Site Coefficient, Fv 1.924
Mapped Short Period Spectral Acceleration, SS 1.038
Mapped One-Second Period Spectral Acceleration, S1 0.377
Short Period Spectral Acceleration Adjusted For Site Class, SMS 1.125
One-Second Period Spectral Acceleration Adjusted For Site Class, SM1 0.723
Design Short Period Spectral Acceleration, SDS 0.750
Design One-Second Period Spectral Acceleration, SD1 0.482
Site Adjusted Peak Ground Acceleration (PGAM) 0.522
Source: OSHPD Seismic Design Maps, found at www.seismicmaps.org; Value of Fv was interpolated from ASCE 7-16 Table 11.4-2.
6.3 Corrosivity and Sulfates
6.3.1 General
Electrical resistivity, chloride content, and pH level are all indicators of the soil’s tendency to
corrode ferrous metals. Levels of water-soluble sulfates are used as an index of the potential for
sulfate attack to concrete.
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These chemical tests were performed on a representative sample of the near-surface soils.
Records of this testing are provided in Appendix C. The results of the testing are tabulated on
Table 6-2.
Table 6-2. Summary of Corrosivity Testing of the Near Surface Soil
Parameter Units Value
pH standard unit 8.6
Resistivity Ohm-cm 3300
Water-Soluble Chloride ppm 32
Water Soluble Sulfate ppm 39
6.3.2 Metals
Caltrans considers a soil to be corrosive if one or more of the conditions listed below exist for
representative soil and/or water samples taken at the site:
• chloride concentration is 500 parts per million (ppm) or greater,
• sulfate concentration is 2,000 ppm (0.2%) or greater, or
• the pH is 5.5 or less.
Based on the Caltrans criteria, the on-site soils would not be considered corrosive to buried
metals. In addition to the above parameters, the risk of soil corrosivity to buried metals is
considered by determination of electrical resistivity (ρ). Soil resistivity may be used to express
the corrosivity of soil only in unsaturated soils. Corrosion of buried metal is an electrochemical
process in which the amount of metal loss due to corrosion is directly proportional to the flow of
DC electrical current from the metal into the soil. As the resistivity of the soil decreases, the
corrosivity generally increases. A common qualitative correlation (cited in Romanoff 1989,
NACE 2007) between soil resistivity and corrosivity to ferrous metals is tabulated below.
Table 6-3. Soil Resistivity and Corrosion Potential
Minimum Soil Resistivity (Ω-cm) Qualitative Corrosion Potential 0 to 2,000 Severe 2,000 to 10,000 Moderate 10,000 to 30,000 Mild
Over 30,000 Not Likely
Despite the relatively benign environment for corrosivity indicated by pH and water-soluble
chlorides, the resistivity testing suggests that design should consider that the soils may be
moderately corrosive to embedded ferrous metals.
Typical recommendations for mitigation of such corrosion potential in embedded ferrous metals
include:
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• a high-quality protective coating such as an 18-mil plastic tape, extruded polyethylene,
coal tar enamel, or Portland cement mortar;
• electrical isolation from above grade ferrous metals and other dissimilar metals by
means of dielectric fittings in utilities and exposed metal structures breaking grade; and
• steel and wire reinforcement within concrete having contact with the site soils should
have at least 2 inches of concrete cover.
If extremely sensitive ferrous metals are expected to be placed in contact with the site soils, it
may be desirable to consult a corrosion specialist regarding choosing the construction materials and/or protection design for the objects of concern.
6.3.3 Sulfates and Concrete
The soil sample tested in this evaluation indicated water-soluble sulfate (SO4) content of 39
parts per million (‘ppm,’ 0.004% by weight). The American Concrete Institute (ACI) 318-08
considers soil with this concentration of SO4 not to be at risk of sulfate attack to embedded
concrete (i.e., Exposure Class ‘S0’). Table 6-4 reproduces the ACI guidance.
Table 6-4. Exposure Categories and Requirements for Water-Soluble Sulfates
Exposure Category Class Water-Soluble Sulfate (SO4) In Soil (percent by weight)
Cement Type (ASTM C150) Max Water-Cement Ratio Min. f’c (psi)
Not Applicable S0 SO4 < 0.10 - - - Moderate S1 0.10 ≤ SO4 < 0.20 II 0.50 4,000
Severe S2 0.20 ≤ SO4 ≤ 2.00 V 0.45 4,500
Very severe S3 SO4 > 2.0 V + pozzolan 0.45 4,500
Adapted from: ACI 318-08, Building Code Requirements for Structural Concrete
6.3.4 Limitations
Testing to determine several chemical parameters that indicate a potential for soils to be
corrosive to construction materials are traditionally completed by the Geotechnical Engineer,
comparing testing results with a variety of indices regarding corrosion potential.
Like most geotechnical consultants, NOVA does not practice in the field of corrosion protection,
since this is not specifically a geotechnical issue. Should you require more information, a
specialty corrosion consultant should be retained to address these issues.
6.4 Earthwork
6.4.1 Standards for Earthwork
As is noted in Section 2, no structural or final civil-related design information is available at this
time. Earthwork should be performed in accordance with Section 300 of the most recent
approved edition of the “Standard Specifications for Public Works Construction” and “Regional
Supplement Amendments.”
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6.4.2 Site Preparation
Establish Erosion and Sedimentation Control
Construction-related erosion and sedimentation must be controlled in accordance
with Best Management Practices and City of Carlsbad requirements. These controls
should be established at the outset of site disturbance.
Clearing and Grubbing
Before proceeding with construction, all vegetation, root systems, topsoil, refuse, and
other deleterious non-soil materials should be stripped from construction areas.
Any existing underground utilities within the footprint of the proposed structures
should be grouted in place or removed. Clearing, including the removal of any
abandoned utilities, should be extended a minimum of 5 feet beyond the building and
pavement limits.
Stripped materials consisting of vegetation and organic materials should be hauled
away from the site, or used in landscaping non-structural areas.
6.4.3 Select Fill
All fill should be Select Fill, a mineral soil free of organics, regulated chemicals or otherwise toxic constituents, with the characteristics listed below:
• at least 40% by weight finer than ¼ inches in size;
• classified as GW, GM, GC, SW, SM, after ASTM D2487;
• maximum particle size of 4 inches; and
• expansion index (EI) of less than 20 (i.e., EI < 20, after ASTM D 4829).
Some of Unit 1 topsoil and most of Unit 2 paralic deposits will conform to the above criteria. Any
expansive clayey soils encountered during grading operations should not be used as fill.
6.4.4 Remedial Grading
The remedial grading area should include the building pad, ramp, retaining walls, and
proposed flatwork. Remedial grading should extend 2 feet outside the limits of those
improvements.
Remedial removals should extend to a depth of 12 inches below the lowest foundation element
for the building, ramp, and walls, and extend 12 inches below the subgrade of the proposed
flatwork. The exposed removal bottom should be examined by a NOVA representative to
identify any localized soft, yielding, or otherwise unsuitable materials.
The removal bottoms should be scarified to a depth of 12 inches, moisture conditioned, then
recompacted to at least 90% relative compaction.
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The soils removed during the remedial grading operations may be used for engineered fill by
moisture conditioning to 2% above the optimum moisture content and placing at 90% relative
compaction after ASTM D 1557, providing they are in conformance with the Select Fill
requirements found in Section 6.4.2.
6.5 Foundations for the Modular Building, Walls and Handicapped Ramp
6.5.1 Isolated and Continuous Foundations
Conventional foundations, consisting of isolated and continuous footings, may be employed as
described below.
Isolated and continuous foundations supported on compacted fill may be designed for an
allowable contact stress of 1,500 psf. This value may be increased by 33% for transient loads
such as wind and seismic. These foundation units should have a minimum width of 12 inches
and a thickness of 12 inches.
6.5.2 Resistance to Lateral Loads
Lateral loads to shallow foundations cast neat against the face of footing excavations may be
resisted by passive earth pressure calculated as a fluid density of 300 psf per foot of depth.
Additionally, a coefficient of friction of 0.30 between soil and the concrete base of the footing
may be used with dead loads.
6.5.3 Settlement
Foundations designed as recommended above will settle on the order of 0.5-inch or less. This
movement will occur elastically, as dead load (DL) and permanent live loads (LL) are applied. In
the usual circumstance, about 80% of this settlement will occur during the construction period.
Angular distortion due to differential settlement of adjacent, unevenly loaded footings should be
less than 1-inch in 40 feet (i.e., Δ./L less than 1:480).
6.5.4 Ground Supported Slab
Design may wish to support the modules on a conventional on-grade (ground-supported) slab.
Such a slab may be designed using a modulus of subgrade reaction (k) of 150 pounds per cubic
inch (i.e., k = 150 pci).
The actual slab thickness and reinforcement should be designed by the Structural Engineer.
NOVA recommends the slab be a minimum 5 inches thick, reinforced by at least #3 bars placed
at 16 inches on center each way within the middle third of the slabs by supporting the steel on
chairs or concrete blocks ("dobies").
Minor cracking of concrete after curing due to drying and shrinkage is normal. Cracking is
aggravated by a variety of factors, including high water/cement ratio, high concrete temperature
at the time of placement, small nominal aggregate size, and rapid moisture loss due during
curing. The use of low-slump concrete or low water/cement ratios can reduce the potential for
shrinkage cracking.
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To reduce the potential for excessive cracking, concrete slabs-on-grade should be provided with
construction or ‘weakened plane’ joints at frequent intervals. Joints should be laid out to form
approximately square panels and never exceeding a length to width ratio of 1.5 to 1.
Proper joint spacing and depth are essential to effective control of random cracking. Joints are
commonly spaced at distances equal to 24 to 30 times the slab thickness. Joint spacing that is
greater than 15 feet should include the use of load transfer devices (dowels or diamond plates).
Contraction/control joints should be established to a depth of ¼ the slab thickness, as depicted
in Figure 6-1.
Figure 6-1. Sawed Contraction Joint
6.6 Capillary Break and Underslab Vapor Retarder
6.6.1 Capillary Break
NOVA recommends that the requirements for a capillary break (‘sand layer’) be determined in
accordance with ACI Publication 302 “Guide for Concrete Floor and Slab Construction.” A
“capillary break” may consist of a 4-inch thick layer of compacted, well-graded sand should be
placed below the floor slab. This porous fill should be clean coarse sand or sound, durable
gravel with not more than 5% coarser than the 1-inch sieve or more than 10% finer than the No.
4 sieve, such as AASHTO Coarse Aggregate No. 57.
6.6.2 Vapor Retarder
Soil moisture vapor that penetrates ground-supported concrete slabs can result in damage to
moisture-sensitive floors, some floor sealers, or sensitive equipment in direct contact with the
floor. It is not the responsibility of the geotechnical consultant to provide recommendations for
vapor retarders to address this concern. This responsibility usually falls to the Architect.
Decisions regarding the appropriate vapor retarder are principally driven by the nature of the
building space above the slab, floor coverings, anticipated penetrations, concerns for mold or
soil gas, and a variety of other environmental, aesthetic, and materials factors known only to the
Architect.
A variety of specialty polyethylene (polyolefin)-based vapor retarding products are available to
retard moisture transmission into and through concrete slabs. This remainder of this section
provides an overview of design and installation guidance, and considers the use of vapor
retarders in the building construction in the San Diego area.
(Sawcut
-~ .. -. •o • 1/4 0 min-1 lJ ~---::·:1 • • p
GD .•. 10-•G re~ •. o .• o . > Induced crack , .. -·d> D . o ,e ___,,,, • • 0 • p .. o . 0 ,·o• .
.. 0 0Gi> • C Ao · .. -.,;. -
Sawed contraction joint
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Detail to support selection of vapor retarders and to address the issue of moisture transmission
into and through concrete slabs is provided in a variety of publications by the American Society
for Testing and Materials (ASTM) and the American Concrete Institute (ACI). A partial listing of
those publications is provided below.
• ASTM E1745-97 (2009). Standard Specification for Plastic Water Vapor Retarders Used
in Contact with Soil or Granular Fill under Concrete Slabs.
• ASTM E154-88 (2005). Standard Test Methods for Water Vapor Retarders Used in
Contact with Earth Under Concrete Slabs, on Walls, or as Ground Cover.
• ASTM E96-95 (2005). Standard Test Methods for Water Vapor Transmission of
Materials.
• ASTM E1643-98 (2009). Standard Practice for Installation of Water Vapor Retarders
Used in Contact with Earth or Granular Fill Under Concrete Slabs.
• ACI 302.2R-06. Guide for Concrete Slabs that Receive Moisture-Sensitive Flooring
Materials.
Vapor retarders employed for ground supported slabs in the San Diego are commonly specified
as minimum 10 mil polyolefin plastic that conforms to the requirements of ASTM E1745 as a
Class A vapor retarder (i.e., a maximum vapor permeance of 0.1 perms, minimum 45 lb/in
tensile strength and 2,200 grams puncture resistance). Among the commercial products that
meet this requirement are the series of Yellow Guard® vapor retarders vended by Poly-
America, L.P.; the Perminator® products by W. R. Meadows; and, Stego®Wrap products by
Stego Industries, LLC.
The person responsible for design of the vapor barrier should consult with product vendors to
ensure selection of the vapor retarder that best meets the project requirements. For example,
concrete slabs with particularly sensitive floor coverings may require lower permeance or other
performance-related factors are specified by the ASTM E1745 class rating.
The performance of vapor retarders is particularly sensitive to the quality of installation.
Installation should be performed in accordance with the vendor’s recommendations under full-
time surveillance.
6.7 Walls
6.7.1 Lateral Pressures
Lateral earth pressures to retaining walls are related to the type of backfill, drainage conditions,
slope of the backfill surface, and the allowable rotation of the wall. It is expected that the site
walls will be unyielding, designed to resist ‘at rest’ soil loads. Table 6-5 provides
recommendations for lateral soil for varying conditions of wall yield. Groundwater level will be
well below the wall levels.
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If footings or other surcharge loads are located a short distance outside the wall, these
influences should be added to the lateral stress considered in the design of the wall. Surcharge
loading should consider wall loads that may develop from adjacent roads and sidewalks. To
account for such potential loads, a surcharge pressure of 75 psf can be applied uniformly over
the wall to a depth of about 12 feet.
Table 6-5. Wall Lateral Loads from Soil
Condition
Equivalent Fluid Pressure (psf/foot)
Level Backfill 2:1 Backfill Sloping Upwards
Active 35 55
At Rest 55 75
Passive 350 350
6.7.2 Seismic Increment to Non-Yielding Site Walls
The lateral seismic thrust acting on a non-yielding retaining walls greater than 6 feet in height
should be estimated by the dynamic (seismic) thrust, ΔPE. Dynamic thrust is approximated as:
ΔPE = khH2γ where,
- kh , pseudostatic horizontal earthquake coefficient, equal to PGAM/2
- H is the height of the wall in feet from the footing to the point of fixity
- γ is the unit weight of the backfill, about 120 lb/ft3
The resultant dynamic thrust acts at a distance of 0.33H above the base of the wall.
6.8 Flatwork
Flatwork should be constructed on engineered fill placed in conformance with Section 6.4.4.
Exterior concrete slabs for pedestrian traffic or landscape should be at least 4 inches thick.
Weakened plane joints should be located at intervals of about 6 feet. Control of the
water/cement ratio can limit shrinkage cracking due to excess water or poor concrete finishing
or curing. Typical reinforcement for exterior slabs would consist of 6x6 W2.9/W2.9 welded wire
fabric placed securely at mid-height of the slab. As an alternative, exterior slabs and sidewalks
may be reinforced with No. 3 bars on 18 inches centers, each way.
6.9 Miscellaneous Site Structures
6.9.1 Signs and Light Poles
Sign structures and light standard foundations as columns directly embedded in the ground or
socketed in ground-embedded footings should be designed in general accordance with Section
1807 of the California Building Code (CBC). With the expectation that most of poles for signs
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and light standards will be embedded in fill, the structures will accumulate support as described
below:
• lateral resistance will accumulate at a rate of 150 pounds per square foot per foot of
depth below natural grade;
• the allowable lateral soil bearing pressure may be increased by a factor of two for short-
term lateral loads, as allowed by Section 1806A.3.4 of the CBC; and
• an allowable soil bearing pressure of 1,800 pounds per square foot may be used to
support vertical compressive loads.
6.9.2 Equipment Pads
Pads to support a variety of special equipment (for example, air conditioning equipment,
transformers, animal feed, etc.) may be supported on ground bearing slabs embedded at least 6
inches below surrounding grade.
These miscellaneous slabs should be supported on at least 12 inches of compacted, low
expansive engineered fill or undisturbed formational soils moisture conditioned to at least 2%
over optimum and then densified to at least 90% relative compaction after ASTM D 1557.
Founded as described above, ground-supported equipment and related will have an allowable
bearing capacity (qa) of qa = 1,500 psf.
6.9.3 Shade Structure
In the case of a shade structure, the structure is supported by a central column. Such columns
may be set into shallow foundations bearing on the Unit 2 Paralic Deposits. If necessary, the
periphery of the shade structure may be anchored by guy cables tied to concrete blocks.
Figure 6-2 and Figure 6-3 depict these foundations.
Figure 6-2. Footing for a Shade Structure Figure 6-3. Guy Cable Anchor
O<n'C,OC, ---, ~
-
I I ~ I I
~~/_+·-1: ;:::,:::::;,:::=====;:::;:=±4--------~~--~~~-~J-----~t
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Footings for a shade structure should be embedded at least 6 inches into the Unit 2 Paralic
Deposits. The footings should have a minimum depth of 2 feet below surrounding ground and a
minimum width of 30 inches. These footings should be designed for a bearing capacity of 2,500
psf. This value may be increased by ⅓ to adapt to transitory loads such as wind and seismic.
Passive resistance against the face of a guy cable anchor may be assumed to be 300 psf per
foot of anchor embedment.
6.10 Surfacing for the Play Area
Two broad options are available for surfacing an area for play and playground equipment.
These options provide cushioning after ASTM F1292 Standard Specification for Impact
Attenuation of Surfacing Materials Within the Use Zone of Playground Equipment.
• Option 1, Unitary. Unitary materials are generally proprietary products developed using
rubber mats and tiles, or a combination of energy-absorbing materials. The surfacing is
held in place by a binder that may be poured in place at the playground site and then
cured to form a unitary shock-absorbing surface.
• Option 2, Loose Fill. This material includes any of several loose materials (sand, wood
chips, shredded rubber, etc.) that can be placed to conform with ASTM F1292. In
general, the thickness of the loose fill is about 9 inches.
Regardless of the option chosen for development of surfacing, the Unit 2 Paralic Deposits will
serve as base material for any surfacing. Prior to any use as such, Unit 2 should be prepared as
described in Section 6.4. Thereafter, a variety of cushioning media may be placed over this
base. Figure 6-4 (following page) provides a generic description depicting the use of layered
cushioning media in an area of playground equipment.
As may be seen by review of Figure 6-4, a layered cushioning media would include a drainage
layer of gravel or similar porous media. The densified subgrade should be sloped for drainage.
In usual case, this will include minimum 2% slopes toward the collection structures that should
be discharged to an approved outlet.
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Figure 6-4. Layered Cushioning Media (source: U.S. Consumer Product Safety Commission, Public Playground Safety Handbook, December 2015)
6.11 Trenching and Backfilling for Utilities
Excavation for utility trenches must be performed in conformance with OSHA regulations
contained in 29 CFR Part 1926.
Utility trench excavations have the potential to degrade the properties of the adjacent soils.
Utility trench walls that are allowed to move laterally will reduce the bearing capacity and
increase settlement of adjacent footings and overlying slabs.
Backfill for utility trenches is as important as the original subgrade preparation or engineered fill
placed to support either a foundation or slab. Backfill for utility trenches must be placed to meet
the project specifications for the engineered fill of this project. Unless otherwise specified, the
backfill for the utility trenches should be placed in 4 to 6-inch loose lifts and compacted to a
minimum of 90% relative compaction after ASTM D 1557 (the ‘modified Proctor’) at soil moisture
+2% of the optimum moisture content. Up to 4 inches of bedding material placed directly under
the pipes or conduits placed in the utility trench can be compacted to 90% relative compaction
with respect to the Modified Proctor. Compaction testing should be performed for every 20 cubic
yards of backfill placed or each lift within 30 linear feet of trench, whichever is less.
Backfill of utility trenches should not be placed with water standing in the trench. If granular
material is used for the backfill, the material should have a gradation that will filter protect the
backfill material from the adjacent soils. If this gradation is not available, a geosynthetic non-
woven filter fabric should be used to reduce the potential for the migration of fines into the
backfill material.
Loyer 5: Im p,ad ma Is under swings
layer 4: loose-fill surfacing material
Loyer 3: Geotcxtilc do1 h
yer 2: 3-to 6-inches of loose fill (e.g., gravel for drainage
Layer 1: Hard surface (aspholt, o;:or,c:rcte, etc.)
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STORMWATER INFILTRATION
7.1 Overview
A permanent biofiltration basin is planned at the south end of the site. Based upon the
indications of the field exploration and laboratory testing reported herein, NOVA has evaluated
the site after guidance contained in the City of Carlsbad BMP Design Manual, 2016 edition
(hereinafter, ‘the BMP Manual’).
Section 3.3 provides a description of the field work undertaken to complete percolation testing.
Figure 3-1 and Plate 1 depict the location of the testing. This section provides the results of the
percolation testing and related recommendations for management of stormwater in
conformance with the BMP Manual.
The feasibility of stormwater infiltration is principally dependent on structural, geotechnical and
hydrogeologic conditions at the project site. Consideration of several geotechnical risks
preclude the implementation of infiltration BMPs for this site. NOVA concludes that the site is
not feasible for development of permanent stormwater infiltration BMPs, due to the low
infiltration rate.
This section provides NOVA’s assessment of the feasibility of stormwater infiltration BMPs
utilizing the information developed by the subsurface exploration described in Section 3, as well
as other elements of the site assessment.
7.2 Infiltration Rate
The percolation rate of a soil profile is not the same as its infiltration rate (‘I’). Therefore, the
measured/calculated field percolation rate was converted to an estimated infiltration rate utilizing
the Porchet Method in accordance with guidance contained in the BMP Manual.
Table 7-1 provides a summary of the infiltration rates determined by the percolation testing.
Table 7-1. Infiltration Rate Determined by Percolation Testing
Boring Approximate Ground Elevation (feet, msl)
Depth of Test (feet)
Approximate Test Elevation (feet, msl)
Infiltration Rate (inches/hour)
Design Infiltration Rate (in/hour, FS=3.375*)
P-1 +162 5 +157 0.03 0.009 P-2 +163 5 +158 0.06 0.018
Notes: (1) ‘FS’ indicates ‘Factor of Safety’ (2) elevations are approximate As may be seen by review of Table 7-1, a factor of safety (FS) is applied to the infiltration rate (I)
determined by the percolation testing. This factor of safety considers the nature and variability of
subsurface materials, as well as the natural tendency of infiltration structures to become less
7.0
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efficient with time. In coordination with the design engineer, Form I-9 was completed after
guidance contained in the BMP Manual, and resulted in FS = 3.375. The calculated infiltration
rates after applying FS = 3.375 is I = 0.01 inches per hour for the locations at the proposed
biofiltration basin.
Infiltration rates of 0.01 inches per hour or less imply that the soil and geologic conditions do not
allow for infiltration in an appreciable quantity without increasing geotechnical hazards.
7.3 Review of Geotechnical Feasibility Criteria
7.3.1 Overview
Section C.2 of Appendix C of the BMP Manual provides seven factors that should be considered
by the project geotechnical professional while assessing the feasibility of infiltration related to
geotechnical conditions. These factors are listed below.
• C.2.1 Soil and Geologic Conditions
• C.2.2 Settlement and Volume Change
• C.2.3 Slope Stability
• C.2.4 Utility Considerations
• C.2.5 Groundwater Mounding
• C.2.6 Retaining Walls and Foundations
• C.2.7 Other Factors
The above geotechnical feasibility criteria are reviewed in the following subsections.
7.3.2 Soil and Geologic Conditions
The sequence of subsurface materials encountered by the borings may be generalized to occur
as described below.
1. Unit 1, Topsoil. The site is covered by a layer of topsoil that is about 1-foot thick. The
topsoil is comprised of dark brown to orange brown, fine to coarse grained silty sand.
This soil may be derived from previous agricultural use or serve as landscaping for the
current playfield.
2. Unit 2, Quaternary Old Paralic Deposits (Qop). The topsoil is underlain by old paralic
deposits. As encountered in the borings, the unit is characteristically orange brown to
dark orange brown, dense to very dense in consistency, and composed of layers of silty
and clayey sandstone.
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7.3.3 Settlement and Volume Change
Settlement and volume change due to stormwater infiltration is not a concern at this site, given
that: (i) BMPs sited well-away from any structures, (ii) no potential for liquefaction, and (iii) no
potential for hydro collapse.
7.3.4 Slope Stability
BMPs should not be sited within 50 feet of an existing slope.
7.3.5 Utilities
Stormwater infiltration BMPs should not be sited within 10 feet of underground utilities.
7.3.6 Groundwater Mounding
Stormwater infiltration can result in damaging ground water mounding during wet periods.
Based on the depth to groundwater, groundwater mounding is not a risk.
7.3.7 Retaining Walls and Foundations
Stormwater infiltration BMPs should not be sited within 10 feet from retaining walls and
foundations.
7.3.8 Other
NOVA does not know of other factors that could affect implementation of stormwater infiltration
BMPs. However, the complete design is not known at this point. Risk factors could be further
identified (for example, the proximity of BMPs to utilities, retaining walls, etc.) in review of the
final design.
7.4 Recommendation for Infiltration
In consideration of the foregoing, it is the preliminary judgment of NOVA that the site is
generally not geotechnically suitable for infiltration by stormwater due to the negligible
calculated infiltration rates and associated geotechnical hazards.
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PAVEMENTS
8.1 Overview
8.1.1 General
The structural design of pavement sections depends primarily on anticipated traffic conditions,
subgrade soils, and construction materials. For the purposes of the preliminary evaluation
provided in this section,
NOVA has assumed a Traffic Index (TI) of 5.0 for the passenger car parking and 6.0 for the
driveways. These traffic indices should be confirmed prior to final design.
8.1.2 Design to Limit Infiltration
An important consideration with the design and construction of pavements is surface and
subsurface drainage. Deterioration of pavements (for example, by softening of the subgrade as
well as other factors) can be expected where standing water develops either on the pavement
surface or within the base course. The following should be considered to limit the amount of
excess moisture, which can reach the subgrade soils:
• site grading at a minimum 2% grade away from the pavements,
• compaction of any utility trenches for landscaped areas to the same criteria as the
pavement subgrade,
• sealing all landscaped areas in or adjacent to pavements to minimize or prevent
moisture migration to subgrade soils, and
• concrete curbs bordering landscape areas should have a deepened edge to provide a
cutoff for moisture flow beneath the pavement (generally, the edge of the curb can be
extended an additional 12 inches below the base of the curb).
8.1.3 Maintenance
Preventative maintenance should be planned and provided for. Preventative maintenance
activities are intended to slow the rate of pavement deterioration and to preserve the pavement
investment. Preventative maintenance consists of both localized maintenance (e.g. crack
sealing and patching) and global maintenance (e.g. surface sealing). Preventative maintenance
is usually the first priority when implementing a planned pavement maintenance program and
provides the highest return on investment for pavements.
8.1.4 Review and Surveillance
The Geotechnical Engineer-of-Record should review the planning and design for pavement to
confirm that the recommendations presented in this report have been incorporated into the
plans prepared for the project. The preparation of subgrades for roadways should be observed
on a full-time basis by a representative of the Geotechnical Engineer-of-Record.
8.0
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8.2 Subgrade Preparation
8.2.1 General
Preparation of subgrades for paved areas should include: (i) excavation and staging of the
upper 2 feet below the pavement base course, (ii) compacting the bottom of removals to at least
90% relative compaction, and (iii) replacement of the removed soil as fill compacted to at least
95% relative compaction.
8.2.2 Proof-Rolling
After the completion of compaction/densification, areas to receive pavements should be proof-
rolled. A loaded dump truck or similar should be used to aid in identifying localized soft or
unsuitable material.
Any loose, soft or unsuitable materials encountered during this proof-rolling should be removed,
replaced with an approved backfill, and compacted.
8.2.3 Timely Base Course Construction
Construction should be managed such that preparation of the subgrade immediately precedes
placement of the base course. Proper drainage of the paved areas should be provided to
reduce moisture infiltration to the subgrade.
8.3 Flexible Pavements
As is discussed in Section 3.4, laboratory testing indicated an R-value of 38 for these soils.
Provided the subgrade in paved areas is prepared per the recommendations in Section 6.4, an
R-value of 19 can be assumed for design of flexible pavements.
Table 8-1 provides recommended sections for flexible pavements. The recommended pavement
sections are for planning purposes only. Additional R-value testing should be performed on
actual soils at the design subgrade levels to confirm the pavement design.
Table 8-1. Preliminary Recommendations for Flexible Pavements
Area Estimated
Subgrade R-Value
Traffic
Index
Asphalt
Thickness (in)
Base Course
Thickness (in)
Auto Driveways/Parking 38 5 4 5
Roadways 38 6 4 6
The above sections assume the aggregate base course will be placed at a minimum of 95%
relative compaction. Construction materials (asphalt and aggregate base) should conform to the
current Standard Specifications for Public Works Construction (Green Book).
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8.4 Rigid Pavements
8.4.1 General
The flexible pavement specifications used in roadways and parking stalls may not be adequate
for truck loading and turnaround areas. In this event, NOVA recommends that a rigid concrete
pavement section be provided. The pavement section should be 7 inches of concrete over a 6-
inch base course. The concrete should be obtained from an approved mix design that conforms
with the minimum properties shown on Table 8-2.
Table 8-2. Recommended Concrete Requirements
Property Recommended Requirement
Compressive Strength @ 28 days 3,250 psi minimum
Strength Requirements ASTM C94
Minimum Cement Content 5.5 sacks/cubic yards
Cement Type Type V Portland
Entrained Air Content 6 to 8%
Concrete Aggregate ASTM C33
Aggregate Size 1-inch maximum
Maximum Water Content 0.5 lb/lb of cement
Maximum Allowable Slump 4 inches
8.4.2 Joints
Longitudinal and transverse joints should be provided as needed in concrete pavements for
expansion/contraction and isolation. Sawed joints should be cut within 24 hours of concrete
placement, and should be a minimum of 25% of slab thickness plus ¼-inch. All joints should be
sealed to prevent entry of foreign material and doweled where necessary for load transfer.
Where dowels cannot be used at joints accessible to wheel loads, pavement thickness should
be increased by 25% at the joints and tapered to regular thickness in 5 feet.
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REFERENCES
9.1 Site Specific
Grading Plans For: North County Academy, Campus Consolidation, 1640 Magnolia Avenue,
Carlsbad, California, Pasco Laret Suiter & Associates, Inc., Project No. 687995, plotted May 10,
2021.
North County Academy: Option 1, Alpha Studio Design Group, provided to NOVA October
2020.
Report, Geotechnical and Geohazard Investigation, Proposed Portable Classrooms, North
County Academy, 1640 Magnolia Avenue, Carlsbad, CA, NOVA Services, Inc., Project
2020187, December 7, 2020.
Topographic Survey Map-North County Academy School, Pasco Laret Suitor & Associates,
August 14, 2020.
9.2 Design
American Concrete Institute, 2002, Building Code Requirements for Structural Concrete (ACI
318-02) and Commentary (ACI 318R-02).
American Concrete Institute, 2015, Guide to Concrete Floor and Slab Construction, ACI
Publication 302.1R-15.
American Concrete Institute, 2016, Guide for Concrete Slabs that Receive Moisture-Sensitive
Flooring Materials (ACI 302.2R-06).
American Society of Civil Engineers, Minimum Design Load for Buildings and Other Structures,
ASCE 7-16.
California Code of Regulations, Title 24, 2019 California Building Standards Code.
California Department of Transportation (Caltrans), 2003, Corrosion Guidelines, Version 1.0,
found at http://www.dot.ca.gov/hq/esc/ttsb/corrosion/pdf/2012-11-19-Corrosion-Guidelines.pdf.
California Geological Survey, Checklist for Review of Engineering Geology and Seismology
Reports for California Public Schools, Hospitals, and Essential Service Buildings, Note 48,
October 2013.
City of Carlsbad, Engineering Standards, Volume 5, Carlsbad BMP Design Manual (Post
Construction Treatment BMPS), 2016 Edition, City of Carlsbad, February 16, 2016.
NACE International, 2007, Standard Practice, Control of External Corrosion on Underground or
Submerged Metallic Piping Systems, SPO169-2007.
9.0
44
Update Report, Geotechnical Investigation North County Academy, Campus Consolidation, Carlsbad, California NOVA Project 2020187
June 2, 2021
OSHA Technical Manual, Excavations: Hazard Recognition in Trenching and Shoring, OSHA
Instruction TED 01-00-015, Section V, Chapter 2. Found at:
https://www.osha.gov/dts/osta/otm/otm_v/ otm_v_2.html#1.
OSHPD and SEAOC, Website: Seismic Design Maps, https://seismicmaps.org/.
Romanoff, Melvin. Underground Corrosion, NBS Circular 579. Reprinted by NACE, Houston,
1989.
Standard Specifications for Public Works Construction (Green Book), Public Works Standards,
Inc.
Terzaghi, Karl, Evaluating Coefficients of Subgrade Reaction, Geotechnique, Vol 5, 1955, pp
297-326.
9.3 Geologic and Site Setting
California Geological Survey (CGS), Information Warehouse: Landslide Inventory:
https://maps.conservation.ca.gov/cgs/lsi/, accessed December 2020.
California Division of Mines and Geology (CDMG), 2008, Guidelines for Evaluating and
Mitigating Seismic Hazards in California, Special Publication 117A.
Historic Aerials website, 2020, www.historicaerials.com: accessed in October.
Kennedy, M.P. and Tan, S.S., 2007 Geologic Map of the Oceanside 30’ x 60’ Quadrangle,
California, California Geological Survey and United States Geological Survey, Scale 1:100,000.
Norris, R. M. and Webb, R. W., 1990, Geology of California, Second Edition: John Wiley & Sons, Inc.
Southern California Earthquake Data Center, 2020, Historical Earthquakes & Significant Faults in
Southern CA, https://scedc.caltech.edu/significant/index.html#, accessed in December.
Tan and Giffen, 1995, Landslide Hazards in the Northern Part of the San Diego Metropolitan
Area, San Diego County, Relative Landslide Susceptibility, Oceanside and San Luis Rey
Quadrangles, Landslide Hazard Identification Map No. 35, Open-File Report 95-04.California
Geologic Survey, 1995.
United States Geological Survey and California Geological Survey, 2011, Quaternary Fault and
Fold database for the United States, http://earthquake.usgs.gov/regional/qfaults/.
Update Report, Geotechnical Investigation North County Academy, Campus Consolidation, Carlsbad, California NOVA Project 2020187
June 2, 2021
PLATES
9"TP
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXW W XXPED RAMPNO PARKING
NO PARKING
ASPHALT
CONC
6' HIGH CHAIN LINK FENCE
6' HIGH CHAIN LINK FENCE16
3163 163163162162162162162162161
161161 161161160160
160160160160160
15
9
159
159159159159
158158158158
157
157BOVFIRE RISERSD
SDFIREELECCOMM
S S S S S S S SSDSDSDSDSDSDSDSDSDSD SSDSDSDSDSDSDSDXXXXXXXXXXXXXXXXXXXSDSDSDSDSDSDSDSDSDSDSDSDXXX X X X X X X X X X XX
SSSSSSSSSSSSD SDSDSDSDSDSDSDSDSDSDSDSDSDSDRD
RD
RD
RD
RD
SD SD SD SDSDSDSDSDSDSDSDSDSDSDSDSDSDSW & CURB
SW & CURB
8" FIRE LINE
4" WATER LINE
1.6%
INLET
6" SD 8.1%PROPOSED MODULAR BUILDING
FF=162.00
PAD=160.00
1.7%
AREA = 775 SF
159.00 FG BOT
155.00 IE
1.7%
1.6%
PROPOSED MODULAR BUILDING
FF=162.00
PAD=160.00
PROPOSED MODULAR BUILDINGFF=162.00PAD=160.00(153.40) IEQ100=0.29 CFSV100=2.9 FPS
159.50 TG
155.00 IE
163.10 FS163.50 TW159.50 TF 163.00 FS
163.45 FS
163.50 FS
163.50 TW
159.50 TF
161.85 FS
161.90 FS
161.98
FS
159.80 TG
158.30 IE
159.80 TG
157.88 IE
159.80 TG
157.60 IE
161.80 TC
161.30 FS
161.55 TC
161.05 FS
1.5%
161.50 TC
161.00 FS
161.50 TC
161.00 FS
161.70 FG 163.00 FG
159.00 IE
4'X3'
161.30 TG
159.29 IE
(158.35) FS
JOIN EX.
159.70FS-GB159.60FS1.5%161.30 TG159.90 IE(159.59) FSJOIN EX.
160.00
FG-TOP
160.90
FG-TOP
163.00
FG-TOP
161.55 FS
161.80 TW
158.47 TF
(161.00)
FG
LT
EPB
161.30 TG
159.62 IE
157.00 IE
158.4 TP
156.92 IE
(159.58) FSJOIN EX.21.5'161.50 FS/TW159.50 BW159.30 TG154.30 IE (154.20) IE 161.35 RIM153.93 IE
2"
(154.4) TP 4"
154.3 TP 2"
FH
156.00 TP
156.1
TP
158.4 TP
159.80 TG
158.02 IE
161.65 FS 1622.5%
158.40 FS
159.05
FG
159.50
FG
159.50 FG
159.65 FG 1.0%161.65 FS
161.80 TW
160.47 TF
159.70
FS-GB
8.1%159.60
FS
(158.37) FS
(158.83) TC
JOIN EX.
158.45 FS 8.1%
159.65
FS-GB
161.45 FS
161.80 TW
157.80 TF
161.45 FS
161.80 TW
157.80 TF
6'15.75'
6'24.0'7'7.90'5'DAYLIGHT
161.60 FG
160.00
FG-TOP
160.00
FG-TOP
158.40 FS 1.0%1.9%(159.45)±FS VLT (159.1)±TG INLET(153.35) IE
(163.35)
FG/FL
1.0%162.35 FL
161.60
FS-GB
159.65
FS-GB
160.10 FG
160.50
FG-TOP
2:1
2:1
161.98
FS
1.7%
EX FIELD
FNC
159.10 FG
159.13 TW
157.80 TF
(158.77) TC
(158.34) FS
5%
(159.13)
FS/TC
(159.39) FS160.60 FG/FS161.13 TW159.13 TF159.62 FL
160.10 FG160.10 FG
160.10 FG160.10 FG 162.40 FS162.83 TW159.50 TF
162.50 FS
162.83 TW
159.50 TF
159.13 TW
157.80 TF
161.35 FS-GB161.50 TW159.50 BW161.40 FS-GB161.80 TW158.47 TF
LT
DAYLIGHT
(163.1)FG
1.8%
1.4
%1.4%1.8%
1.8%1.8%1.4%1.4%8" SD PER CARLSBAD VILLAGEACADEMY PLANS PERAPPL-04-103630
RVICE
01-11
WTR PER CARLSBAD VILLAGE
ADEMY PLANS PER
PL-04-103630
154.97 IE
156.78 IE
156.76 IE 157.10 IE
158.4 TP
R
158.1 BP W
155.42 TP SD
159.04 BP SD
157.8 TP W
159.15 BP SD
153.91 TP SS
21.00'
5.50'
11.00'1.5'DAYLIGHT
3:1 160-GB
160-GB3:13:12:13:1SEE SHEET 3
161.10 IE
160.78 IE
160.38 IE
160.04 IE
157.00 IE
159.00 IE
4'X3'
156.85 BP SS
155.37 TP SD
161.65 FS
161.60 FS
161.80 TW
157.80 TF1.5%161.60 FS
161.80 TW
158.47 TF
1.
5
%
156.87 BP SS154.60 TP SD161160159.50FS159.60FS-GB160.52 FS5.0'LNDG1.3%154.30 IE
FNC
2.0%158.4 TP90°10.5'160.60 IE(161)(162)(163)(160)(160)(160)
(163)
(158)
VERY LOW WATER
HYDROZONE PER SEPARATE
LANDSCAPE PLANS
LOW WATER
HYDROZONE
PER SEPARATE
LANDSCAPE
PLANS1.0%MEDIUM WATER HYDROZONE TURFPER SEPARATE LANDSCAPE PLANSLOW WATER HYDROZONE PERSEPARATE LANDSCAPE PLANS
158.4 TP
90°BB'AA'B-2B-1B-4QopB-3P-2P-1QopPLAYGROUNDCONCRETE HARDSCAPE0020'40'NW E
N
S
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575944 Calle Amanecer, Suite FSan Clemente, CA 92673P: 949.388.7710NOVANORTH COUNTY ACADEMY - CUSD
1640 MAGNOLIA AVENUE,
CARLSBAD, CALIFORNIA GEOTECHNICALMATERIALSSPECIAL INSPECTIONSBEDVBEwww.usa-nova.comPROJECT NO.:DATE:DRAWN BY:REVIEWED BY:2020187JUNE 2021DTJMSSUBSURFACEINVESTIGATION MAPDRAWING TITLE:SCALE:1"=20'PLATE NO.1 OF 2SDVOSBSLBEKEY TO SYMBOLSQopOLD PARALIC DEPOSITSGEOTECHNICAL BORINGB-4PERCOLATION TEST BORINGP-2LIMITS OF ANTICIPATEDREMEDIAL GRADINGGEOLOGIC CROSS-SECTIONBB'----I / I -------E9 /'J L_J ,L. - -\ \ I I I I I I I I --1 I I ~ I I / / -----------------I I I I I / , , --, /~ I I 111 I I I I I ! I I I I I I I I I I I I I I I I I I I I / / ......................... -------.... -------... -... __
140180APROPOSEDMODULAR BUILDINGS1601200408020601001101301701503070105090140180A'160120130170150TD=21.5'B-2TD=21.5'B-3FF=162'QopTOPSOIL??PROPOSED MODULAR BUILDINGS140180B1601200408020601001301701503070105090160140180110150130170120140180B'160120130170150TD=21.5'B-3TD=21.5'B-4TD=5'P-2QopQop???TOPSOILPROPOSED BIO BASINFF=162'0020'40'4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575944 Calle Amanecer, Suite FSan Clemente, CA 92673P: 949.388.7710NOVANORTH COUNTY ACADEMY - CUSD
1640 MAGNOLIA AVENUE,
CARLSBAD, CALIFORNIA GEOTECHNICALMATERIALSSPECIAL INSPECTIONSBEDVBEwww.usa-nova.comPROJECT NO.:DATE:DRAWN BY:REVIEWED BY:2020187JUNE 2021DTJMSCROSS-SECTIONSAA' & BB'DRAWING TITLE:SCALE:1"=20'PLATE NO.2 OF 2SDVOSBSLBEKEY TO SYMBOLSQopOLD PARALIC DEPOSITSGEOTECHNICAL BORINGPERCOLATION TEST BORINGEXISTING GRADEB-4P-2PROPOSED GRADEGEOLOGIC CONTACT?.l .l l'J l'J /'J
Update Report, Geotechnical Investigation North County Academy, Campus Consolidation, Carlsbad, California NOVA Project 2020187
June 2, 2021
APPENDIX A
USE OF THE GEOTECHNICAL REPORT
Im ortant Information About Your
Geotechnical Engineering Report
Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes.
The following information is provided to help you manage your risks.
Geotechnical Services Are Performed for
Specific Purposes, Persons, and Projects
Geotechnical engineers structure their services to meet the specific needs of
their clients. A geotechnical engineering study conducted for a civil engi-
neer may not fulfill the needs of a construction contractor or even another
civil engineer. Because each geotechnical engineering study is unique, each
geotechnical engineering report is unique, prepared solelyfor the client. No
one except you should rely on your geotechnical engineering report without
first conferring with the geotechnical engineer who prepared it. And no one
-not even you -should apply the report for any purpose or project
except the one originally contemplated.
Read the Full Report
Serious problems have occurred because those relying on a geotechnical
engineering report did not read it all. Do not rely on an executive summary.
Do not read selected elements only.
A Geotechnical Engineering R~port Is Based on
A Unique Set of Project-Specific Factors
Geotechnical engineers consider a number of unique, project-specific fac-
tors when establishing the scope of a study. Typical factors include: the
client's goals, objectives, and risk management preferences: the general
nature of the structure involved, its size, and configuration: the location of
the structure on the site: and other planned or existing site improvements,
such as access roads, parking lots, and underground utilities. Unless the
geotechnical engineer who conducted the study specifically indicates oth-
erwise, do not rely on a geotechnical engineering report that was:
• not prepared for you,
• not prepared for your project.
• not prepared for the specific site explored, or
• completed before important project changes were made.
Typical changes that can erode the reliability of an existing geotechnical
engineering report include those that affect:
• the function of the proposed structure, as when it's changed from a
parking garage to an office building , or from a light industrial plant
to a refrigerated warehouse,
• elevation, configuration, location, orientation, or weight of the
proposed structure,
• composition of the design team, or
• project ownership.
As a general rule, always inform your geotechnical engineer of project
changes-even minor ones-and request an assessment of their impact.
Geotechnical engineers cannot accept responsibility or liability for problems
that occur because their reports do not consider developments of which
they were not informed
Subsurface Conditions Can Change
A geotechnical engineering report is based on conditions that existed at
the time the study was performed. Do not rely on a geotechnical engineer-
ing reportwhose adequacy may have been affected by: the passage of
time; by man-made events, such as construction on or adjacent to the site;
or by natural events, such as floods, earthquakes, or groundwater fluctua-
tions. Always contact the geotechnical engineer before applying the report
to determine if it is still reliable. A minor amount of additional testing or
analysis could prevent major problems.
Most Geotechnical Findings Are Professional
Opinions
Site exploration identifies subsurface conditions only at those points where
subsurface tests are conducted or samples are taken. Geotechnical engi-
neers review field and laboratory data and then apply their professional
judgment to render an opinion about subsurface conditions throughout the
site. Actual subsurface conditions may differ-sometimes significantly-
from those indicated in your report. Retaining the geotechnical engineer
who developed your report to provide construction observation is the
most effective method of managing the risks associated with unanticipated
conditions.
A Report's Recommendations Are Not Final
Do not overrely on the construction recommendations included in your
report. Those recommendations are not final, because geotechnical engi-
neers develop them principally from judgment and opinion. Geotechnical
engineers can finalize their recommendations only by observing actual
subsurface conditions revealed during construction. The geotechnical
engineer who developed your report cannot assume responsibility or
liability for the report's recommendations if that engineer does not perform
construction observation.
A Geotechnical Engineering Report Is Subject to
Misinterpretation
Other design team members' misinterpretation of geotechnical engineering
reports has resulted in costly problems. Lower that risk by having your geo-
technical engineer confer with appropriate members of the design team after
submitting the report. Also retain your geotechnical engineer to review perti-
nent elements of the design team's plans and specifications. Contractors can
also misinterpret a geotechnical engineering report. Reduce that risk by
having your geotechnical engineer participate in prebid and preconstruction
conferences, and by providing construction observation.
Do Not Redraw the Engineer's Logs
Geotechnical engineers prepare final boring and testing logs based upon
their interpretation of field logs and laboratory data. To prevent errors or
omissions, the logs included in a geotechnical engineering report should
never be redrawn for inclusion in architectural or other design drawings.
Only photographic or electronic reproduction is acceptable, but recognize
that separating logs from the report can elevate risk.
Give Contractors a Complete Report and
Guidance
Some owners and design professionals mistakenly believe they can make
contractors liable for unanticipated subsurface conditions by limiting what
they provide for bid preparation. To help prevent costly problems, give con-
tractors the complete geotechnical engineering report, but preface it with a
clearly written letter of transmittal. In that letter, advise contractors that the
report was not prepared for purposes of bid development and that the
report's accuracy is limited; encourage them to confer with the geotechnical
engineer who prepared the report (a modest fee may be required) and/or to
conduct additional study to obtain the specific types of information they
need or prefer. A prebid conference can also be valuable. Be sure contrac-
tors have sufficient time to perform additional study. Only then might you
be in a position to give contractors the best information available to you,
while requiring them to at least share some of the financial responsibilities
stemming from unanticipated conditions.
Read Responsibility Provisions Closely
Some clients, design professionals, and contractors do not recognize that
geotechnical engineering is far less exact than other engineering disci-
plines. This lack of understanding has created unrealistic expectations that
have led to disappointments, claims, and disputes. To help reduce the risk
of such outcomes, geotechnical engineers commonly include a variety of
explanatory provisions in their reports. Sometimes labeled "limitations"
many of these provisions indicate where geotechnical engineers' responsi-
bilities begin and end, to help others recognize their own responsibilities
and risks. Read these provisions closely Ask questions. Your geotechnical
engineer should respond fully and frankly.
Geoenvironmental Concerns Are Not Covered
The equipment. techniques, and personnel used to perform a geoenviron-
mental study differ significantly from those used to perform a geotechnical
study. For that reason, a geotechnical engineering report does not usually
relate any geoenvironmental findings, conclusions, or recommendations;
e.g., about the likelihood of encountering underground storage tanks or
regulated contaminants. Unanticipated environmental problems have led
to numerous project failures. If you have not yet obtained your own geoen-
vironmental information, ask your geotechnical consultant for risk man-
agement guidance. Do not rely on an environmental report prepared for
someone else.
Obtain Professional Assistance To Deal with Mold
Diverse strategies can be applied during building design, construction,
operation, and maintenance to prevent significant amounts of mold from
growing on indoor surfaces. To be effective, all such strategies should be
devised for the express purpose of mold prevention, integrated into a com-
prehensive plan, and executed with diligent oversight by a professional
mold prevention consultant. Because just a small amount of water or
moisture can lead to the development of severe mold infestations, a num-
ber of mold prevention strategies focus on keeping building surfaces dry.
While groundwater, water infiltration, and similar issues may have been
addressed as part of the geotechnical engineering study whose findings
are conveyed in this report, the geotechnical engineer in charge of this
project is not a mold prevention consultant; none of the services per-
formed in connection with the geotechnical engineer's study
were designed or conducted for the purpose of mold preven-
tion. Proper implementation of the recommendations conveyed
in this report will not of itself be sufficient to prevent mold
from growing in or on the structure involved.
Rely, on Your ASFE-Member Geotechncial
Engineer for Additional Assistance
Membership in ASFE/The Best People on Earth exposes geotechnical
engineers to a wide array of risk management techniques that can be of
genuine benefit for everyone involved with a construction project. Confer
with you ASFE-member geotechnical engineer for more information.
ASFE
The Best People an Earth
8811 Colesville Road/Suite G106, Silver Spring, MD 20910
Telephone: 301/565-2733 Facsimile: 301/589-2017
e-mail: info@asfe.org www.asfe.org
Copyright 2004 by ASFE, Inc. Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with ASFE'S
specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of ASFE, and only for
purposes of scholarly research or book review. Only members of ASFE may use this document as a complement to or as an element of a geotechnical engineering report. Any other
firm, individual, or other entity that so uses this document without being an ASFE member could be commiling negligent or intentional (fraudulent) misrepresentation.
IIGER06045.0M
Update Report, Geotechnical Investigation North County Academy, Campus Consolidation, Carlsbad, California NOVA Project 2020187
June 2, 2021
APPENDIX B
LOGS OF BORINGS
BORING LOG B-1
DEPTH (FT)SOIL CLASS.(USCS)BLOWSPER 12-INCHESEQUIPMENT:NOVEMBER 3, 2020
8-INCH DIAMETER AUGER BORING
GROUNDWATER NOT ENCOUNTERED
5
10
15
20
25
30
0
DIRECT SHEAR
EXPANSION INDEX
ATTERBERG LIMITSSIEVE ANALYSISRESISTANCE VALUE
CONSOLIDATIONSAND EQUIVALENT
CORROSIVITYMAXIMUM DENSITY
GRAPHIC LOGREMARKSBULK SAMPLESUMMARY OF SUBSURFACE CONDITIONS
(USCS; COLOR, MOISTURE, DENSITY, GRAIN SIZE, OTHER)LABORATORYCAL/SPT SAMPLEELEVATION:
DATE EXCAVATED:
EXCAVATION DESCRIPTION:
GROUNDWATER DEPTH:
MDDS
EIALSA
RVCN
SE
LAB TEST ABBREVIATIONS
CRCME 75
GPS COORD.:
SOIL DESCRIPTION
N/A
± 162.0 FT MSL
9.7%125.0 pcf
OLD PARALIC DEPOSITS (Qop): SILTY SANDSTONE; DARK ORANGE BROWN,
SLIGHTLY MOIST, MEDIUM DENSE TO DENSE, FINE TO COARSE GRAINED
SM
TOPSOIL: SILTY SAND; DARK BROWN, MOIST, LOOSE, FINE TO COARSE GRAINED,
SCATTERED GRAVEL, SOME ORGANIC MATERIAL
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
PROJECT NO.: 2020187
LOGGED BY:
REVIEWED BY:
DATE: JUN 2021
BULK SAMPLE
SPT SAMPLE ( ASTM D1586)
CAL. MOD. SAMPLE (ASTM D3550)
ERRONEOUS BLOWCOUNT
NO SAMPLE RECOVERY
GEOLOGIC CONTACT
SOIL TYPE CHANGE
#
*
KEY TO SYMBOLS
GROUNDWATER / STABILIZED
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
AR
MS
APPENDIX B.1
944 Calle Amanecer, Suite F
San Clemente, CA 92673P: 949.388.7710
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
SBEDVBE SDVOSB SLBE
SCATTERED GRAVEL
MEDIUM DENSE
ORANGE BROWN WITH GRAY MOTTLING, SLIGHTLY MOIST, DENSE, COARSE
GRAINED
CLAYEY SANDSTONE; DARK ORANGE BROWN, SLIGHTLY MOIST, MEDIUM DENSE,
COARSE GRAINEDSC
BORING TERMINATED AT 16.5 FT. NO GROUNDWATER ENCOUNTERED. NO CAVING.
SM
21
46
19
20
41 DENSE
MD
SA
CR
SA
SA
SA
SA
--
-~ ~ -
-
-
~
-~ kZ -
- - - - -----------------------------------'--------------~
-
j V
-
-
-
-
-
-
-
-
-
-
-
-
-
"'111"'/"SZ "' IZI . . .
IZI -
□ -
BORING LOG B-2
DEPTH (FT)SOIL CLASS.(USCS)BLOWSPER 12-INCHESEQUIPMENT:NOVEMBER 3, 2020
8-INCH DIAMETER AUGER BORING
GROUNDWATER NOT ENCOUNTERED
5
10
15
20
25
30
0
DIRECT SHEAR
EXPANSION INDEX
ATTERBERG LIMITSSIEVE ANALYSISRESISTANCE VALUE
CONSOLIDATIONSAND EQUIVALENT
CORROSIVITYMAXIMUM DENSITY
GRAPHIC LOGREMARKSBULK SAMPLESUMMARY OF SUBSURFACE CONDITIONS
(USCS; COLOR, MOISTURE, DENSITY, GRAIN SIZE, OTHER)LABORATORYCAL/SPT SAMPLEELEVATION:
DATE EXCAVATED:
EXCAVATION DESCRIPTION:
GROUNDWATER DEPTH:
MDDS
EIALSA
RVCN
SE
LAB TEST ABBREVIATIONS
CRCME 75
GPS COORD.:
SOIL DESCRIPTION
N/A
± 160.0 FT MSL
FILL (Afu): SILTY SAND; DARK ORANGE BROWN, MOIST, MEDIUM DENSE, FINE TO
MEDIUM GRAINED
SM
TOPSOIL: SILTY SAND; DARK BROWN, MOIST, LOOSE, FINE TO COARSE GRAINED,
SCATTERED GRAVEL, SOME ORGANIC MATERIAL
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
PROJECT NO.: 2020187
LOGGED BY:
REVIEWED BY:
DATE: JUN 2021
BULK SAMPLE
SPT SAMPLE ( ASTM D1586)
CAL. MOD. SAMPLE (ASTM D3550)
ERRONEOUS BLOWCOUNT
NO SAMPLE RECOVERY
GEOLOGIC CONTACT
SOIL TYPE CHANGE
#
*
KEY TO SYMBOLS
GROUNDWATER / STABILIZED
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
AR
MS
APPENDIX B.2
944 Calle Amanecer, Suite F
San Clemente, CA 92673P: 949.388.7710
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
SBEDVBE SDVOSB SLBE
FINE GRAINED
OLD PARALIC DEPOSITS (Qop): CLAYEY SANDSTONE; DARK ORANGE BROWN,
MOIST, MEDIUM DENSE, FINE TO MEDIUM GRAINED
POORLY GRADED SANDSTONE WITH CLAY; DARK ORANGE BROWN WITH GRAY
MOTTLING, MOIST, MEDIUM DENSE, MEDIUM GRAINED
SC
SP-SC
BORING TERMINATED AT 21.5 FT. NO GROUNDWATER ENCOUNTERED. NO CAVING.
SM
32
27
55
26
48
SILTY SANDSTONE; DARK ORANGE BROWN, MOIST, DENSE, FINE TO COARSE
GRAINED
39 WET, FINE TO MEDIUM GRAINED
SM
MD
EI
RV 10.4%123.6pcf
11.8%127.9pcf
1 VERY LOW
-' 1
-J
-IJ -----. t_
IX ---
----- - - - -----------------------------------'---------- - - - -~;~ ~ -~r: _;:;: - - - - -- - -----------------------------------... ----------- - -
-
-
-~ -
-
-
-
-V -
-
-
-
-
-
-
-
-
"'111"'/"SZ "' IZI . . .
IZI --
□ -
BORING LOG B-3
DEPTH (FT)SOIL CLASS.(USCS)BLOWSPER 12-INCHESEQUIPMENT:NOVEMBER 3, 2020
8-INCH DIAMETER AUGER BORING
GROUNDWATER NOT ENCOUNTERED
5
10
15
20
25
30
0
DIRECT SHEAR
EXPANSION INDEX
ATTERBERG LIMITSSIEVE ANALYSISRESISTANCE VALUE
CONSOLIDATIONSAND EQUIVALENT
CORROSIVITYMAXIMUM DENSITY
GRAPHIC LOGREMARKSBULK SAMPLESUMMARY OF SUBSURFACE CONDITIONS
(USCS; COLOR, MOISTURE, DENSITY, GRAIN SIZE, OTHER)LABORATORYCAL/SPT SAMPLEELEVATION:
DATE EXCAVATED:
EXCAVATION DESCRIPTION:
GROUNDWATER DEPTH:
MDDS
EIALSA
RVCN
SE
LAB TEST ABBREVIATIONS
CRCME 75
GPS COORD.:
SOIL DESCRIPTION
N/A
± 163.0 FT MSL
OLD PARALIC DEPOSITS (Qop): SILTY SANDSTONE WITH CLAY; DARK ORANGE
BROWN TO BROWN,MOIST, MEDIUM DENSE
SM
TOPSOIL: SILTY SAND; DARK BROWN, MOIST, LOOSE, FINE TO COARSE GRAINED,
SCATTERED GRAVEL, SOME ORGANIC MATERIAL
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
PROJECT NO.: 2020187
LOGGED BY:
REVIEWED BY:
DATE: JUN 2021
BULK SAMPLE
SPT SAMPLE ( ASTM D1586)
CAL. MOD. SAMPLE (ASTM D3550)
ERRONEOUS BLOWCOUNT
NO SAMPLE RECOVERY
GEOLOGIC CONTACT
SOIL TYPE CHANGE
#
*
KEY TO SYMBOLS
GROUNDWATER / STABILIZED
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
AR
MS
APPENDIX B.3
944 Calle Amanecer, Suite F
San Clemente, CA 92673
P: 949.388.7710
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
SBEDVBE SDVOSB SLBE
SILTY SANDSTONE/SANDY SILTSTONE; DARK ORANGE BROWN TO BROWN, MOIST,
VERY DENSE
SILTY SANDSTONE WITH CLAY; ORANGE BROWN WITH GRAY MOTTLING, SLIGHTLY
MOIST, MEDIUM DENSE, FINE TO MEDIUM GRAINED
BORING TERMINATED AT 21.5 FT. NO GROUNDWATER ENCOUNTERED. NO CAVING.
SM
21
55
23
18
42
DARK ORANGE BROWN, MOIST, DENSE, MEDIUM GRAINED
51 DARK ORANGE BROWN WITH GRAY MOTTLING, VERY MOIST TO WET
DARK ORANGE BROWN TO GRAY BROWN, MOIST, DENSE
ORANGE BROWN WITH GRAY MOTTLING, MEDIUM DENSE
SM
SA
SA
SA
SA
SA
SA
11.3%126.1pcfSM/ML
DRILLING BECOMES MORE
DIFFICULT
FINE GRAINED
-
-~ -~
-~ ...... - - -'-- -----------------------
-
------------I--------------
1,..-
-- - - -'-- -
----------------------------------I--------------~ -
-
-
kZ -
-
-
-
-
-~ z
-
--
-
-V -
-
-
-
-
-
-
-
-
"'111"'/"SZ "' IZI . . .
IZI --
□ -
BORING LOG B-4
DEPTH (FT)SOIL CLASS.(USCS)BLOWSPER 12-INCHESEQUIPMENT:NOVEMBER 3, 2020
8-INCH DIAMETER AUGER BORING
GROUNDWATER NOT ENCOUNTERED
5
10
15
20
25
30
0
DIRECT SHEAR
EXPANSION INDEX
ATTERBERG LIMITSSIEVE ANALYSISRESISTANCE VALUE
CONSOLIDATIONSAND EQUIVALENT
CORROSIVITYMAXIMUM DENSITY
GRAPHIC LOGREMARKSBULK SAMPLESUMMARY OF SUBSURFACE CONDITIONS
(USCS; COLOR, MOISTURE, DENSITY, GRAIN SIZE, OTHER)LABORATORYCAL/SPT SAMPLEELEVATION:
DATE EXCAVATED:
EXCAVATION DESCRIPTION:
GROUNDWATER DEPTH:
MDDS
EIALSA
RVCN
SE
LAB TEST ABBREVIATIONS
CRCME 75
GPS COORD.:
SOIL DESCRIPTION
N/A
± 163.0 FT MSL
OLD PARALIC DEPOSITS (Qop): CLAYEY SANDSTONE; DARK ORANGE BROWN,
SLIGHTLY MOIST, MEDIUM DENSE, FINE GRAINED
SC
TOPSOIL: SILTY SAND; DARK BROWN, MOIST, LOOSE, FINE TO COARSE GRAINED,
SCATTERED GRAVEL, SOME ORGANIC MATERIAL
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
PROJECT NO.: 2020187
LOGGED BY:
REVIEWED BY:
DATE: JUN 2021
BULK SAMPLE
SPT SAMPLE ( ASTM D1586)
CAL. MOD. SAMPLE (ASTM D3550)
ERRONEOUS BLOWCOUNT
NO SAMPLE RECOVERY
GEOLOGIC CONTACT
SOIL TYPE CHANGE
#
*
KEY TO SYMBOLS
GROUNDWATER / STABILIZED
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
AR
MS
APPENDIX B.4
944 Calle Amanecer, Suite F
San Clemente, CA 92673P: 949.388.7710
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
SBEDVBE SDVOSB SLBE
ORANGE BROWN
SM
BORING TERMINATED AT 21.5 FT. NO GROUNDWATER ENCOUNTERED. NO CAVING.
SM
28
23
24
24
31
SILTY SANDSTONE WITH CLAY; ORANGE BROWN, MOIST, MEDIUM DENSE, MEDIUM
GRAINED
32 WET
ORANGE BROWN WITH GRAY-BROWN MOTTLING, VERY MOIST TO WE, DENSE
9.6%119.5pcf
888 I
-I ---
----
~ ----- - - - -'-- -
----------------------------------I--------------
kZ -
-
-
kZ -
-
-
-
-~ -
-
-
-
-V -
-
-
-
-
-
-
-
-
"'111"'/"SZ "' IZI . . .
IZI -
□ -
PERCOLATION BORING LOG P-1
DEPTH (FT)SOIL CLASS.(USCS)BLOWSPER 12-INCHESEQUIPMENT:NOVEMBER 3, 2020
8-INCH DIAMETER AUGER BORING
GROUNDWATER NOT ENCOUNTERED
5
10
15
20
25
30
0
DIRECT SHEAR
EXPANSION INDEX
ATTERBERG LIMITSSIEVE ANALYSISRESISTANCE VALUE
CONSOLIDATIONSAND EQUIVALENT
CORROSIVITYMAXIMUM DENSITY
GRAPHIC LOGREMARKSBULK SAMPLESUMMARY OF SUBSURFACE CONDITIONS
(USCS; COLOR, MOISTURE, DENSITY, GRAIN SIZE, OTHER)LABORATORYCAL/SPT SAMPLEELEVATION:
DATE EXCAVATED:
EXCAVATION DESCRIPTION:
GROUNDWATER DEPTH:
MDDS
EIALSA
RVCN
SE
LAB TEST ABBREVIATIONS
CRCME 75
GPS COORD.:
SOIL DESCRIPTION
N/A
± 163.0 FT MSL
OLD PARALIC DEPOSITS (Qop): CLAYEY SANDSTONE; ORANGE BROWN, SLIGHTLY
MOIST, MEDIUM DENSE, FINE GRAINED
SC
TOPSOIL: SILTY SAND; DARK ORANGE BROWN, MOIST, LOOSE, FINE TO COARSE
GRAINED, SCATTERED GRAVEL
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
PROJECT NO.: 2020187
LOGGED BY:
REVIEWED BY:
DATE: JUN 2021
BULK SAMPLE
SPT SAMPLE ( ASTM D1586)
CAL. MOD. SAMPLE (ASTM D3550)
ERRONEOUS BLOWCOUNT
NO SAMPLE RECOVERY
GEOLOGIC CONTACT
SOIL TYPE CHANGE
#
*
KEY TO SYMBOLS
GROUNDWATER / STABILIZED
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
AR
MS
APPENDIX B.5
944 Calle Amanecer, Suite F
San Clemente, CA 92673
P: 949.388.7710
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
SBEDVBE SDVOSB SLBE
BORING TERMINATED AT 5 FT AND CONVERTED TO A PERCOLATION WELL.
SM888 =--
-
~
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
"'111"'/"SZ "' IZI . . .
IZI -
□ -
PERCOLATION BORING LOG P-2
DEPTH (FT)SOIL CLASS.(USCS)BLOWSPER 12-INCHESEQUIPMENT:NOVEMBER 3, 2020
8-INCH DIAMETER AUGER BORING
GROUNDWATER NOT ENCOUNTERED
5
10
15
20
25
30
0
DIRECT SHEAR
EXPANSION INDEX
ATTERBERG LIMITSSIEVE ANALYSISRESISTANCE VALUE
CONSOLIDATIONSAND EQUIVALENT
CORROSIVITYMAXIMUM DENSITY
GRAPHIC LOGREMARKSBULK SAMPLESUMMARY OF SUBSURFACE CONDITIONS
(USCS; COLOR, MOISTURE, DENSITY, GRAIN SIZE, OTHER)LABORATORYCAL/SPT SAMPLEELEVATION:
DATE EXCAVATED:
EXCAVATION DESCRIPTION:
GROUNDWATER DEPTH:
MDDS
EIALSA
RVCN
SE
LAB TEST ABBREVIATIONS
CRCME 75
GPS COORD.:
SOIL DESCRIPTION
N/A
± 163.0 FT MSL
OLD PARALIC DEPOSIT (Qop): CLAYEY SANDSTONE; DARK ORANGE BROWN,
SLIGHTLY MOIST, MEDIUM DENSE, FINE TO COARSE GRAINED
SC
TOPSOIL: SILTY SAND; DARK ORANGE BROWN, MOIST, LOOSE, FINE TO COARSE
GRAINED
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
PROJECT NO.: 2020187
LOGGED BY:
REVIEWED BY:
DATE: JUN 2021
BULK SAMPLE
SPT SAMPLE ( ASTM D1586)
CAL. MOD. SAMPLE (ASTM D3550)
ERRONEOUS BLOWCOUNT
NO SAMPLE RECOVERY
GEOLOGIC CONTACT
SOIL TYPE CHANGE
#
*
KEY TO SYMBOLS
GROUNDWATER / STABILIZED
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
AR
MS
APPENDIX B.6
944 Calle Amanecer, Suite F
San Clemente, CA 92673
P: 949.388.7710
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
SBEDVBE SDVOSB SLBE
BORING TERMINATED AT 5 FT AND CONVERTED TO A PERCOLATION WELL.
SM888 =--
-
~
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
"'111"'/"SZ "' IZI . . .
IZI -
□ -
Update Report, Geotechnical Investigation North County Academy, Campus Consolidation, Carlsbad, California NOVA Project 2020187
June 2, 2021
APPENDIX C
LABORATORY ANALYTICAL RESULTS
Laboratory tests were performed in accordance with the generally accepted American Society for Testing and Materials (ASTM) test methods or suggested
procedures. Brief descriptions of the tests performed are presented below:
LAB TEST SUMMARY
BY: CLS
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
·CLASSIFICATION: Field classifications were verified in the laboratory by visual examination. The final soil classifications are in accordance with the
Unified Soils Classification System and are presented on the exploration logs in Appendix B.
·MAXIMUM DENSITY AND OPTIMUM MOISTURE CONTENT (ASTM D1557 METHOD A,B,C): The maximum dry density and optimum moisture
content of typical soils were determined in the laboratory in accordance with ASTM Standard Test D1557, Method A, Method B, Method C.
·DENSITY OF SOIL IN PLACE (ASTM D2937): In-place moisture contents and dry densities were determined for representative soil samples. This
information was an aid to classification and permitted recognition of variations in material consistency with depth. The dry unit weight is determined in
pounds per cubic foot, and the in-place moisture content is determined as a percentage of the soil's dry weight. The results are summarized in the
exploration logs presented in Appendix B.
·EXPANSION INDEX (ASTM D4829): The expansion index of selected materials was evaluated in general accordance with ASTM D4829. Specimens
were molded under a specified compactive energy at approximately 50 percent saturation (plus or minus 1 percent). The prepared 1-inch thick by 4-inch
diameter specimens were loaded with a surcharge of 144 pounds per square foot and were inundated with tap water. Readings of volumetric swell were
made for a period of 24 hours.
·CORROSIVITY (CAL. TEST METHOD 417, 422, 643): Soil PH, and minimum resistivity tests were performed on a representative soil sample in general
accordance with test method CT 643. The sulfate and chloride content of the selected sample were evaluated in general accordance with CT 417 and CT
422, respectively.
· R-VALUE (ASTM D 2844): The resistance Value, or R-Value, for near-surface site soils were evaluated in general accordance with California Test (CT)
301 and ASTM D 2844. Samples were prepared and evaluated for exudation pressure and expansion pressure. The equilibrium R-value is reported as
the lesser or more conservative of the two calculated results.
·GRADATION ANALYSIS (ASTM C 136 and/or ASTM D422): Tests were performed on selected representative soil samples in general accordance with
ASTM D422. The grain size distributions of selected samples were determined in accordance with ASTM C 136 and/or ASTM D422. The results of the
tests are summarized on Appendix C.3 through Appendix C.13.
APPENDIX: C.14373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
944 Calle Amanecer, Suite FSan Clemente, CA 92673P: 949.388.7710
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
www.usa-nova.com
SBEDVBE SDVOSB SLBE
DATE: JUNE 2021 PROJECT: 2020187
A ~--. . •
LAB TEST RESULTS
Sample
Location Soil Description
Dry Density
(pcf)
B-1 Orange Brown Silty Sandstone
Sample
Depth
(ft.)
5 125.0
Density of Soil in Place (ASTM D2937)
Moisture
(%)
9.7
B-2 Dark Orange Brown Clayey Sandstone2.5 123.610.4
B-2 Dark Orange Brown Clayey Sandstone7.5 127.911.8
B-3 Dark Orange Brown Silty Sandstone5 126.111.3
B-4 Dark Orange Brown Clayey Sandstone2.5 119.59.6
APPENDIX: C.2
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
944 Calle Amanecer, Suite FSan Clemente, CA 92673
P: 949.388.7710
SBEDVBE SDVOSB SLBE
Sample
Location Soil Description
Maximum
Dry Density
(pcf)
Optimum Moisture
Content
(%)
B- 1 Dark Orange Brown Silty Sandstone
Sample
Depth
(ft.)
2 - 5 135.1 8.1
Maximum Dry Density and Optimum Moisture Content (ASTM D1557)
Sample
Location
Expansion
Index
B-2 1
Expansion Index (ASTM D4829)
1 - 5
Sample Depth
(ft.)
Expansion
Potential
Very Low
DATE: JUNE 2021BY: CLS
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
Corrosivity (Cal. Test Method 417,422,643)
Sample
Location
Sample Depth
pH
Resistivity Sulfate Content Chloride Content
B-1 2 - 5 8.6 3300 39
(ppm)
32 0.003
(%)(Ohm-cm)(ft.)
0.004
(ppm)(%)
Sample
Location Soil Description R-Value
B-2 Dark Orange Brown Clayey Sandstone
Sample
Depth
(ft.)
1 - 5 38
Resistance Value (Cal. Test Method 301 & ASTM D2844)
B- 2 Dark Orange Brown Clayey Sandstone1 - 5 132.5 7.9
PROJECT: 2020187
,, ~--. . .
Gravel
GRADATION ANALYSIS TEST RESULTS
Sand
Coarse FineMediumCoarseFine
Silt or Clay
Sample Location:
Depth (ft):
USCS Soil Type:
Passing No. 200 (%):
B-1
2 - 5'
SM
35
BY: CLS APPENDIX: C.3
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
944 Calle Amanecer, Suite FSan Clemente, CA 92673P: 949.388.7710
SBEDVBE SDVOSB SLBE
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
DATE: JUNE 2021 PROJECT: 2020187
C)
C: 'in
1/) n, a. -C: Cl) (.) ... Cl) a.
~ Size (Inches) ~~::'.:-----U.S. Standard Sieve Sizes Hydrometer Analysis
0 0 ~~ -st co ;e g ~ 0 ~ ~~ ~~ 0 0 0 0 0 0 0
100.0 TT,-,--,,--,----,--t; ........ _,;a--,e.._,..-;;;i:_=ii!-rr_----r-.... ,~'--r------,7=--,rr,C-.:Z::;-,--y,,_---:Z::;-_,_---:Z:;:,---,,...:;z:;._,~~~~-~-----~-----~ ,_._ -+. I : :
I '~ I I
90 .0 -t-t--t-t-+-t-t-t-----t'----+++++-+'-f--+-'--+----'--++-'+1 -+"411't-+-'+--+-+---'1'------+-li--+.!..i1 --l-+--1-+----l-----l-l-l-l-l--+-_j_-l-_C--_ _j
\ : :
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80.0 -t-t--t-t-+-t-t-t-----#---+++++--11----f--+-l-+----1--++-ll-l --l--j~--l+--~---+-+---llf---+-11-1-t-11 --l--1--1--1----l-----l-l-l-l-l--1-_j_-l-_'--_ _j
I I I
: \ : :
70. 0 -t-t-+-+--t-+-+---t--ii1 ,,---t--H--H-h1,-t---t--.,,+---.,-t-+.:+-+-+-+-.,+-"\+--l-~:--+1-+.-1 +-+-+-l--+---+----l-l--l----l---1---1---l----1--____j
I 1 1 I I
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60 .0 -t-t-+-t-+-+-+--+---t'---+++++--+'-+-+-_!_-l-_ _!_++':+-++-+--'-l-+-\~l--'-:---l--11--1-'-: +-+--l--+----l----1-----l-l_)_j---l---l---1----l----1--____j I \ I I : \ : :
I ~ I I
50. 0 tttt+-t-t-+----tt----++++-+--+t-+-+-++---++H,tt+-+-+f-+---+-\c,-+, -+++i,-l--l---l---l---l----t---++-.J.-l---t-l--l--l----1---___j
: " : 40.0 -t-t--t-t-+-+-t--+---t.-----++++-+-+.--+-+----.--+------.-++.1,+-+-+-l---af---l---+-.-----'"-+++.1-l--l---l---l---l---l-----l-+--l--l--1-l--l--l----1---_J '-I : ..
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30 .0 -t-t-++-+-+-+--+--+1'---++-++-+---+'1-+--+__J'-+-__J'-+µ'1-1-+-J---1.'l-+--I-_L'_-++_µ.'+-+-+---l----l----l-----l-l_)_j_j__j_-L---l---L-____j
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100 10 0.1 0.01 0.001
Grain Size (mm)
Gravel
GRADATION ANALYSIS TEST RESULTS
Sand
Coarse FineMediumCoarseFine
Silt or Clay
Sample Location:
Depth (ft):
USCS Soil Type:
Passing No. 200 (%):
B-1
5'
SM
47
BY: CLS APPENDIX: C.4
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
944 Calle Amanecer, Suite FSan Clemente, CA 92673P: 949.388.7710
SBEDVBE SDVOSB SLBE
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
DATE: JUNE 2021 PROJECT: 2020187
C)
C: ·;;;
(/)
('ti a. c (1)
0 "-(1) a.
~ Size (Inches) ~~~----U.S. Standard Sieve Sizes .,,. ..... Hydrometer Analysis .,,.
0 0 ~ :::!: ~ ~ "Q" co ~ g ~ 0 ~
:. """"-M-"""" -M ~ _g _g ~ ~ _g Q 100 TTTT-,--11J-■,-"7-1-J-1,...IJ-------,&a.--=_::r--,...,l"i-----:-:r:_:1 __ i£:r----..!...,.-TT11rrr",-,----r,,---------,.---------,_____...,,------,T'"it,-,-----r---,---,----,-,-----,,,,---,---,-------,-,-----,---,
f ,.._~I I l ,
I \ I
90 ++++-+-+---l-+-----t~--++++-+---+'--+--+~-+--~-+-+-'1+-+~1•"r-t-~11-+-----t-~-++--+-'+-+-+--+--+--+---++-t--1-+-t-1-+----+------, : ' : : \1
80 ++-+-+-+--+-+---+------+1----+-++-+--+-----H--+--+-f--+--------<---+-+++-+-+---+---il.i<-------+-<-------+-t-+-+++-+->-----+---+---+----+-+-+-+-+-+--+-+---+---------i
I ~ : \
70 -+-+-+-+---+-+-l-+----+----++--+-+-+---+r---+---+--+---++-.1-t--1--+-+-----.-l-\..,__--+----++-h+-+---+----+---+---+---++-+-+--+-t-1-+---+------, II I I I : I I~ I I
I \
60 -+-+-+-+-+-+-l-+----+----++-+-+-+---+"--+---+--+---1-+r:+-+--+-+----1-+--\,,_ __ +-+-+-'+-+-t-11-+----+----++-+-+-+--+--+---+---+-------,
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50 -+-+-+-+---+-+-l-+----+t-----++--+-+-+---++---+---+--+-+----+-+-+-l-t--1--+-+-+l-+---+-O----'----d-+-+f+-+---+--+---+---+---++-+-+--+-t-1-+---+------,
I', • I I
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I
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I
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I
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10 -+-+-+-+-+-+-t--+----+----++-+-+-+---+,---+---+---+---++.:+-+--+-+---cl-+----+----+-+---r.+-+--+--+---+---+---+-+-+-+--+-t-1-+----+------,
I
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100 10 0.1 0.01 0.001
Grain Size (mm)
Gravel
GRADATION ANALYSIS TEST RESULTS
Sand
Coarse FineMediumCoarseFine
Silt or Clay
Sample Location:
Depth (ft):
USCS Soil Type:
Passing No. 200 (%):
B-1
7-10'
SM
44
BY: CLS APPENDIX: C.5
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
944 Calle Amanecer, Suite FSan Clemente, CA 92673P: 949.388.7710
SBEDVBE SDVOSB SLBE
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
DATE: JUNE 2021 PROJECT: 2020187
C)
C: 'in
1/) n, a. -C: Cl) (.) ... Cl) a.
~ Size (Inches) ~+::'.:----U.S. Standard Sieve Sizes Hydrometer Analysis
0 0
-st co ;e g ~ 0 ~
~ ci ci ci ci ci ci
100.0 TT,,,,,---,-,-------,.-,---e--,--,--,--■.,-,.....-ii~ia.--=--::::i:-ez~~n-r1.::;2:.......,-Y,,----:Z~---,-___:;~:__---.-,_:;:2;:;,_~~---.--~--m--------
l t, I I
11 : :
90 .0 -tt-t-t-+-t--+---t---t'---l-+-t-+-1---t'--+--+--'-+----'--++'+-+-+\+-1'+-+---+----'--+++'-l-1 -1--1------l-1------l----l--l-l---l--1--1----l----l...-_j_ _ _J ~ I I
\I I
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80.0 ++-t-+--+--+-+--+----+~--+++++-41-+-+--+-.jl------1--++ll-l---l---+---tj,...~---+--l--~---l-J._j.jll-l--+-l--1---1------1---U-l.__j___j_--L_j__j____j_ _ __J
\ I
\ : 70 .0 ++-t-t-+-i---t-t--tT11---++++-+-rr1 ,-+--+--.-+1-~1-H...+-+1 -+--+-.1+--•~.---+-~1--H-M-+-+-+-+---+---1-1---1-1-1---1---1---1-_J1---_ _j
\ :
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60 .0 -tt-t-t-+-l-i-t----t'----tt++-+-t'---j-+--'--+----'--H-4-+-+-+--'-l--+--''\l---'----1-l-1.!..JI --1----1-+--l---+---1-l---l-l-l---1-+---l-_j __ _J I
I \
I
I \ 50. 0 tt-t-+-t-+-+--+---tt------++t-+t--tf-+-+-+-1c---+-+l-it+-++-+---t+--+-l--~,-++--l-l,i-l---+----t--l--l-----l---l-l-l---+---l---l----l---l----+--__J
~ • 40 .0 -tt-t-t-+-li--t-t--+.--++++-+-h--l-+--.--+-----.--++..+--+-+-+--.1--+---+~--+++.-J: --1--+-+-+---+-----l-l---l----l--1-+--l-_j __ _j
I
I
I
30 .0 -tt-t-t-+-li-+-t---t'-'--++++-+-+1-1--+--+--1~---'--1-H.LJ-l-1 -+--l----'-11---+----l--1'_-++-1-.1..j_'j_j...-1-___j_--1---j_)__jl---l--l--l--L-----L-_J__ _ __J
20. 0 -tt-t-t-+-t--+---+---tt---1-+-t-+-1--tt-+--t--+-t---t-++t+-+-+-+-t+-+---+---1--++-+++-l--l------l-l----+----l--l-1---l--l--l----l----l...-_j_-_J
I
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10.0 ++-+++-1-i-t---+.---++++-t-+.-if--+--;-f..--;..-H++-+-+-;l--+---+___:~-H-1-.;..J: --l---l-+--l---+-----l-l---l-l-1---1-+---l-_jl---_ _J
I
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I 0 .0 +-'-_L_L_j__L_l_L____J_J_l , __ -+-1-_j_J__L_lJ_I I_J____L_L...J_, _ __j_,--+1.lL.l'_J_-1......J'L__J____j__j'~--+J_l-1..L 'L..l__j___j_ _ _j__ __ .µ_LL-1--1--L___l _ _L _ __J
100 10 0.1 0.01 0.001
Grain Size (mm)
Gravel
GRADATION ANALYSIS TEST RESULTS
Sand
Coarse FineMediumCoarseFine
Silt or Clay
Sample Location:
Depth (ft):
USCS Soil Type:
Passing No. 200 (%):
B-1
7.5'
SM
29
BY: CLS APPENDIX: C.6
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
944 Calle Amanecer, Suite FSan Clemente, CA 92673P: 949.388.7710
SBEDVBE SDVOSB SLBE
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
DATE: JUNE 2021 PROJECT: 2020187
C)
C: ·;;;
(/)
('ti a. c (1)
0 "-(1) a.
~ Size (Inches) ~~~----U.S. Standard Sieve Sizes .,,. ..... Hydrometer Analysis .,,.
0 0 ~ :::!: ~ ~ "Q" co ~ g ~ 0 ~
:. """"-M-"""" -M g_ ~ _g ~ ~ _g Q 100 ,-,---,--,---,--1-•,_t--r-11_9-1,...------T""T'--r-•-h--,-----l~.....,------,a~~-r,:cr,'",-.---,-,r-',.---------._____...,..-------,-,..,.,,-.--.---,----.--,----,----,---,,,-----,---,-------,-~---.-------,
'11
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90 ++++-+-+---l-+----t~--++++-+---+'--+--+~-+--~-+-+-':h,+-+-+----'-t--l---+-~-+++-+-+-t-11-+----+---+++-+--+-+--+---+---+-------,
: \
I 0 80 +-+-+-+--+--+-+--+---++----++-+-+-+--++--+---+--+-+----+-+-+-11+-+-➔'r'\+-+1-+---+-t----++-+t+-+--+---+---+--+----++-+-+--+--t-1-+---+-------<
' : \ 70 +-+-+-+--+--+-+--+---+1-,---++-+-+-+---+r,--+---+-,-+---,.------+~.+-+--+-~ih+-1 ----l----+--,---++-+--,+-+--+---+---+---+---++-+-+--+--t-1-+---+-------<
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60 +-+-+-+--+--+-+--+---+----++-+-+-+---+"--+---+--+---1-, +-+":+-+--+-+----~\---+---+----+-+-+-'+-+--t-11-+---+----++-+-+-+--+--+---+--+--------,
I I \
: : \ 50 +-+-+-+--+--+-+--+---+f-----++-+-+-+--++--+---+--+-+----+-+-+i+-+--+-+-+>-------'1•~~-+----+--++-+H--+--t-11-+---+----+++-+-+--+--+---+--+--------,
: : \
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40 ++++-+-+---1-+----+~--++++-+---t-.-+--+~-+----,~1 ++.:++-+--+-------.-1-+----+-'~-++-h-t--+-t-11-+----+---+++-+--+-+--+---+---+-------,
: '• I '-.
II I I I I I I 'i,. I 30 ++t-t--t-----t-----t---+----t-"--------t---t-t----t----t-----t'--+-----t-~1--'-j-~,t-t--t-t--"t------t-----t-~------1--t-..t::1::t--t-+----t--+--t-----+-t-t--+----t-+---+-------t----------i
I I
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I I 20 +-+-+-+---+-+-+--+---+f-----++-+-+-+--++--+---+--f--+----+-+-+i+-+--+-+-+l-+---+-t----++-+-f+-+--+---+---+---+---++-+-+--+--t-1-+---+-------<
I I
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10 +-+-+-+--+--+-+--+---+----++-+-+-+---+,---+---+--+---++.:+-+--+-+---cl-+---+----++---r.:+-+--+--+---+--+----+-+-+-+--+--t-1-+---+-------<
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I I 0 +-'-~~-~~~l~•---+-~~•-----+-'-+---0----+-'~'--+-~•~~~-•~-1-~•~----~--+--'--~~--~-------a
100 10 0.1 0.01 0.001
Grain Size (mm)
Gravel
GRADATION ANALYSIS TEST RESULTS
Sand
Coarse FineMediumCoarseFine
Silt or Clay
Sample Location:
Depth (ft):
USCS Soil Type:
Passing No. 200 (%):
B- 1
10'
SC
26
BY: CLS APPENDIX: C.7
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
944 Calle Amanecer, Suite FSan Clemente, CA 92673
P: 949.388.7710
SBEDVBE SDVOSB SLBE
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
DATE: JUNE 2021 PROJECT: 2020187
~ Size (Inches) ~~ U.S. Standard Sieve Sizes '-./ Hydrometer Analysis '-.,,. ..... .,,.
0 0
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Grain Size (mm)
I I I I I I I
Gravel
GRADATION ANALYSIS TEST RESULTS
Sand
Coarse FineMediumCoarseFine
Silt or Clay
Sample Location:
Depth (ft):
USCS Soil Type:
Passing No. 200 (%):
B- 3
2.5'
SM
40
BY: CLS APPENDIX: C.8
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
944 Calle Amanecer, Suite FSan Clemente, CA 92673
P: 949.388.7710
SBEDVBE SDVOSB SLBE
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
DATE: JUNE 2021 PROJECT: 2020187
C)
C: ·u;
II) ns a. -C: Q) (.)
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~ Size (Inches) ~~:::::-----U.S. Standard Sieve Sizes Hydrometer Analysis
0 0
'SI' CX) ;e g 55 0 ~
ci ci ci ci ci ci ci
100.0 TT,-,--,,--,----,-Tl,--~h-... -..--;;;...,ii!rr,...----r_-., ... z=--._--__ ,~=-....... TT:~Z::;-T""'T:,---:Z::;-_~z~,---,,..:;2:;.-;~~~~-~-----~------
1, I
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90 .0 tt--H-++-+--+--f'----++++-+--f'--+--+---'---+----'---++':+-+-"1'l~H---':+-+--+---'----tt-1-'-:-I---J---1---1---J----l-----l-1--l-+-+--l---l---l----l---
l ' I I I I\ I
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I 80 .0 tt--H-++-+--+--#---++++-+--#-+--+--+-+---+--l----l-l+-+-+--l--''1--J+-----l----l-----l----l-l--l-l-+-+--l---l---l----l-----l-l--l-+-+_J_--l---l----l---
1 ', I
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70 .0 tt--H-++-+--+-ii1 ,,-------++++-i-----+,11-+----t---.1,+----,1-+h:+-++-t-----.1t\1 \c---t--+~1--+l-h-1 +-+--1---1---l----l-----l-l-+-+-+-+---1---l----1--__J
I \ I : \ :
60 .0 tt+-t-+-+-+--+--+'---++++-+-+'-+--+--'--l---'-++'-1+-++-+----'-!--4111'"'t--+-----'----l-ll----l--'-1 +-+--l--+---l---+-----l-l~+-+--l---1-+-+---1--__J : \
I \
50 .0 tttt+-H-f----t+---t++++-tt--4-+-r-+--+-++tl-l +-J-+--t+---+-'+---+--l+-l+ll ---l---l-.J---l----l----l-1--l--i-..J---+--l---+-____j--___j
I \
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40 .0 tt+-t-+-+-+--+--+r-----+++++-+r---+-+---..---l----..---++.-:+-++-+---.!--+--l---~---l-l ..... _,_,!+-+-+--+---l---+-----l-l~--1---1---l-+-+--l--__J
I I
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30. 0 ++++-+-+-+--+--+''---++-++-+---+'1-+-+__J'-+-__J'-+µ'1-++-l---L'l---+--I---_J_'_--l-l-1-L'+-+--l---l---l----l-----l-l~--l---l---l---l---l--__J
I I
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I I 20 .0 -t-t-t-t--t--t---t----t--tt-----t-t-H-+--tt-f--t----l-+---+-Ht+-+-t-+-t+--+----l-----lf----+++t++-1--+--+-+----+-l-l-+--l----l--+--I-----I---
I I
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10. 0 tt+-t-+-+-+--+--+.---++++-+-+.-+--+-~-1--~++.:+-++-~+-+--!--_._-++-I-'-: +-+--l---1---l----1-----1--1--1-+-+--1---l---1----1--__J
I I
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I I 0 .0 -t-'-...L.l.__j__...L_...L___J__ _ _ul 'L----J-_LL...l.......l_JJI I_J____1___l'LL---1'-+U'L.LJ__L...J'L__J___L__...J.'_-+LIJ_'L..l___[___[__j_ _ __[_ __ _µ_LL.L__L__j__l._ _ _j_ _ __J
100 10 0.1 0.01 0.001
Grain Size (mm)
Gravel
GRADATION ANALYSIS TEST RESULTS
Sand
Coarse FineMediumCoarseFine
Silt or Clay
Sample Location:
Depth (ft):
USCS Soil Type:
Passing No. 200 (%):
B- 3
5'
SM/ML
55
BY: CLS APPENDIX: C.9
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
944 Calle Amanecer, Suite FSan Clemente, CA 92673P: 949.388.7710
SBEDVBE SDVOSB SLBE
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
DATE: JUNE 2021 PROJECT: 2020187
C)
C: ·;;;
(/)
('ti a. c (1)
0 "-(1) a.
~ Size (Inches) ~~~----U.S. Standard Sieve Sizes .,,. ..... Hydrometer Analysis .,,.
0 0 ~ :::!: ~ ~ "Q" co ~ g ~ 0 ~
:. """"-M-"""" -M g _g _g ~ ~ _g Q 100 ,--,-,-,--,----9t-illl,_ ........... __ ,..._---1 __ ...,_...,..., __ _,_..._._. ... ___ ~a,i~..,-._TTl.-r"..------r-,,n--'"r-----,----l---.--r.,.,,..-----r----,-----,-------,--,-----------,-r,-----,----,----,------,--------,------,
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90 +++-+-+--+--+--+----t-'------t-++-+--t-----t'--+--+-~t---'-----t-t-'-l-t-f-~,~.+--+----+~--++--1-'-1--+-t-+----tf---+---++-H-+--t---+---+-+--------, ,:
' 80 ++-+-+-+-+---+---+---tf-------<-++-+-+-----H---+---+---+-t---t-----+-Ht-+-+---+----if<--+---+----+--++-+H--+-t-+-----<f----+---++-1-1-+-+--+----+---+-------<
70 ++-+-+-+-+---+---+-411---++44-+-~,--+---+--,--+---.------+-.~.+-+--1-----+-.a--~,,--+--,--++~,.+---+--+--+---+--l-----+-+-+---.....+--+-+--+---+------I
\
' 60 ++-+-+-+-+---+---+----,.-------1-++-+-+-----+"---+---+-~t----1 ++-'-t-+-+-+----'-t---+-+'-----..1----++--+-'+-+-t-+-----1f----+---++-I-I-+-+--+---+---+-------< : ,..,
I
I 50 ++-+-+-+-+---+---+---tf-------<-++-+-+-----H---+---+---+-t---t-----+-Ht-+-+---+----iH--+---+----+--++-+H--+-t-+-----<f----+---++-1-1-+-+--+----+---+-------<
I
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40 +++-+-+--+--+--+--+.------t-++-+--t-+.--+--+-~t---~: ++.-t-+-+--+-----.t---+--+--~----+-+--h.+-t-+--+--+--f-----+-t-+-f-+--+--+--+----+------1
30 ++-+-+-+-+---+---+-411~--++44-+-~·--+---+-~1-1---'-+-'~'+-+-+-+~'4--+---+~'--++~·'+-+--+--+---+--l-----+-+-+---.....+--+-+--+---+------I
20 ++-+-+-+-+---+---+---tf--------i-++-+-t-1+--+---+---+-t---t-----+-Ht-+-+---+----iH--+---+----+--++-+H--+-t-+-----<f----+---++-I-I-+-+--+--+---+-------<
10 ++-+-+-+-+---+---+--+.-------1-++-+-+----+c---+---+-~t---,------+-+c+-t-+---+---c+--+---+~--++--+-c+--+-t-+-----1f----+---++-I-I-+-+--+---+---+-------<
0 +--'-~~~~-~l•~----+--'-~~~•~~~•-1----------+-'~'~~~•~-+-~~•---+-~'~~~~-~---+-~~~~~~------1
100 10 0.1 0.01 0.001
Grain Size (mm)
Gravel
GRADATION ANALYSIS TEST RESULTS
Sand
Coarse FineMediumCoarseFine
Silt or Clay
Sample Location:
Depth (ft):
USCS Soil Type:
Passing No. 200 (%):
B- 3
7.5'
SM
31
BY: CLS APPENDIX: C.10
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
944 Calle Amanecer, Suite FSan Clemente, CA 92673P: 949.388.7710
SBEDVBE SDVOSB SLBE
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
DATE: JUNE 2021 PROJECT: 2020187
en C: "iii Ill co a.
'E
Q)
(.) '-Q) a.
~ Size (Inches) ~~~----U.S. Standard Sieve Sizes / ..... Hydrometer Analysis
0 0 ~ ~ ~ ~ """ 00 ~ g ~ 0 ~
:.. ~-C'J-~ -M g_ _g_ ~ ~ ~ _g Q 100 ,--,-,-,--rl-•~.-,..~--~---------,-,--,--•-h--,-~~------il ...... a-r~,crr",-.-,-1.-',.-------.___,,.,r---,-.,...,.,,-.--r---,----.----.--,-----,--,,,---,--,------,-~---.----.
~ :
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90 ++-++-+-t-f---t---t~--++++--+--+'--+--+~-+--~++'1+-+\-\lc--+---'-lf--+----+-~-++-+'+--+-+--+--+--+---+++-+-+-t-1-+----+-----, I I. I
I \ I
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80 +-+-+-+--+--+-t--+---+f-----+++-+-+---++--+---+--f--+----+-++1+-+--+-+-+t--+---+-l----++-H+-+--+---+---+--+----++-+-+--+--+----<-+---+-----<
I \ I : ,:
70 +-+-+-+--+--+-t--+---+1-,--+++-+-+---+r,--+---+-,-+---,--+-~:+--1--+-~➔1,1--+---+-,---+~,+-+--+---+---+--+---++-+-+--+--+----<-+---+-----<
I : \
60 --t---t--c-t-r-t-----J-----J-------j-~---;----t-t-t--j-------f-'----t-----t----"--------!-~----t-t--'1T--t--,---,-___,_,_\_____,__,__~----t--t----t"-t----i------t------t-------t---t--------t-t---t-t---;-------j--------t---------t---t--------j : \
I I
I I. 50 +-+-+-+--+--+-t--+---+f-----+++-+-+---++--+---+--f--+----+-++1+-+--+-+-+t---l-'---+-l----++-H+-+--+---+---+--+---++-+-+--+--+----<-+---+-----<
I \ : \
40 ++-++-+-t-f---t---t~--++++--+---t.-+--+~-+--~++.:+-+-+--+---..-f--+-----t--.'~-++-+.+--+--t-1f--+----+---++++--+-+--+--+--+--------,
I '\~
I '-
30 +-+-+-+--+--+-t--+---+l~•---+++-+-+--+"-1 --+---+~'-+---'----+~:+-+--+-+-------""11--+---+-'~--+'+-¥"■"r--+--+---+---+--+---++-+-+--+--+----<-+---+-----<
I
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I 20 +-+-+-+--+-+-t--+---tf-----+++-+-+---++--+---+--f--+----+-++1+-+--+-+-+t--+---+-l----++-H+-+--+---+---+--+---++-+-+--+--+----<-+---+-----<
I
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10 +-+-+-+--+--+-t--+---+----+++-+-+---+c--+---+~-+---++-:+-+--t-t---cl--+---+----++--+-c+-+--+---+---+--+---++-+-+--+--t----1-+---+-----<
I
I
I 0 +-'-~-+-~~~~l~•---+~~~•~~~•-+---'---+-~'~-+-~•~+-~-'~--+~'~~~~--+---+-'-~-+-~-~~-----a
100 10 0.1 0.01 0.001
Grain Size (mm)
Gravel
GRADATION ANALYSIS TEST RESULTS
Sand
Coarse FineMediumCoarseFine
Silt or Clay
Sample Location:
Depth (ft):
USCS Soil Type:
Passing No. 200 (%):
B- 3
10'
SM
25
BY: CLS APPENDIX: C.11
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
944 Calle Amanecer, Suite FSan Clemente, CA 92673P: 949.388.7710
SBEDVBE SDVOSB SLBE
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
DATE: JUNE 2021 PROJECT: 2020187
C)
C: ·;;;
(/)
('ti a. c (1)
0 "-(1) a.
~ Size (Inches) ~~~----U.S. Standard Sieve Sizes .,,. ..... Hydrometer Analysis .,,.
0 0 ~ :::!: ~ ~ "Q" co ~ g ~ 0 ~
:. """"-M-"""" -M g_ ~ _g ~ ~ _g Q 100 ,--,-,--,-----,--1-•,_t--r-11_9-1,...------T""T'--r-•-h--,----1~ ...... -------,i~a--,-r,:cr,'",-.---,-:r-',.---------._____...,..-------,-,..,.,,-.--.---,----.--,----,----,---,,,-----,---,-------,-~---.-------,
~\ :
90 ++++-+-+---l-+----t~--++++-+---+'--+--+~-+--~-+-+-'1-t--1-'\-f-+------'-ll-+----+-~-++--+-'+-+-+--+--+--+---++-t--1--+--t-1-+----+------,
: It :
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80 +-+-+-+--+-+-+--+---++----++-+-+-+--++--+---+--+-+----+-+-+-11+-+--+-\1-----+l1-+---+-t----++-+t+-+--+---+---+--+---++-+-+--+--+-----<-+---+-------<
: \ :
I \1
70 +-+-+-+--+-+-+--+---+1-,--++-+-+-+---+r,--+---+-,-+---,.------+~:-t--1--+-~~~:I-+---+-,---++-+--,+-+--+---+---+--+----++-+-+--+--+-----<-+---+-------<
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60 +-+-+-+--+-+-+--+---+----++-+-+-+---+"--+---+--+---1-+r1+-+--+-+----H\---+-_-+-__ +-+-+-'+-+--+-----<1-+---+----++-+-+-+--+--+---+--+--------, : : \
I I \
I I 50 +-+-+-+--+-+-+--+---+f-----++-+-+-+--++--+---+--+-+----+-+-+i+-+--+-+-+l-1~,--+---+--++-+H--+--+-----<I-+---+----++-+-+-+--+--+---+--+--------,
I I \ : : \
40 ++++-+-+---l-+----+~--++++-+---t-.-+--+~-+----1 ++.1++-+--+-------.-1-+------'-t\-~-+++.+-+-+--+--+--+---++-t--1--+--t-1-+----+------, I I \
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30 +-+-+-+--+-+-+--+---+1_1 _--++-+-+-+--+'-l--+---+---+-l -+---"-+-l ~:+-+--+-+--"-ll-+---+-•~•,,__++-~I+-+--+---+---+--+---++-+-+--+--+-----<-+---+-------<
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I 20 +-+-+-+--+--+-+--+---+f-----++-+-+-+--++--+---+--f--+----+-+-+i+-+--+-+-+l-+---+-t----++-+-f+-+--+---+---+--+----++--t--1--+-+-----<-+---+-------<
I I
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10 +-+-+-+--+-+-+--+---+----++-+-+-+---+,---+---+--+---++.:+-+--+-+---cl-+---+----++---r.:+-+--+--+---+--+---+-+-+-+--+--+-----<-+---+-------<
I I
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I I 0 +-'-~~-~~~1_,_--+_~~·---·-+---"-t-'~'--+-~·~+-~-·~--+~'~----~--+--'--~~--~-------a
100 10 0.1 0.01 0.001
Grain Size (mm)
Gravel
GRADATION ANALYSIS TEST RESULTS
Sand
Coarse FineMediumCoarseFine
Silt or Clay
Sample Location:
Depth (ft):
USCS Soil Type:
Passing No. 200 (%):
B - 3
15'
SM
22
BY: CLS APPENDIX: C.12
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
944 Calle Amanecer, Suite FSan Clemente, CA 92673P: 949.388.7710
SBEDVBE SDVOSB SLBE
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
DATE: JUNE 2021 PROJECT: 2020187
C)
C: ·;;;
(/)
('ti a. c (1)
0 "-(1) a.
~ Size (Inches) ~~~----U.S. Standard Sieve Sizes .,,. ..... Hydrometer Analysis .,,.
0 0 ~ :::!: ~ ~ "Q" co ~ g ~ 0 ~
:. """"-M-"""" -M g_ ~ _g ~ ~ _g Q 100 ,--,-,--,-----,--1-•,_t--r-11_9-1,...------T""T'--r-•-h--,----1~ ...... -------,i~a--,-r,:cr,'",-.---,-:r-',.---------._____...,..-------,-,..,.,,-.--.---,----.--,----,----,---,,,-----,---,-------,-~---.-------,
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: \ :
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100 10 0.1 0.01 0.001
Grain Size (mm)
Gravel
GRADATION ANALYSIS TEST RESULTS
Sand
Coarse FineMediumCoarseFine
Silt or Clay
Sample Location:
Depth (ft):
USCS Soil Type:
Passing No. 200 (%):
B - 3
20'
SM
15
BY: CLS APPENDIX: C.13
NOVA
GEOTECHNICAL
MATERIALS
SPECIAL INSPECTION
4373 Viewridge Avenue, Suite BSan Diego, CA 92123P: 858.292.7575
www.usa-nova.com
944 Calle Amanecer, Suite FSan Clemente, CA 92673P: 949.388.7710
SBEDVBE SDVOSB SLBE
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
DATE: JUNE 2021 PROJECT: 2020187
C)
C: ·;;;
(/)
('ti a. c (1)
0 "-(1) a.
~ Size (Inches) ~~~----U.S. Standard Sieve Sizes .,,. ..... Hydrometer Analysis .,,.
0 0 ~ :::!: ~ ~ "Q" co ~ g ~ 0 ~
:. """"-M-"""" -M g_ ~ _g ~ ~ _g Q 100 ,--,-,--,-----,--1-•,_t--r-11_9-1,...------T""T'--r-•-h--,----1~ ...... -------,i~a--,-r,:cr,'",-.---,-:r-',.---------._____...,..-------,-,..,.,,-.--.---,----.--,----,----,---,,,-----,---,-------,-~---.-------,
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: It :
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: \ :
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I I
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I I
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100 10 0.1 0.01 0.001
Grain Size (mm)
Update Report, Geotechnical Investigation North County Academy, Campus Consolidation, Carlsbad, California NOVA Project 2020187
June 2, 2021
APPENDIX D
INFILTRATION FEASIBILITY
DOCUMENTS
Appendix I: Forms and Checklists
I-3 February 2016
Categorization of Infiltration Feasibility
Condition
Form I-8
Part 1 - Full Infiltration Feasibility Screening Criteria
Would infiltration of the full design volume be feasible from a physical perspective without any undesirable
consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
1
Is the estimated reliable infiltration rate below proposed
facility locations greater than 0.5 inches per hour? The response
to this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.2 and Appendix
D.
2
Can infiltration greater than 0.5 inches per hour be allowed
without increasing risk of geotechnical hazards (slope stability,
groundwater mounding, utilities, or other factors) that cannot
be mitigated to an acceptable level? The response to this
Screening Question shall be based on a comprehensive evaluation of
the factors presented in Appendix C.2.
Provide basis:
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
Provide basis:
The infiltration rate of the existing soils for locations P-1 and P-2, based on the on-site
infiltration study was calculated to be less than 0.5 inches per hour (0.01 inches per
hour) after applying a factor of safety (FS) of FS= 3.375.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
No. See Criterion 1.
X
X
Appendix I: Forms and Checklists
I-4 February 2016
Form I-8 Page 2 of 4
Criteri
a Screening Question Yes No
3
Can infiltration greater than 0.5 inches per hour be allowed
without increasing risk of groundwater contamination (shallow
water table, storm water pollutants or other factors) that cannot
be mitigated to an acceptable level? The response to this
Screening Question shall be based on a comprehensive evaluation of
the factors presented in Appendix C.3.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
4
Can infiltration greater than 0.5 inches per hour be allowed
without causing potential water balance issues such as change
of seasonality of ephemeral streams or increased discharge of
contaminated groundwater to surface waters? The response to
this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.3.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
Part 1
Result
*
If all answers to rows 1 - 4 are “Yes” a full infiltration design is potentially feasible.
The feasibility screening category is Full Infiltration
If any answer from row 1-4 is “No”, infiltration may be possible to some extent but
would not generally be feasible or desirable to achieve a “full infiltration” design.
Proceed to Part 2
*To be completed using gathered site information and best professional judgment considering the definition of MEP in
the MS4 Permit. Additional testing and/or studies may be required by the City to substantiate findings.
Provide basis:
Provide basis:
Proceed to Part 2
No. See Criterion 1.
No. See Criterion 1.
X
X
Appendix I: Forms and Checklists
I-5 February 2016
Form I-8 Page 3 of 4
Part 2 – Partial Infiltration vs. No Infiltration Feasibility Screening Criteria
Would infiltration of water in any appreciable amount be physically feasible without any negative
consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
5
Do soil and geologic conditions allow for infiltration in any
appreciable rate or volume? The response to this Screening
Question shall be based on a comprehensive evaluation of the
factors presented in Appendix C.2 and Appendix D.
6
Can Infiltration in any appreciable quantity be allowed
without increasing risk of geotechnical hazards (slope
stability, groundwater mounding, utilities, or other factors)
that cannot be mitigated to an acceptable level? The response
to this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.2.
Provide basis: The infiltration rate of the existing soils for locations P-1 and P-2, based on the on-site
infiltration study was calculated to be 0.01 inches per hour, after applying a factor of safety
(FS) of FS=3.375.
Infiltration rates equal to or less than 0.01 inches per hour indicate that the soil and geologic conditions do not allow for infiltration in any appreciable rate or volume.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
C2.1 A geologic investigation was performed at the subject site.C2.2 Settlement and volume change due to stormwater infiltration is not a concern with: (i) low expansive soils,(ii) no potential for liquefaction, and (iii) no potential for hydro collapse. C2.3 Infiltration has the potential to cause slope failures. BMPs are to be sited a minimum of 50 feet away from any slope.C2.4 Infiltration can potentially damage subsurface and underground utilities. As planned, BMPs are not located within 10 feet of underground utilities.C2.5 Stormwater infiltration can result in damaging ground water mounding during wet periods. Mounding is not considerd to be a hazard of infiltration at this site due to the depth of groundwater. C2.6 BMPs are not anticipated to be located near foundations or retaining walls. Infiltration has the potential to increase lateral pressure and reduce soil strength which can impact foundations and retaining walls.C2.7 Other Factors: NOVA is not aware of all subsurface conditions on nearby sites and cannot address the potential effects of added saturation to geotechnical hazards like saturation, heave, settlement or hydrocollapse, liquefaction, etc. Accordingly, NOVA recommends potential for lateral migration of water from stormwater BMP’s be limited by siting any such structures away from property lines.
X
X
Appendix I: Forms and Checklists
I-6 February 2016
Form I-8 Page 4 of 4
Criteria Screening Question Yes No
7
Can Infiltration in any appreciable quantity be allowed
without posing significant risk for groundwater related
concerns (shallow water table, storm water pollutants or other
factors)? The response to this Screening Question shall be based
on a comprehensive evaluation of the factors presented in
Appendix C.3.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
8
Can infiltration be allowed without violating downstream
water rights? The response to this Screening Question shall be
based on a comprehensive evaluation of the factors presented in
Appendix C.3.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates.
Part 2
Result*
If all answers from row 5-8 are yes then partial infiltration design is potentially feasible.
The feasibility screening category is Partial Infiltration.
If any answer from row 5-8 is no, then infiltration of any volume is considered to be
infeasible within the drainage area. The feasibility screening category is No Infiltration.
*To be completed using gathered site information and best professional judgment considering the definition of MEP in
the MS4 Permit. Additional testing and/or studies may be required by the City to substantiate findings.
Provide basis:
Provide basis:
No
Infiltration
Based on the relatively low measured infiltration rates, it is NOVA's judgment that infiltration
should not be considered at this site.
Based on the relatively low measured infiltration rates, it is NOVA's judgment that infiltration
should not be considered at this site.
X
X
Appendix I: Forms and Checklists
I-7 February 2016
Factor of Safety and Design Infiltration Rate
Worksheet Form I-9
Factor Category Factor Description Assigned
Weight (w)
Factor
Value (v)
Product (p)
p = w x v
A Suitability
Assessment
Soil assessment methods 0.25
Predominant soil texture 0.25
Site soil variability 0.25
Depth to groundwater / impervious
layer 0.25
Suitability Assessment Safety Factor, SA = p
B Design
Level of pretreatment/ expected
sediment loads 0.5
Redundancy/resiliency 0.25
Compaction during construction 0.25
Design Safety Factor, SB = p
Combined Safety Factor, Stotal= SA x SB
Observed Infiltration Rate, inch/hr, Kobserved
(corrected for test-specific bias)
Design Infiltration Rate, in/hr, Kdesign = Kobserved / Stotal
Supporting Data
1
2
2
1
0.25
0.50
0.50
0.25
1.5
3
2
1
1.5
0.50
0.25
2.25
3.375
P-1=0.03
P-2=0.06
Briefly describe infiltration test and provide reference to test forms:
Design Phase Borehole percolation tests were utilized for all percolation borings (P-1
and P-2) at the bottom of the prospective infiltration BMP structure accompanied by an exploratory engineering boring (B-4) to depths of at least 10 feet below the bottom
elevation of the BMP structure. In coordination with the design engineer, a factor of
safety of FS = 3.375 was determined following the guidance in the BMP Manual.
P-1=0.01
P-2=0.01
Update Report, Geotechnical Investigation North County Academy, Campus Consolidation, Carlsbad, California NOVA Project 2020187
June 2, 2021
APPENDIX E
GUIDE SPECIFICATIONS FOR
EARTHWORK
Guide Specifications for Earthwork
1
GENERAL
Intent
It is intended that these Guide Specifications for Earthwork be used in conjunction with the
attached geotechnical report. These Guide Specifications are a part of the recommendations
contained in the attached geotechnical report. In case of conflict between the two documents,
the specific recommendations in the attached geotechnical report shall supersede these Guide
Specifications.
At the present time the Geotechnical Engineer-of-Record (GEOR) for this work is NOVA
Services, Inc. The GEOR shall provide geotechnical observation and testing during earthwork
and grading. Based on these observations and tests, the GEOR may provide new or revised
recommendations that could supersede these specifications or the recommendations in the
geotechnical report(s).
The Geotechnical Report attached to these Guide Specifications has been for the convenience
of the Contractor. The data on soil conditions is not intended as a representation or warranty of
the continuity of such conditions between borings or indicated sampling locations. It shall be
expressly understood that only the Contractor is responsible for any interpretations or
conclusions drawn therefrom. The Contractor is responsible for performing any other soil
investigations it feels is necessary for proper evaluation of the site for the purposes of planning
and/or bidding the project, at no additional cost to the Owner.
Project Organization
Owner
As used herein, Owner is intended to reference the owner of the property or the entity on whose behalf the earthwork is being performed. In the usual case, the Owner will have engaged a Contractor for execution of the earthwork.
Contractor
Responsibilities
The Contractor is the entity solely responsible for completion of the project. In some
instances, the Contractor may be a Construction Manager.
The Contractor shall review and accept the plans, geotechnical report(s), and these Guide Specifications prior to commencement of grading. The Contractor shall be solely
responsible for performing grading and backfilling in accordance with the current, approved plans and specifications. The supervision of the Contractors’ construction personnel or specialty subcontractors is solely the responsibility of the Contractor.
Coordination
The Contractor shall inform the owner and the GEOR of changes in work schedules at least one working day in advance of such changes so that appropriate observations and
Guide Specifications for Earthwork
2
tests can be planned and accomplished. The Contractor shall not assume that the GEOR is aware of all grading operations.
Surveying
The Contractor is solely and completely responsible for the accuracy of the line and grade of all features related to earthwork. The Contractor shall engage a professional
surveyor registered in the State of California to perform the necessary layout, survey control, and monumentation
Earthwork Subcontractor
General
The Contractor will retain a number of specialty subcontractors to complete separate elements of the project. In the usual case, an Earthwork Subcontractor will be among these specialty subcontractors. Moreover, other separate specialty contractors may have their own requirements for conduct of portions of the earthwork (for example, utility installation, stormwater BMPs, foundation construction, etc.). As used herein, Earthwork Subcontractor refers to any specialty subcontractor with responsibility for the execution of earthwork for this project.
Qualifications
The Earthwork Subcontractor shall be qualified, experienced, and knowledgeable in earthwork logistics, preparation and processing of ground to receive fill, moisture-
conditioning and processing of fill, and compacting fill.
Unsatisfactory Work
If, in the opinion of the GEOR, unsatisfactory conditions, such as unsuitable soil,
improper moisture condition, inadequate compaction, adverse weather, etc., are resulting in a quality of work less than required in these specifications, the GEOR shall reject the work and may recommend to the Owner that earthwork and grading be
stopped until unsatisfactory condition(s) are rectified.
Geotechnical Engineer-of-Record (GEOR)
Project Role
The GEOR is the soil engineering and engineering geology consulting firm retained to provide geotechnical services for the project. At a minimum, the GEOR shall support the project by provision of a Soil Engineer and an Engineering Geologist. Both shall be appropriately licensed by the State of California
Responsibilities
Prior to commencement of earthwork and grading, the GEOR shall meet with the Contractor and/or the Earthwork Subcontractor to review planning for earthwork, allowing the GEOR to schedule sufficient personnel to perform the appropriate level of
observation, mapping, and compaction testing.
During earthwork and grading, the GEOR shall observe, map, and document subsurface exposures to verify geotechnical design assumptions. If observed conditions are found to be significantly different than the interpreted assumptions during the design phase,
Guide Specifications for Earthwork
3
the GEOR shall inform the Owner, recommend appropriate changes in design to accommodate these observed conditions, and notify the review agency where required.
At a minimum, subsurface areas to be geotechnically observed, mapped, elevations recorded, and/or tested shall be those listed below.
• Natural ground after clearing to receiving fill but before fill is placed.
• Bottoms of all "remedial removal" areas.
• Bearing surfaces of all shallow foundations.
• All key bottoms.
• Benches made on sloping ground to receive fill. The GEOR shall observe moisture-conditioning and processing of the subgrade and fill materials, and perform relative compaction testing of fill to determine the attained relative compaction. The GEOR shall provide Daily Field Reports to the Owner and the
Contractor on a routine and frequent basis.
EXCAVATION
General
Excavations for foundations, as well as over-excavation for remedial purposes, shall be
evaluated by the GEOR.
Classification
Unless otherwise specified, excavations will be classified as described below.
1. Unclassified excavation is the excavation of all materials that can be excavated,
transported, and unloaded using heavy ripping equipment and heavy rubber tired loaders or scrapers with pusher tractors. This classification includes rocks smaller than 1 cubic yard.
2. Rock excavation is the excavation of all hard, compacted, or cemented materials that require blasting or the use of unusually large ripping and excavating equipment. This classification includes the removal of isolated rocks larger than 1 cubic yard.
Variations in Excavations
Remedial and foundation removal depths shown on geotechnical plans are estimates only. The
actual extent of removal shall be determined by the GEOR based on the field evaluation of
exposed conditions during grading.
It is likely that variations in the subsurface may be encountered that will require excavation in
excess of the foundation lines and grades depicted on the drawings. Excavations may be varied
in depth, width, and length; or slopes increased or decreased, for the purpose of obtaining the
most stable or economical final result.
Guide Specifications for Earthwork
4
Disposition of Excavated Material
Topsoil
Immediately after clearing and grubbing, and before general excavation commences, topsoil
(the layer of soils high in organics and including the root zone, herbaceous vegetation, and
grasses) shall be removed as directed by the GEOR.
Topsoil to be reused for landscaping fill or other nonstructural applications shall be stockpiled at
convenient, approved locations. Stockpiled material shall be lightly compacted by several
passes of hauling and spreading equipment.
Suitable Excavated Material
In so far as it is practical, all materials resulting from site excavations that conform with the materials criteria for Select Fill identified in the attached geotechnical report shall be used for
permanent construction.
Unsuitable Excavated Material
Excavated materials which are unsuitable for use as Select Fill shall be disposed of as
designated by the Owner. In the event these materials are disposed of on-site, the unsuitable
soils shall be placed in non-structural areas. Soils disposed of on-site shall be spread and
graded in uniform layers, densified, and shaped to ensure drainage.
Any asphalt pavement material removed during clearing operations should be properly disposed
of in approved off-site facility. Concrete fragments that are free of reinforcing steel may be
placed in fills if approved by the GEOR.
Excavated expansive soils (i.e., EI > 50, after ASTM D 4829) may be disposed of on-site in non-
structural areas, as directed by the GEOR. In the usual case, this will require burial at depths
greater than 3 feet below finished site grades.
Over Excavation in ‘Cut”
In the event development of a building pad creates a circumstance of transition between
compacted fill and naturally occurring rock, the rock will be undercut as depicted in Figure 1
(following page).
Guide Specifications for Earthwork
5
Figure 1. Undercut in a Transition Zone
Foundation Preparation and Backfilling
Foundation Preparation
Excavations for foundations shall be made to the dimensions given in the drawings, at the
working elevations given in the drawings.
The width shall generally be of the width of the concrete and depth as shown on the drawings,
according to availability of the desired bearing capacity of soil below. Bearing surfaces in direct
contact with foundations that are disturbed by excavation shall be redensified/recompacted.
Any excavation that are taken below the specified depths and levels shall be restored by the
Contractor at his own cost.
Any adjacent structures which may be damaged by on-site excavations should be underpinned.
Backfilling
Backfilling around foundations and behind walls shall not be undertaken without consideration of the curing and strength requirements for the concrete. This information may be obtained from
the Structural Engineer.
Backfilling around foundations shall be placed symmetrically and in uniform layers in order to prevent harmful eccentric loading on a structure or foundation. No heavy hauling or compacting equipment shall be permitted closer than 3 feet to any structure or foundation during backfilling. In all areas closer than 3 feet, or where workspaces otherwise limited, smaller specialty equipment such as vibratory plates, grammars, or pneumatic tampers shall be used for densification.
Where a large number of lifts are required to complete a backfill operation and the elapsed time between placement is large, the surface of each lift should be sloped slightly to facilitate drainage and prevent ponding on the fill.
----COMPACTED Fill _.--------~,c;....., __ _.
r ,op.SC)ll, OOlLUVIUM --I
-ANDW1EATHERED --BEDROCK -_ ....... ;;.._ ___ ...11 --,..., -
----
UNWEATHERIED BEDROCK
-0 IGINAl
_,,.GROUND
OVERE:X.CAVATE:
AND REGRADE
Guide Specifications for Earthwork
6
PREPARATION OF AREAS TO BE FILLED
Clearing and Grubbing
General
Vegetation, such as brush, grass, roots, and other deleterious material shall be sufficiently
removed and properly disposed of in a method acceptable to the Owner, governing agencies
and the GEOR.
Care should be taken not to encroach upon or otherwise damage native and/or historic trees
designated by the Owner or appropriate agencies to remain. Pavements, flatwork, or other
construction should not extend under the "drip line" of designated trees to remain.
Clearing shall consist of complete removal above the ground surface of trees, stumps, brush,
vegetation, man-made structures, and similar debris. Grubbing shall consist of removal of
stumps, roots, varied logs, and other unsuitable material. In particular, roots and other
projections exceeding 1½ inches diameter shall be removed to a depth of 3 feet below ground
surface.
Borrow areas shall be grubbed to the extent necessary to provide suitable fill materials.
The GEOR shall evaluate the extent of these removals depending on specific site conditions.
Earth fill material shall not contain more than 3% of organic materials (by dry weight: ASTM D
2974-00). Nesting of the organic materials shall not be allowed.
Hazardous or Regulated Materials
If potentially hazardous materials are encountered, the Contractor shall stop work in the affected
area, and a hazardous material specialist shall be informed immediately for proper evaluation
and handling of these materials prior to continuing to work in that area.
As presently defined by the State of California, most refined petroleum products (gasoline,
diesel fuel, motor oil, grease, coolant, etc.) have chemical constituents that are considered to be
hazardous waste. As such, the indiscriminate dumping or spillage of these fluids onto the
ground may constitute a misdemeanor, punishable by fines and/or imprisonment, and shall not
be allowed.
Benching Sloped Ground
Areas where the original ground is inclined steeper than 5:1 (horizontal: vertical) or where
recommended by the GEOR, the original ground should be benched in accordance with Figure
2 (following page).
As may be seen by review of Figure 2, the lowest bench or key shall be a minimum of 15 feet
wide and at least 2 feet deep into competent material as evaluated by the GEOR. Other
benches shall be excavated a minimum height of 4 feet into competent material or as otherwise
recommended by the GEOR.
Guide Specifications for Earthwork
7
Fill placed on ground sloping flatter than 5:1 (i.e., at less than 20% grade) shall also be benched
or otherwise over-excavated to provide a flat subgrade for the fill.
Figure 2. Benching for Ground to Be Filled
Processing
Existing ground that has been declared satisfactory for support of fill by the GEOR shall be
scarified to a minimum depth of 6 inches. Existing ground that is not satisfactory shall be over-
excavated as specified in the following subsection.
Scarification shall continue until soils are broken down and free of large clay lumps or clods and
the working surface is reasonably uniform, flat, and free of uneven features that would inhibit
uniform compaction. Thereafter, the scarified soil should be moisture conditioned to at or above
its optimum moisture content and compacted as detailed under Fill Placement and Compaction
on page 9 of this appendix.
Over-Excavation
In addition to removals and over-excavations recommended in the geotechnical report and the
grading plan, soft, loose, dry, saturated, spongy, organic-rich, highly fractured, or otherwise
unsuitable ground shall be over-excavated to competent ground as evaluated by the GEOR
during grading.
All undocumented fill under proposed structure footprint(s) should be excavated as described in
the geotechnical report.
FILLSLOPE -
SIURFAC11: OF FIIRM
EARTH MATERIAL
16' MIN. (INCLI 'BD 2% MlN. INTO S1 OPE)
Guide Specifications for Earthwork
8
FILLING
Evaluation/Acceptance of Fill Areas
All areas to receive fill shall be observed, mapped and/or tested, and documented with
elevations prior to being accepted by the GEOR as suitable to receive fill.
The Contractor shall obtain approval from the GEOR prior to fill placement. A licensed surveyor
shall provide the survey control for determining elevations of processed areas, keys and
benches.
Select Fill
All engineered fill should conform to the criteria for materials, placement, compaction, and timely
construction identified for Select Fill in the attached geotechnical report.
Soils of poor quality, such as those with unacceptable gradation, high expansion potential, or
low strength shall be placed in areas acceptable to the GEOR or mixed with other soils to
achieve satisfactory fill material.
Fill Slopes
Soil fill slopes must be properly compacted. In order to achieve this end, fill slopes should be
developed by one of the two means described below, or by other methods producing
satisfactory results acceptable to the GEOR.
1. Overbuild. The slope may be overbuilt by at least 3 feet and then cut to the design grade. Upon completion of grading, relative compaction of the fill, out to the slope face,
shall be at least 90% of the ASTM D 1557 laboratory maximum density.
2. ‘Back Rolling’. Slope faces may be back rolled with a heavy-duty loaded vibratory
sheepsfoot roller at maximum 4-foot height intervals. Upon completion, the slopes should then be tracked walked with a D8 dozer or similar equipment such that the dozer tracks cover all sloped surfaces at least twice. Upon completion of grading, relative
compaction of the fill, out to the slope face, shall be at least 90% of the ASTM D 1557 laboratory maximum density.
Oversize
Oversize material defined as rock, or other irreducible material with a maximum dimension
greater than 6 inches, shall not be buried or placed in fill unless location, materials, and
placement methods are specifically accepted by the GEOR.
Placement operations shall be such that nesting of oversized material does not occur and such
that oversize material is completely surrounded by compacted or densified fill. Oversize material
shall not be placed within 10 feet measured vertically from finish grade, or within 2 feet of future utilities or underground construction.
Guide Specifications for Earthwork
9
Import
If importing of fill material is required for grading, proposed import material shall meet the
requirements for Select Fill identified in the attached geotechnical report.
A representative sample of a potential import source shall be given to the GEOR at least four
full working days before importing begins, so that suitability of this import material can be
determined and appropriate tests performed.
Fill Placement and Compaction
Moisture Conditioning
Approved Select Fill (see the attached geotechnical report) shall be watered, dried back, and
blended and/or mixed, as necessary to attain a relatively uniform moisture content at or slightly
over optimum.
Maximum density and optimum soil moisture content tests shall be performed in accordance
with the American Society of Testing and Materials (ASTM) Test Method D 1557.
Placement
Loose zones or areas disturbed by excavation should be recompacted to at least 90% relative
compaction after ASTM D1557 (the ‘Modified Proctor’). Thereafter, exposed surface of the area
to receive Select Fill should be examined by the GEOR to identify any localized soft, yielding, or
otherwise unsuitable materials. Proof rolling may be used to quickly identify loose/soft or
yielding zones.
Approved Select Fill (see the attached geotechnical report) shall be placed in areas prepared to
receive fill, in near-horizontal layers not exceeding 8 inches in loose thickness.
The GEOR may accept thicker layers if testing indicates the grading procedures can adequately
compact the thicker layers. Each layer shall be spread evenly and mixed thoroughly to attain
relative uniformity of material and moisture throughout.
Compaction
After each layer has been moisture-conditioned, mixed, and evenly spread, each layer shall be
uniformly compacted to not less than 90% of the maximum dry density as determined by ASTM
Test Method D 1557 (the ‘modified Proctor’).
In some cases (for example, pavement base courses or certain subgrades) structural fill may be
specified to be uniformly compacted to at least 95% of the ASTM D 1557 laboratory maximum
dry density.
Compaction equipment shall be adequately sized and be either specifically designed for soil
compaction or of proven reliability to efficiently achieve the specified level of compaction with
uniformity.
Guide Specifications for Earthwork
10
Compaction Testing
General
Field-tests for moisture content and relative compaction of the fill soils shall be performed by the
GEOR. Location and frequency of tests shall be at the discretion of the GEOR’s field
representative(s) based on field conditions encountered.
Compaction test locations will not necessarily be selected on a random basis. Test locations
shall be selected to verify adequacy of compaction levels in areas that are judged to be prone to
inadequate compaction (such as close to slope faces, within trenches, etc.).
Compaction Test Locations
The GEOR shall document the approximate elevation and horizontal coordinates of each
density test location.
Adequate grade stakes shall be provided by the Contractor. The Contractor shall coordinate
with the Contractor’s surveyor to assure that sufficient grade stakes are established so that the
GEOR can determine the test locations with sufficient accuracy.
Protection of Work
Protection of ongoing and completed earthwork is the sole responsibility of the Contractor. In
particular, the Contractor shall properly grade all earthwork to provide positive drainage and
prevent ponding of water. Related thereto, drainage of surface water shall be controlled to avoid
damage to adjoining properties or to finished work on the site. The Contractor shall take
measures as appropriate to prevent erosion of newly graded areas until such time as permanent
drainage and erosion control features have been installed.
Structures or pavements atop engineered fill should be constructed as quickly as possible
following approval of fill by the GEOR. The Contractor is responsible for maintaining the
engineered fill in its approved condition (i.e., moist, free of water, debris, etc.) until foundations
or pavements are constructed.
The approval of any earthwork is contingent on proper maintenance of the completed work prior
to construction of any foundations, slabs, or other structures. Earthwork can be damaged by
construction activities and exposure to weather (i.e., disturbance, drying, wetting, etc.).
TRENCH BACKFILLS
Safety
The Contractor shall follow all OSHA and Cal/OSHA requirements for safety of trench
excavations. The Contractor is solely responsible for the safety of all excavations.
Guide Specifications for Earthwork
11
Bedding and Backfill
General
All utility trench bedding and backfill shall be performed in accordance with applicable provisions
of the most current edition of the Standard Specifications for Public Works Construction (‘Green
Book’).
Bedding
Unless otherwise specified, bedding material for pipes shall have a Sand Equivalent (SE)
greater than 30 (SE > 30). Bedding shall be placed to 1-foot over the top of the conduit, and
densified by jetting in areas of granular soils, if allowed by the permitting agency. Any jetting of
the bedding around the conduits shall be observed by the GEOR.
In the event a sand bedding is not utilized, the pipe-bedding zone should be backfilled with
Controlled Low Strength Material (CLSM) consisting of at least one sack of Portland cement per
cubic-yard of sand, and conforming to the requirements of the most current edition of Standard
Specifications for Public Works Construction (Green Book).
Placement of the sand bedding shall be observed by the GEOR.
Backfill
Backfill over the bedding zone shall conform to the requirements for Select Fill identified in the attached geotechnical report, extending this Select Fill from the top of the bedding material.
Prior to compaction, Select Fill should be moisture conditioning to at least 2% above the
optimum moisture content. Select Fill should be spread in loose lifts no thicker than the ability of
the compaction equipment to thoroughly densify the lift. For most smaller, hand-operated, or
remotely controlled equipment (tampers, walk behind compactors, etc.), lift thickness will be
limited to on the order of 4 inches or less.
Backfill above the pipe zone shall not be jetted. All backfill above the pipe zone (bedding) shall
be observed and tested by the GEOR.
CERTIFICATIONS AND FINAL REPORTING
Certifications
As work progresses, the GEOR shall furnish the Owner certifications as may be necessary
documenting that various elements of the work (for example, building lots and/or building pads)
from a geotechnical standpoint.
Such certifications will be reliant upon survey information provided by the Contractor that
establishes that the relevant earthwork has been graded to within 0.1-foot vertically of the
elevation shown on the grading plan and that the tops and toes of all slopes are within 0.5 feet
horizontally of the position shown on the grading plans.
Guide Specifications for Earthwork
12
Project Closure
Following the conclusion of all work, the GEOR will be responsible for preparation of a final as-
graded soil and geologic report that satisfies the documentation required by the appropriate
building official(s).
The final as-graded soil and geologic report will be prepared and signed by a California-licensed
Civil Engineer experienced in geotechnical engineering and by a California-licensed Certified
Engineering Geologist. The report will address the consistency of subsurface materials
disclosed by the earthwork were consistent with those identified by the geotechnical
investigation, discussing variances thereto. As supported by records of all testing of earthwork,
the report will address conformance of the earthwork with the recommendations of the attached
geotechnical investigation and with these Guide Specifications.