HomeMy WebLinkAboutPD 2021-0004; NORTH COUNTY ACADEMY; GEOTECHNICAL INVESTIGATION; 2020-12-07k. N
erthnfrI In
North County Academ
Ow
North County Academy
1640 Magnolia Avenue
Carlsbad, CA 92008
NOVA Project 2020187
December 7, 2020
San Diego
858.292.7
944 Calle A
San Clemente
P: 949388.77
0A A GEOTECHNICAL
AM
131
MATERIALS
NOVA SPECIAL INSPECTION DVBE • SBE. SDVOSB • SLBE
Carlsbad Unified School District December 7, 2020
6225 El Camino Real NOVA Project 2020187
Carlsbad, CA 92009
Attention: Derrick Anderson
Subject: Report
Geotechnical Investigation
Proposed Portable Classrooms
North County Academy
1640 Magnolia Avenue, Carlsbad, California
Dear Mr. Anderson:
NOVA Services, Inc. (NOVA) is pleased to present herewith its report of a geotechnical
investigation for the subject development. The work reported herein was completed by NOVA
for the Carlsbad Unified School District (CUSD) in accordance with NOVA's proposal dated
October 12, 2020.
NOVA appreciates the opportunity to be of service on this most interesting project. Should you
have any questions regarding this report or other matters, please contact the undersigned at
858.292.7570.
Sincerely,
NOVA Services, Inc.
Wail Mokhtar
Senior Project Manager
Melissa Stayner, PG, CEG
Senior Engineering Geologist
1'k
J hn F. O'Brien, PE, GE
P incipal Geotechnical Engineer
)., Hillary A. Price
Senior Staff Geologist
4373 Viewridge Avenue, Suite B www.usaWnova.com 944 CaUe Amanecer, Suite F
San Diego, CA 92123 San Clemonte, CA 92673
P: 858.292.7575 P: 949.388.7710
kc Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
1316, NOVA Project 2020187
NOVA December 7, 2020
Report j
Geotechnical
North County Academy, 1640 MagnoliaFLn ,l!I:
Carlsbad, California
Table of Contents
iL1 INTRODUCTION I. ... . .. .. mm.
1.1 Terms of Reference I
1.2 Objectives, Scope, and Limitations of Work ..................................................... I
1.2.1 Objectives .................................................................................................................................. I
1.2.2 Scope ........................................................................................................................................2
1.2.3 Limitations .................................................................................................................................2
1.3 Understood Use of This Report .........................................................................3
1.4 Report Organization............................................................................................3
2.0 PROJECT 4
2.1 Location ...............................................................................................................4
2.2 Site Description...................................................................................................4
2.2.1 Current Site Development ... ................................................... ............................. ...................... 4
2.2.2 Historic Site Use........................................................................................................................5
2.3 Planned Development.........................................................................................5
2.3.1 General.. .............. .............................. ................................... ............................. ......... ............... 5
2.3.2 Structural ...... .......... ............... .............. ................................... .......... .................... ..................... 5
2.3.3 Civil .... ........... ............... ....................................... ................................................................. ...... 5
11 11IjI:411zl i.X.11
3.1 General.................................................................................................................7
3.2 Engineering Borings...........................................................................................8
3.2.1 General .............................................................................................................. .................... .... 8
3.2.2 Logging and Sampling ..............................................................................................................8
3.23 Closure ........................................... ...... ... ............... .............................. .....................................
9
i of v
Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California 411111k NOVA Project 2020187
NOVA. December 7, 2020
3.3 Percolation Testing.............................................................................................9
3.3.1 General... .............. ... ............ ............................................................................... ....................... 9
3.3.2 Drilling .......................................................................................................................................9
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
4.0 SITE CONDITIONS ..........
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
42.4 Surface Water .........................................................................................................................17
-1 Tfs .1t.Ie1I.r.11wil iI1iIeJTY 4'R..f:3
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
5.4.2 Flood .......................................................................................................................................23
5.4.3 Tsunami ............... .................... .............. .......... .......... ............... .......... ............................. .. ...... 23
5.4.4 Seiche .....................................................................................................................................24
ii of v
sA Report of Geotechnical Investigation
'
A
Proposed Portable Classrooms, North County Academy, Carlsbad, California
1111. NOVA Project 2020187
NOVA, December 7, 2020
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 Foundation Preparation ....................................................... ............................................ ...... ..30
6.5 Support for the Modules...................................................................................31
6.5.1 General ................................. ............................. ................ ...................................... ............ .... 31
6.5.2 Ground Supported Slab ..........................................................................................................31
6.5.3 Foundations for a Handicapped Ramp ...................................................................................32
6.5.4 Resistance to Lateral Loads .................................................................... ................................ 32
6.5.5 Settlement ...............................................................................................................................32
6.6 Miscellaneous Site Structures .........................................................................32
6.6.1 Signs and Light Poles .............................................................................................................32
6.6.2 Equipment Pads ....................................... ............................................................................... 32
6.6.3 Shade Structure ......................................................................................................................33
6.7 Surfacing for the Play Area ..............................................................................33
7.0 STORM WATER INFILTRATION...................................................... 35
7.1 Overview ............................................................................................................35
7.2 Infiltration Rate..................................................................................................35
7.3 Review of Geotechnical Feasibility Criteria....................................................36
7.3.1 Overview .................................................................................................................................36
7.3.2 Soil and Geologic Conditions..................................................................................................36
7.33 Settlement and Volume Change .............................................................................................36
7.3.4 Slope Stability..........................................................................................................................37
7.3.5 Utilities ......................................................... ........ .............................................. ................... ...37
iii of v
Report of Geotechnical Investigation
lal
Proposed Portable Classrooms, North County Academy, Carlsbad, California
NOVA Project 2020187
NOVA December 7, 2020
7.3.6 Groundwater Mounding ................................................................................................ ....... .... 37
7.3.7 Retaining Walls and Foundations ...........................................................................................37
7.3.8 Other .......................................................................................................................................37
7.4 Preliminary Recommendation for Infiltration..................................................37
8.0 PAVEMENTS ..i;]
8.1 Overview............................................................................................................38
8.1.1 General ... .............................. .......... .......... .............. .. ............ ...... .. ......... ....................... ........... 38
8.1.2 Design to Limit Infiltration .......... .............. .. ......... .... .. ......... .............. ..... ............... .................... 38
8.1.3 Maintenance ........................................................ .................................................... ............ .....38
8.1 .4 Review and Surveillance ...................... ........... ........................................ ................................ 38
8.2 Subgrade Preparation.......................................................................................39
8.2.1 General ............................................. ................... ............... ............... ...................................... 39
8.2.2 Proof-Rolling ........................................................................................................... ................. 39
8.2.3 Timely Base Course Construction ....................... ... ......... ...... ................. .......... .. ... ..... ............. 39
8.3 Flexible Pavements...........................................................................................39
8.4 Rigid Pavements ...............................................................................................40
8.4.1 General ......... .................................................................................... ....................................... 40
8.4.2 Joints ...... ................... ........................................................ .................................. .................... 40
9.0 REFERENCES ........................... rl.
9.1 Site Specific.......................................................................................................41
9.2 Design ................................................................................................................41
9.3 Geologic and Site Setting.................................................................................42
Plates
Plate 1 Subsurface Exploration Map
List of Appendices
Appendix A Use of the Geotechnical Report
Appendix B Logs of Borings
Appendix C Records of Laboratory Testing
Appendix 0 Infiltration Feasibility Documents
Appendix E Guide Specifications for Earthwork
iv of v
& Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
A NOVA Project 2020187
N0 VA. December 7, 2020
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 Soil Gradation Testing
Table 3-4. Abstract of the Maximum Density and Optimum Moisture Testing
Table 3-5. Abstract of Chemical 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 7-1. Infiltration Rates Determined by Percolation Testing
Table 8-1. Preliminary Recommendations for Flexible Pavements
Table 8-2. Recommended Concrete Requirements
List of Figures
Figure 1-1. Vicinity Map
Figure 2-1. Site Location and Limits
Figure 2-2. Conceptual Site Development Plan
Figure 2-3. Typical Pier Designs for Building Modules
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 of 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
v of v
1-5 Report of Geotechnical Investigation
Proposed Portable Cassroorns, North County Academy, Carlsbad, California
4 NOVA Project 2020187
December 7, 2020
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 NOVAs 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
1.2 Objectives, Scope, and Limitations of Work
121 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 planning-
stage recommendations for development of stormwater infiltration Best Management
Practices (stormwater BMPs').
Report of Geotechnical Investigation
,
daA
Proposed Portable Classrooms, North County Academy, Carlsbad, California
A NOVA Project 2020187
NOVA December 7, 2020
1.2.2 Scope
NOVA undertook the task-based scope of work described below to address the above objectives.
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.
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, Planning Phase 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 testing
was conducted in accordance with the requirements of the City of Carlsbad.
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.
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.
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
2
Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
A NOVA Project 2020187
NOVA December 7, 2020
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.
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 four 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.
41
Report of Geotechnical Investigation
Proposed Portable Classrooms. North County Academy, Carlsbad, California
il NOVA Project 2020187
N () \'A December 7, 2020
t1i *3I'IIII 0I :i'Jii.ii
2.1 Location
The approximately 0.25-acre site of investigation is nominally located at 1640 Magnolia Avenue
in Carlsbad, California (ARN 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
(following page) depicts these limits on a recent aerial image.
cation and
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 fiat. Ground
elevations range from about +158 feet mean sea level (msl) in the southwest corner to about
+163 feet msl along the eastern boundary.
4
Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
4416, NOVA Project 2020187
N OVA. December 7, 2020
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 a current
topographic survey of the project area (reference, Topographic Survey Map-North County
Academy School, Pasco Laret Suitor & Associates, August 14, 2020, hereinafter 'PLSA 2020').
ASDG 2020 depicts planning for three modular classrooms on concrete foundations, playground
equipment, a shade structure, and a stormwater BMP facility. Figure 2-2 (following page)
reproduces ASDG 2020.
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.
The modules are lightweight structures. Such structures are commonly supported by a series of
piers that bear on the ground or a firm foundation. Figure 2-3 (following page) depicts examples
of mechanical piers commonly used to support the modules.
2.3.3 Civil
No documentation is available that depicts planning for civil development of the project.
Based upon experience with similar projects, NOVA expects that the 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.
Recommendations for earthwork are discussed in detail in Section 6.
5
Nil
Ropoo of Gcotnchnica I Ifvestigat on
Piupued Puttauiu Ctassroums, North County Academy. Carlsbad, Cato
NOVA Project 2020
Decohei 7 --
Figure 2-2. Conceptual Site Development Plan
(source: ASDG 2020)
Tf-
s H
FE SEE
• PAt _,J.00 ..iccw . 9
. n. . p •
'5- - 5-
-
- PtCAL PE' e --
- -FIER - -
Finure 2-3 Tvnicl Pier Desions for the Modules
#& Report of Geotechnical Investigation
Proposed Portable Classrooms. North County Academy, Carlsbad, California
A W11 NOVA Project 2020187
1 December 7, 2020
3.0 SUBSURFACE EXPLORATION AND LABORATORY TESTING
3.1 General
NOVA's subsurface exploration included four (4) engineering borings (referenced as B-i
through 13-4) and two (2) planning phase percolation test borings ('P-l' 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 i, provided
immediately following the text of this report, shows the location of this work in larger scale.
r
Qop
B-2
H B-3
*4 KEY To SYMBOLS
Qop
B-4
H I l-CHNII A
RCCATK)N ii
B-i ,
H
çp B4
N
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 the related laboratory testing.
7
Report of Seotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
4 NOVA Project 2020187
NOVA December 7, 2020
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
Approx. Total Depth Elevation at Approx. Depth Approx. Depth to Boring Ground Below Completion to Formation Groundwater Reference Surface Elev. Ground (feet, msl) (feet) (feet) (feet, msl) Surface (feet)
B-i +162 16.5 +145.5 1.0 Not Encountered
6-2 +160 21.5 +138.5 1.0 Not Encountered
B-3 +163 21.5 +141.5 1.0 Not Encountered
6-4 +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.
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.
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.
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.
if Report of Seotechnical Investigation
PDpcsed Fortah Classrooms. \orth County Academy. Carlsbad, Cafornia
A NOVA Project 2020187
UVN December 7, 2020
F gure 3-2. Drilling Oerations November 3, 2020
3.2.3 Closure
On completion, the Lorings were backfilled wlh soil cuttings. The area of eacr boring was
cleaned ard left as close as practical to its orinal condition
3.3 Percolatior Testing
3.3. 1 Genera
NOVA d rected the excavEtion and construction of two (2) çercolation test wells following the
planning phase reco-nmerdatiois for percola:ion testing pre;ented in the Cit of Carlsbad BMP
Design Manual, 2016 editijn. In accordance with this mant, percolation rates were later
converted :o infiltratii rates. Detailed discussion of infiltrai c n rates and reccn mend ations are
presentcd in Secticn 7. The percolation test locations are shDwn on Figure 3-1,
3.3.2 Drilling
The boriigs for the wells were crilled with an 3-inch hollow 3-.em auger to a depth of 5 feet bgs.
Field murements were taken to confirm th3t the borings were excavated to approximately 8
I
Report of Seotechnical lnvestigatH
Proposed Portable Classrooms. North County Academy. Carlsbad, Cafo
FULla NOVA Project 2020
Deco 05cr?
inches in diameter. The borings were logged by a NOVA geoioqst, who observed and recorded
exposed soil cuttings and the boring condiboru.
3.3.3 Conversion to Percolation We/i
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 3/4-inch gravel on the bottom, then
extending 3-inch diameter Schedule 40 perforated PVC pipe to the ground surface. The '/,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.
Fgure 3-3. Percolation Test Well P2, 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.
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
a
A Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
4 . NOVA Project 2020187
NOVA December 7, 2020
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 abstracts the results of the percolation testing.
Table 3-2. Abstract of the Percolation Testing
Percolation Total Percolation Infiltration Infiltration Boring Elevation Test Depth Rate Subsurface Rate Rate Reference (feet, msl) 1 Elevation (feet) 1
. (mm/in) Unit Tested' (in/hr) (in/hr, FS=2)4 (feet,_msl)
P-i +162 5 +157 83 Qop 0.03 0.02
P-2 +163 5 +158 50 Qop 0.06 0.03
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.
34 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 ('USGS,' ASTM 0 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.
11
Report of Geotechñical Investigation
Proposed Portable Classrooms. North County Academy, Carlsbad, California AA NOVA Project 2020187
Nfl VA 2I I December 7, 2020
Table 3-3. Abstract of the Moisture-Density Testing, ASTM D1557
Boring Depth Soil I Maximum Optimum Moisture
(feet) Description Dry Density Content (/o)
B-I 2 -5 Orange Brown Silty Sand 135.1 8.1
B-2 I - 5 Orange Brown Silty 132.5 7.9 SandlClayey_Sand
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 (feet)
Classification
after
ASTM D2488 Boring Depth
B-I 2-5 35 SM
B-i 5 47 SM
B-i 7-10 44 SM
B-I 7.5 31 SM
B-I 10 26 Sc
B-3 2.5 40 SM
B-3 5 55 SM/ML
6-3 7.5 29 SM
B-3 10 26 SM
6-3 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 (El),
after ASTM D4829. The sample indicated El = 1; characteristic of a soil with Very Low
expansion potential.
3.4.5 P-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
12
Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
At NOVA Project 2020187
NOVA. December 7, 2020
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 02844 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 Sulfates Chlorides
Resistivity - Depth pH / Boring (feet) (Ohm-cm) ppm /o PPM
- B-I I 2-5 I 8.6 3300 I 39 I 0.004 32 0.003
13
Report of Geotechnical Investigation
AR Proposed Portable Classrooms, North County Academy, Carlsbad, California
A NOVA Project 2020187
NOVA. December 7, 2020
4.0 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
non-marine 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 which characterize the landforms in western
San Diego County.
4.1.2 Site Specific
The site area is underlain by non-marine 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.
14
Report of Geotechnical Investigation
Proposed Portable Classrooms. North County Academy. Carlsbad, California ri NOVA Project 2020187
December 7, 2020
KEY TO SYMBOLS
[~~P767 ~V07PQ T
Qop2 J [dvO~P 2 UN7 r'Q
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.
15
Report of Geotechrdcal Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, Cafornm
4 NOVA Project 2020187
December 7. 2020
'1 Ali
5 -
,
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.
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.
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 (EN', 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.
in
Report of Geotochnic.I .nvestigation
Frop ed Fotobie Classrooms. Ncth County Academy. Car sbad, Caforna
NOVA roect 2020187
NO VIA D€ cember 7, 2020
a
4,2.3 Groundwater
Groundwater was not encountered n the bcdrgs, trough near the bottom of the borings, the
material became wet. During back.: -ound reiew, there were no nearby well data to estimate
g'oundwater level at the site. Baser on bcrhgs performed for This investigation, grourdwater
ill not be a constraint to developrent.
4 2.4 Surface Water
No surface water was evident on t site at the time of NOVA's work. At the time of NOVA's
sibsurface exploration, there were no eidt signs of recent problems with surface water (i.e.,
n evidence of staining, erosion, seeps, 3prrgs, etc.).
17
sk Report of Seotechnieal Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
A31 NOVA Project 2020187
NOVA, December T. 2020
LI' *YA I 4''ke] Zc1 .] !I.Ie1 [Ie11 'i1II I Ici
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.
iE]
Report of Geotechnical Investigation
P upuSea Pocahie ssrccms, Noch County Academy, Cahshad, Caforna
ii kik NOVA Project 2020187
December 7, 2020
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'.
19
A Report of Geotechnical Investigation
AR
I
Proposed Portable Classrooms, North County Academy, Carlsbad, Caiifornm
4 NOVA Project 2020187
\O \A December 7, 2020
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.
,ø 's... •. 5/. I - ft
I
KEY TO SYMBOLS
If A A T Wf I A3Z)5t I 1) 5UrPTflHTY AM A LAD1JDES
ç
/
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.
20
GALIk Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
4 , NOVA Project 2020187
NOVA December 7, 2020
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.
53.2 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.
53.3 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.
21
Report of Geotechnkal Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
A NOVA Project 2020187
Nfl VA December 7, 2020
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 ('El', after ASTM D 4829). El 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 El.
Expansion Index
JEJJ, ASTM D 4829
Expansion Potential,
ASTM P 4829
Expansion Classification,
2013 CBC
0 to 20 Very Low Non-Expansive
21 to 50 Low
Expansive
Very high
51 to 90 Medium
91 to 130 High
>130
Neither the Unit I topsoil nor the Unit 2 old paralic deposits are expansive.
5.3.4 Hydro-Collapsible Soils
Hydro-collapsible soils are common in the and 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.
22
YIA Report of Geotechncal lnvesdgadir
Proposed Portable Classrooms, Noh County Academy, Carlsbad, Caior
NOVA Project 20201
Deernhe 7.
54 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 macnina by FEMA of the site area.
Finiir -3. Find Mnninri of thp Sitc? Arc
(source: FEMA Flood Map 0607300762G, 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.
23
Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, Caifornia
A NOVA Project 2020187
NOVA. December 7, 2020
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.
24
gAA ~ Report of Geotechnical Investigation
2
Proposed Portable Classrooms, North County Academy, Carlsbad, California A 16, NOVA Project 2020187
NOVA. December 7, 2020
Js i I: IY'L.1 i 'i .iui I liii
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.
25
Report of Geotechncal Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
131 NOVA Project 2020187
Nfl VA .2. .% December 7 2020
NOVA has a lot of experience with the old paratic 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, F, was taken from Table 11.4-2, and SMI and SDI 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 Ill.
Table 6-1. Seismic Design Parameters, ASCE 7-16
Parameter Value
Soil Class 0
Risk Category Ill
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, S5 1.038
Mapped One-Second Period Spectral Acceleration, S 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, S01 0.482
Site Adjusted Peak Ground Acceleration (PGAM) 0.522
Source: OSHPD Seismic Design Maps, found at www.seismicmaps.org; Value of Fwas 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.
9.1
Report of Seotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
'4106, NOVA Project 2020187
Mfl\JA .L..I December 7, 2020
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 (p). 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 O-cm
0 to 2,000
Qualitative Corrosion
Potential
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:
27
Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
4 NOVA Project 2020187
NOVA
I December 7, 2020
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 (ACt) 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 ACt guidance.
Table 6-4. Exposure Categories and Requirements for Water-Soluble Sulfates
Exposure
Category Class Water-Soluble
Sulfate (SO4) In
Soil
Cement Type
(ASTM C150)
Max Water-
Cement Ratio
Min.f'
(psi)
Not Applicable SO SO4 < 0.10 - - -
Moderate SI 0.10 SO4 < 0.20 Il 0.50 4,000
Severe S2 0.20 :5 SO4 2.00 V 0.45 41500
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."
W.
Report of Geotechnical Investigation
IN Proposed Portable Classrooms, North County Academy, Carlsbad, California
131 NOVA Project 2020187
NOVA December 7, 2020
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
Materials
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 1/4 inches in size,
classified as GW, GM, GC, SW, SM, after ASTM D2487;
maximum particle size of 2 inches, and
expansion index (El) of less than 20 (i.e., El <20, after ASTM D 4829).
Some of Unit I 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.
Placement
The exposed surface of the area to receive Select Fill should be examined by a
NOVA representative to identify any localized soft, yielding, or otherwise unsuitable
materials. Loose zones or areas disturbed by excavation should be recompacted to
at least 90% relative compaction after ASTM Dl 557 (the 'Modified Proctor').
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 self-propelled construction equipment adaptable to this site, this criterion will
29
Report of Geotechnical Investigation
AM
Proposed Portable Classrooms, North County Academy, Carlsbad, California
NOVA Project 2020187
NOVA. December 7, 2020
limit loose lifts to on the order of 6 inches or less. Lift thickness for hand-operated
equipment (tampers, walked behind compactors, etc.) will be limited to on the order
of 4 inches or less.
Compaction
Loose lifts of moisture-conditioned Select Fill should be densified to at least 90%
relative compaction after ASTM Dl 557.
The Select Fill will likely best be densified by vibratory equipment. A vibratory padfoot
roller, consisting of a steel drum with protruding feet, will likely work well. Adequate
compaction will be demonstrated as the roller 'walks out' of the lift being compacted.
Timely Construction
Structures or pavements atop approved Select Fill for should be constructed as
quickly as possible following approval. The Contractor is responsible for maintaining
the Select Fill in its approved condition (i.e., moist, free of water, debris, etc.) until
foundations or pavements are constructed.
6.4.4 Foundation Preparation
Pad for the New Modules
Existing Unit 2 paralic deposits should be prepared using the stepwise procedure
described below. The foundation preparation area should include the building pad
and extend to 3 feet outside the limits of the pad.
I. Step 1, Excavate and Stage. The 12 inches beneath the base of
foundations/floor slabs should be removed and staged for later replacement.
Step 2, Scarify/Moisture Condition. The surface exposed by Step I should be
scarified to a depth of 12 inches, moisture conditioned to above the optimum
moisture, then compacted to at least 90% relative compaction after ASTM
D1557.
Step 3, Replacement. The soils staged by Step I should be moisture
conditioned to 2% above the optimum moisture content and replaced at 90%
relative compaction after ASTM D 1557.
Flatwork
Non-structural areas outside of building pads that include sidewalks and other
flatwork, etc., should be over-excavated to remove the Unit I topsoil. Soils disturbed
during this operation should be redensified.
30
I AR
Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
P '410 NOVA Project 2020187
NOVA. December 7, 2020
6.5 SUpport for the Modules
6.5.1 General
It is expected that the modules may be in place for up to several years, until permanent facilities
can be developed. The Unit 2 paralic deposits are generally of high strength and low
compressibility relative to development of these planned lighter modules.
Ground supported piers may be designed for an allowable contact stress of 1,200 psf. This
value may be increased by 1/3 for transient loads such as wind and seismic.
6.5.2 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.
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 % the slab thickness, as depicted
in Figure 6-1.
Sawcut
/4Ornin4
Inducederack k
Sawed contraction joint
Figure 6-1. Sawed Contraction Joint
31
Report of Geotechnical Investigation
0 Proposed Portable Classrooms, North County Academy, Carlsbad, California
A NOVA Project 2020187
NOVA. December 7, 2020
6.5.3 Foundations for a Handicapped Ramp
Isolated foundations for a ramp for handicap access should be established within the Unit 2
paralic deposits on ground prepared as recommended in Section 6.3. Treated wood or concrete
foundations should be set at a minimum of 6 inches below surrounding ground, a minimum of
12 inches in smallest plan dimension.
Founded as such, foundations may be designed for an allowable contact stress of 1,200 psf.
This value may be increased by % for transient loads such as wind and seismic.
6.5.4 Resistance to Lateral Loads
Lateral loads to foundations may be resisted by the interface shear between the soil and the
base of the pad. A coefficient of friction of 0.35 between the soil and concrete.
6.5.5 Settlement
Foundations developed as described above will settle imperceptibly, less than 0.2-inch, with
angular distortion less than 1:600 due to differential settlement between adjacent unevenly
loaded areas. Soils will settle elastically, with movement occurring approximately as load is
applied.
6.6 Miscellaneous Site Structures
6.6.1 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
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.
6.6.2 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.
32
Ak
Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
'4116. NOVA Project 2020187
NOVA December 7. 2020
Founded as described above, ground supported equipment and related will have an allowable
bearing capacity (q) of qa = 1,500 psf.
6.6.3 Shade Structure
No information is available regarding planning for a shade structure. In usual case, such
structures are supported by a central column. Such columns may be set into shallow
foundations bearing on the formation soils. 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
Footings for a shade structure embedded a minimum of 2 feet below surrounding ground and
with the minimum smallest dimension of 30 inches may bear on the Unit 2 paralic deposits at qa
= 2,500 psf. This value may be increased by one third 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 anger embedment.
6.7 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.
33
Report of Seotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
12 NOVA Project 2020187
NOVA December 7, 2020
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 the
general case, 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.
Figure 6-4. Layered Cushioning Media
(source: U.S. Consumer Product Safety Commission,
Public Playground Safety Handbook, December 2015)
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 Unit I fill and layers above it 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.
01
sk Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
.426. NOVA Project 2020187
NOVA ' V December 7, 2020
Y.JL.'i I 1 1I I III t.I I I.)
7.1 Overview
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 I 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
Approximate Depth of Approximate Infiltration Design
Boring! Ground Elevation Test Test Elevation Rate Infiltration Rate
(feet. ms]) (feet) (feet, msl) (inches/hour) (in/hour, FS2*)
P-1 +162 5 +157 0.03 0.02
P-2 +163 5 +158 0.06 0.03
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, at least FS = 2 in local practice,
considers the nature and variability of subsurface materials, as well as the natural tendency of
35
Report of Seotechnical Investigation b Proposed Portable Classrooms, North County Academy, Carlsbad, California
4 NOVA Project 2020187
NOVA. December 7, 2020
infiltration structures to become less efficient with time. The calculated infiltration rates after
applying ES = 2 is I = 0.02 and 0.03 inches per hour for P-i and P-2, respectively.
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.
0.2.1 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.
Unit 1, Topsoil. The site is covered by a layer of topsoil that is about i-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.
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.
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.
36
Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
A NOVA Project 2020187
NOVA. December 7, 2020
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 Preliminary Recommendation for Infiltration
In consideration of the foregoing, it is the preliminary judgment of NOVA that the site is
generally geotechnically suitable for infiltration by stormwater BMPs placed within the
constraints cited above; however, the very low infiltration rates suggest a no infiltration condition
at the site. This judgment should be reviewed when the siting of BMPs with respect to proposed
structures, utilities, and other improvements has been finalized by the Civil Engineer.
37
Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
1216, NOVA Project 2020187
NOVA December 7, 2020
E:!s 1.VAl!I I
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.
M.
Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
8
gAA
31 NOVA Project 2020187
N'(-)VA December 7, 2020
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 Traffic Asphalt Base Course
Subgrade R-Value Index Thickness (in) 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).
39
aA Report of Seotechnkal Investigation ik Proposed Portable Classrooms, North County Academy, Carlsbad, California
A NOVA Project 2020187
NOVA 11 December 7, 2020
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 ASIM 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 14-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.
40
Ak
Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
4 NOVA Project 2020187
NOVA December 7. 2020
9.1 Site Specific
North County Academy: Option 1, Alpha Studio Design Group, provided to NOVA October
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 302.1 R-1 5.
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 htto://www.dot.ca.aovlha/esclttsb/corrosion/odf/20 12-11-1 9-Corrosion-Guidelines,Ddf.
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, SP0169-2007.
OSHA Technical Manual, Excavations: Hazard Recognition in Trenching and Shoring, OSHA
Instruction TED 01-00-015, Section V, Chapter 2. Found at:
https:l/www.osha.gov/dts/osta/otm/otm v/ otm v 2.html#1.
OSHPD and SEAOC, Website: Seismic Design Maps, https:/lseismicmaps.orq/.
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 Sub grade Reaction, Geotechnigue, Vol 5, 1955, pp
297-326.
41
Report of Geotechnical Investigation Ør Proposed Portable Classrooms, North County Academy, Carlsbad, California
A NOVA Project 2020187
NOVA December 7, 2020
9.3 Geologic and Site Setting
California Geological Survey (CGS), Information Warehouse: Landslide Inventory:
htts:l/maps.conservation.ca.qov/cqslIsi/, 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, Geoloav 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/siqnificantlindex.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://earthguake.uscis.qov/reqional/gfaults/.
42
g& Report of Gootechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
A31 NOVA Project 2020187
NOVA. December 7, 2020
PLATE
ka
NOVA
A GEOTECHNICAL
SPECIAL INSPECTION
4373 Viewridge Avenue, Suite B
San Diego, CA 92123
P: 858.2927575
944 CaVe Amanecer, Suite F
San Clemente, CA 92673
P: 949.388.7710
www.usa-novacom
Cl)
0
a
>-
WZct
>Z0 F-O
Z<U)
0
I I-
.0 z
-x -.
71
x I x
NORTHCOUNTY ACADEMY SCHOOL 1 x X
- Qop
-
:-
- -
I . B 2
KEY TO SYMBOLS
SHADE Qop OLD PARALIC DEPOSITS
1 AREA 6-4
= GEOTECHNICAL BORING
1 2 PERCOLATION TEST BORING PLAY
AREA SITE LIMITS I LIMITS I 4 CLASSROOMS I OF INVESTIGATION
7
---- 1 1 POTENTIAL AREA FOR WATER
QUALITY MITIGATION
-
MAGNOLIA AVENUE
LOCATION OF IMPROVEMENTS
PROVIDED BY ALPHA STUDIO
DESIGN GROUP. OCTOBER 2020
!ASC0 LARETSIJITER
Sar Jleo 1 Solara lea Orage Court
t'one 858259.8212 ww.saenginevrng.corn lAl
0 30 60
1
PROJECT NO.: 2020187
DATE: DEC 2020
DRAWN BY: DTJ
REVIEWED BY: MS
SCALE: 1"30
DRAWING TITLE:
SUBSURFACE
INVESTIGATION MAP
PLATE NO. 1 OF 1
I WD Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
4 NOVA Project 2020187
NOVA December 7, 2020
APPENDIX A
USE OF THE GEOTECHNICAL REPORT
................................... Geotechnical Engineering Report............ - ----------------
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-
ricer may not fulfill the needs UI a construction contractor or even another
civil engineer. Because each geotechnical engineering study is unique, each
geotechnical engineering report is unique, prepared solely for 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 Report 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
clients goals, objectives, and risk management preferences; the general
nature of the slruclure 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 kir 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
Mat 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 geotechriical engineer-
trig report whose 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 stilt 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 subsurfce 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 grulechnical
engineer who developed your report cannot assume respansibilityor
liability for the report's recommendations if that engineer does not perform
construction obsert'aiion.
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 gee-
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 togs
Geotechnicat engineers prepare final boring and testing togs based upon
their interpretation of field logs and laboratory data. To prevent errors or
omissions, the togs 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 separatinq 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 [by 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 sot e contrac-
tors have sufficient lime 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 ,qeoenviron-
mental study differ significantly From those used to perform a geotechnical
study. For, that reason, a geotechnical engineering report does not usually
relate any geoenvironrrental 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 tiiures. If you have not yet obtained your own qeoen-
vironmental information, ask your geotechnical consultant for risk man
agernent 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 ASFEffhe 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 on larCh
8811 Colesvitte Road/Suite G! 06, Silver Sptirig, MD 20910
Telephone: 301/565-2733 Facsimile: 301/589-2017
e-mail: nfo@asfe.org wee.asfe.org
Copydqht 200$ byAsrr Inc. Duplication, reproduction, or copying of this, document, in whole or in part, 4y any means whatsoever; is strictly prohibited, except with 45FE's
specific written perrntssion. Exceepting, quohnq, or otherwise exlrsclincj wording fi'om this document is permuted only with the express written permission of .4SFtT, 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 qeolechnicat engineering report, Any other
(inn. Individual, or other entity that so uses this docurneni without being an ASFE member could be comm/ring negligent or intentional (fraudulent) misrepresentation.
tIC [RD60$5.0-M
Report of Geotechnical investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
A NOVA Project 2020187
NOVA December 7, 2020
LOGS OF BORINGS
BORING LOG B-i
LAB TEST ABBREVIATIONS
DATE EXCAVATED NOVEMBER 3,2020 EQUIPMENT: CME 75 CR CORROSIVITY MD MAXIMUM DENSITY
DS DIRECT SHEAR
EXCAVATION DESCRIPTION: 84NCHD6,METER AUGER BONG GPS COORO.: N/A El EXPANSION INDEX
SA SIEVE ANALYSIS
RV RESISTANCE VALUE
CONSOLIDATION SE SAND EQUIVALENT
w
Ui0- -J Cl) W
- 8 SOIL DESCRIPTION
SUMMARY OF SUBSURFACE CONDITIONS
I °' 0- 0 (USGS; COLOR, MOISTURE, DENSITY, GRAIN SIZE, OTHER)
a. w w
0
°
GROUNDWATER DEPTH: GROUNDWATER NOT ENCOUNTERED ELEVATION: ±.....62.0 FT ....CN
-J REMARKS
O -
-
-
-
SM
-
- TOPSOIL: SILTY SAND; DARK BROWN, MOIST, LOOSE, FINE TO COARSE GRAINED,
-. SCATTERED GRAVEL, SOME ORGANIC MATERIAL SM OLD PARALIC DEPOSITS (Qop): SILTY SANDSTONE; DARK ORANGE BROWN,
- SLIGHTLY MOIST, MEDIUM DENSE TO DENSE, FINE TO COARSE GRAINED MD X / 21 SCATTERED GRAVEL SA
CR
5 - -
46 ORANGE BROWN WITH GRAY MOTTLING, SLIGHTLY MOIST, DENSE, COARSE SA 9.7% 125.0 pcf
-
GRAINED
SA
19 MEDIUM DENSE SA
10
- i sc - - - CLAYEY SANDSTONE; DAFIK ORANGE BROWN,SLIGHTLY MOIST,MEDIUM DENSE, SA 20 COARSE GRAINED
15 DENSE ( 41
- - - - BORING TERMINATED AT 16.5 FT. NO GROUNDWATER ENCOUNTERED, NO CAVING.
20..
25
30
KEY TO SYMBOLS NORTH COUNTY ACADEMY GEOTFCHCAL
1640 MAGNOLIA AVENUE # ERRONEOUS BWWOOUNT SPECIAL INSPECTMI4 OURS WATES / STAB1LIZEID CARLSRAD, CALIFORNIA
BULN SAMPLE * NO SAMPLE dEOVE1iV APPENDIX B.1 NOVA.
SPTR11P FIASThIS pç' OG~;C CONTACT IE'GCflflV AR DATE DEC 2V20
CAL, MOD. SAMPLE IASTM 035501 - - - SOIL TYPE CHANGE REVIEWED BY: MS PROJECT NO.: 2020i87
BORING LOG B-2
LAB TEST ABBREVIATIONS DATE EXCAVATED; NOVEMBER 3,2020 EOUIPMENT: CME 75 ______ _________________ CR coRosIvrry MD MAXIMUM DENSITY DS DIRECT SHEAR
EXCAVATION DESCRIPTION: 8-INCH DIA E METER AUGER BORING GPS COORO.: NJA EXPANSION INDEX
--
SA SIEVE ANALYSIS RV RESISTANCE VALUE
CONSOLIDATION SE SAND EQUIVALENT
Ui
Lu w cc SOIL DESCRIPTION
-
GROUNDWATER DEPTH; GROUNDWATER NOT E4COUNTEREDELEVATION: * FT .MSL..CN
SUMMARY OF SUBSURFACE CONDITIONS
S 0 (USCS; COLOR, MOISTURE, DENSITY, GRAIN SIZE, OTHER) ir
cc
0 0 (/)? m °- REMARKS
0 - - SM -
-
-
TOPSOIL: SILTY SAND; DARK BROWN, MOIST, LOOSE, FINE TO COARSE GRAINED,
SM SCATTERED GRAVEL, SOME ORGANIC MATERIAL
FILL (Mu): SILTY SAND; DARK ORANGE BROWN, MOIST, MEDIUM DENSE, FINE TO MD
MEDIUM GRAINED I VERY LOW V
A
.
SC 32 OLD PARALIC DEPOSITS (Clop): CLAYEY SANDSTONE; DARK ORANGE BROWN, RV 10.4% 123.6pc1
V MOIST, MEDIUM DENSE, FINE TO MEDIUM GRAINED
5 ........
/ 27 FINE GRAINED
55 ILB% 127.9pc1
10
- I sp-sc - - 26 POORLY GRADED SANDSTONE WITh CLAY; DARK ORANGE BROWN WITH GRAY
MOTTLING, MOIST, MEDIUM DENSE, MEDIUM GRAINED
SM SILTY SANDSTONE; DARK ORANGE BROWN, MOIST, DENSE FINE TO COARSE
GRAINED
15
/ 48
20 WET, FINE TO MEDIUM GRAINED - / 39
- - - - BORING TERMINATED AT 21.5 FT. NO GROUNDWATER ENCOUNTERED. NO CAVING.
J
25—
H 30
KEY TO SYMBOLS NORTH COUNTY ACADEMY
540 MAGNOLIA AVENUE AITERfALS
000UNOWATER! STABILIZED # ERRONEOUS BLOWDOUNT SPECIAL WSPECMI4
CARLSBAD, CALIFORNIA
RI) " AVPL E * U SAMPLE RECOVERY APPENDIX B.2 NOVA 'vs
S"T RAMP F ARTh4 'i ______ "ED ('5Cr' CONTACT LOGGED rfl flV AR DATE DEC. W20
('Al 100 AMLE A - - - I TYPE "HA"F REV5EBED BY MS PPOJflTNO 02) 87
BORING LOG B-3
LAB TEST ABBREVIATIONS DATE EXCAVATED: NOVEMBER 3,2020 EQUIPMENT: CME 75 __________ ______________ CR CORROSIVITY MD MAXIMUM DENSITY DS DIRECT SHEAR
EXCAVATION DESCRIPTION: 8-INCH DIAMETER AUGER BORING GPS COORD.: N/A El EXPANSION INDEX AL ATrERBERGuWTS SA SIEVE ANALYSIS
RV RESISTANCE VALUE
... ....183.pFT ....CN GROUNDWATER DEPTH: GROUNDWATER NOT ENCOUNTERED ELEVATION: ........ CONSOLIDATION SE SAND EQUIVALENT
Ui
Lu
-J (1) Ui >.
8 a- cnC6 SOIL DESCRIPTION
- z SUMMARY OF SUBSURFACE CONDITIONS
I - 0 (USCS; COLOR, MOISTURE, DENSITY, GRAIN SIZE, OTHER)
O 2. - REMARKS
O flr - - SM - TOPSOIL: SILTY SAND; DARK BROWN, MOIST, LOOSE, FINE TO COARSE GRAINED,
-
- SCATTERED GRAVEL, SOME ORGANIC MATERIAL
OLD PARALIC DEPOSITS (Qop): SILTY SANDSTONE WITH CLAY; DARK ORANGE SM
BROWN TO BRO WN,MOIST. MEDIUM DENSE -
/ 21 SA
FINE GRAINED
iiii
-----------------
55
-------------------------------
SILTY SANOSTONEJSANDYSILTSTONE; DARK ORANGE BROWN TO BROWN, MOIST. SA 11.3,y. 126,lpcf
x
VERY DENSE
— — —
SM
— — - — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —
SILTY SANDSTONE WITH CLAY; ORANGE BROWN WITH GRAY MOTTLING, SLIGHTLY
- — — — — — — — — — — — — —
/ 23 MOIST, MEDIUM DENSE, FINE TO MEDIUM GRAINED SA
10 ORANGE BROWN WITH GRAY MOTTLING, MEDIUM DENSE
/ 18 SA
DARK ORANGE BROWN, MOIST, DENSE, MEDIUM GRAINED DRILLING BECOMES MORE DIFFICULT
15 DARK ORANGE BROWN TO GRAY BROWN, MOIST, DENSE SA - -
X
42
20
DARK ORANGE BROWN WITH GRAY MOTTLING, VERY MOIST TO WET SA
/ 51
- - - - BORING TERMINATED AT215 FT NO GROUNDWATER ENCOUNTERED. NO CAVING.
25
30
KEY TO SYMBOLS NORTH COUNTY ACADEMY 4A GOTECHCAL.
1640 MAGNOLIA AVENUE IAI MATLS
I'P' PC)ATFS TBIL YE" # E'WEOUS0LOVCE'
(AR SEAC CALIFORNIA
SULK SAMPLE * NO SAMPLE AECOVEHY NO\TA.
Z SPT SAMPLE F AM04:586)______ GEOLOGIC CONTACT LOGGED flY AR DATE DEC 020
.APPEUDXB3
CAL. MOD. SAMPLE LASIM 035501 - - - SOIL TYPE CHANGE REVLEWED BY: MS PROJECT NO.: 202087 7W
BORING LOG B-4
LAB TEST ABBREVIATIONS
DATE EXCAVATED: NOVEMBER 3,2020 EQUIPMENT: CME 75 __________________ CR CORROSIVITY MD MAXIMUM DENSITY OS DIRECT SHEAR
EXCAVATION DESCRIPTION: 8-INCH DIAMETER AUGER BORING GPS COORD.: N/A El EXPANSION INDEX
SA SIEVE ANALYSIS RV RESISTANCE VALUE GROUNDWATER DEPTH: GROUNDWATER NOT ENCOUNTERED ELEVATION: ±....1.6.1.0-FT ..MSL CONSOLIDATION
SE SAND EQUIVALENT
w -J CC
.CN
W SOIL DESCRIPTION
LL -J z SUMMARY OF SUBSURFACE CONDITIONS
co (USGS; COLOR, MOISTURE, DENSITY, GRAIN SIZE, OTHER) a. < W
...0 —ø 0 or .JW
0
a: < ° " w°- - REMARKS
O - SM - TOPSOIL: SILTY SAND; DARK BROWN, MOIST, LOOSE, FINE TO COARSE GRAINED,
- - - -... SCATTERED GRAVEL, SOME ORGANIC MATERIAL SC OLD PARALIC DEPOSITS (Oop): CIA VEY SANDSTONE; DARK ORANGE BROWN, -
SLIGHTLY MOIST, MEDIUM DENSE, FINE GRAINED
28 9.6% 119.5pc1
5 ........
23 ORANGE BROWN
SM SILTY SANDSTONE WITH CLAY; ORANGE BROWN, MOIST, MEDIUM DENSE, MEDIUM -
/
24 GRAINED
10
/ 24
15 ORANGE BROWN WITH GRA Y-BROWN MOTTLING, VERY MOIST TO WE DENSE ( 31
20- -
/ 32 WET
- - - - BORING TERMINATED AT 21,5 FT. NO GROUNDWATER ENCOUNTERED. NO CAVING,
25........
KEY TO SYMBOLS NORTH COUNTY ACADEMY GEOTECHC4L
640 MAGN QUA AVENUE ATERIALS
11h, GROUNID WATER? STABILiZED # ERRONEOUS SLOWCOUNT SPECIAL NSPECTMN
CARLSBAD. CALIFORNIA
BULN SAMPLE * NO SAMPLE RECOVERY - APPENDIX B.4 NOVA
RPTSAMP FIAM' E€ F(' OCICO'TArT DECI020 000001W
]~~E
CAL. MOLD. SAMPLE LASTM 035501 - - - SOIL TYPE CHANCE REVIEWED BY: MS PROJECT NO:: 2020i87
.
PERCOLATION BORING LOG P-i
LAB TEST ABBREVIATIONS DATE EXCAVATED: NOVEMBER 3,2020 EQUIPMENT: CME 75 _____________ CR CORROSIVITY MD MAXIMUM DENSITY DS DIRECT SHEAR
EXCAVATION DESCRIPTION: 8-INCH DIAMETER AUGER BORING COORD.: NJA El EXPANSION INDEX AL ArrERBERGUMErS SA SIEVE ANALYSIS RV RESISTANCE VALUE
CONSOLIDATION SE SAND EQUIVALENT
w
Cl) w >.
a. <
GROUNDWATER DEPTH; GROUNDWATER .NOT ENCOUNTERED ELEVATION: ±........ ..............................................................................CN
SOIL DESCRIPTION
- SUMMARY OF SUBSURFACE CONDITIONS
1 0 & (USCS; COLOR, MOISTURE, DENSITY, GRAIN SIZE, OTHER) a. a. < w —i--i 0 Cl) O _iLLJ 0 cc 0
< ° C"- - REMARKS
0 SM — TOPSOIL; SILTY SAND; DARK ORANGE BROWN, MOIST. LOOSE, FINE TO COARSE
- - - GRAINED, SCATTERED GRAVEL SC OLD PARALIC DEPOSITS (Qop): CLAYEY SANDSTONE ORANGE BROWN. SLIGHTLY
MOIST, MEDIUM DENSE, FINE GRAINED
BORING TERMINATED AT5 FTAND CONVERTED TOA PERCOLATION WELL.
10........
15........
20--
26-
30
KEY TO SYMBOLS NORTH COUNTY ACADEMY A GEOTECHL
1640 MAGNOUA AVENUE ATERIALS
All GROUWATEPJ $TAE1LIZED # ER 13 SPECIALINSPErMN
CARLSBAD. CALIFORNIA
E1fl..K SAMPLE * NO SAMPLE COVERY APPENDIX 8.5 NOVA
9PTAHP FAR' CF' CCCCTAC OSCDI3Y AR DATE DEC 2,020
CAL. MOD. SAMPLE AST — — — SOIL TYPE CHANGE REVEWED BY: MS PROJECT NO.: 37 ................ 67
PERCOLATION BORING LOG P-2
LAB TEST ABBREVIATIONS
DATE EXCAVATED: NOVEMBER 3,2020 EQUIPMENT: CME 75 __________ _________ CR CORROSIVITY MD MAXIMUM DENSITY
CS DIRECT SHEAR
EXCAVATION DESCRIPTION: 8-INCH DIAMETER AUGER BORING GPS COORO.: N/A El EXPANSION INDEX
SA SIEVE ANALYSIS
RV RESISTANCE VALUE
GROUNDWATER DEPTH: GROUNDWATER NOT ENCOUNTEREDELEVATION: ±....63.0 FT CONSOLIDATION
SE SAND EQUIVALENT
w —J Cl) w
0 SOIL DESCRIPTION
-
In SUMMARY OF SUBSURFACE CONDITIONS
I (/) 0 U) (USGS; COLOR, MOISTURE, DENSITY, GRAIN SIZE, OTHER) ir I— < W 0 .JW —co ca 0
cr ° (3 < Q
,j CI) &
.CN
REMARKS
0 -
-
-
-
SM
-
- TOPSOIL: SILTY SAND; DARK ORANGE BROWN. MOIST, LOOSE, FINE TO COARSE
-.. GRAINED
SC OLD PARALIC DEPOSIT (Qop): CLAYEY SANDSTONE; DARK ORANGE BROWN,
SLIGHTLY MOIST, MEDIUM DENSE, FINE TO COARSE GRAINED
BORING TERMINA TED A T 5 FT AND CONVERTED TO PERCOLATION WELL.
10........
15 ........
20 ........
25--
30
KEY TO SYMBOLS NORTH COUNTY ACADEMY AOTECHNICAL
1640 MAGNOLIA AVENUE MThRLS
411 GROUNDWATER / $TABIUZED # ERRONEOUS BLOWCOCJNT SPECIAL INSPECM14
CARLSBAD. CALIFORNIA
BULK SAMPLE * NO SAMPLE RECOVERY APPENDIX NOVA.
OPT SAMPLE (A'TM '' JEt,) GEOLOGIC CONTACT CV AR DATE DEC 2020
4373 V'/dg Ae 34 13
"
CAL. MOD. SAMPLE IASTM 83550j - - SOIL TYPE CHANCE REVIEWED BY: MS PROJECT NO.: 2020187 ,C4 73673
Report of Geotechnical Investigation Al Proposed Portable Classrooms, North County Academy, Carlsbad, California
Mkk NOVA Project 2020187
NOVA.
-- December 7, 2020
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:
. 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 01557 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 01557, 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 04829): The expansion index of selected materials was evaluated in general accordance with ASTM 04829. Specimens
were molded under a specified compaclive 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 0 2844. Samples were prepared and evaluated for exudation pressure and expansion pressure. The equilibrium Fl-value is reported as
the lesser or more conservative of the two calculated results.
. GRADATION ANALYSIS (ASTM C 136 and/or ASTM 0422): Tests were performed on selected representative soil samples in general accordance with
ASTM 0422. The grain size distributions of selected samples were determined in accordance with ASTM C 136 andirir ASTM 0422. The results of the
tests are summarized on Appendix C.3 through Appendix C. 13.
GEOiECHNCAL LAB TEST SUMMARY 4A MATERIALS
A'
SPECIAL INSPECTION NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE 1\TO\TI vø,Br * scvoso •SLOC. CARLS8AD, CALIFORNIA
i3 r44 'A V Svi Qh - CA BY CLS .)AE DEC 200 PRC)JI-( 12020187 APPENDIX-. CA
Maximum Dry Density and Optimum Moisture Content (ASTM D1557)
Sample Maximum Optimum Moisture
Sample Depth Dry Density Content
Location (ft.) Soil Description (pcf) (%)
B- 1 2 - 5 Dark Orange Brown Silty Sandstone 135.1 8.1
B- 2 1 - 5 Dark Orange Brown Clayey Sandstone 132.5 7.9
Density of Soil in Place (ASTM D2937)
Sample
Sample Depth Moisture Dry Density
Location (ft.) Soil Description
B-I 5 Orange Brown Silty Sandstone 9.7 125.0
B-2 2.5 Dark Orange Brown Clayey Sandstone 10.4 123.6
B-2 7.5 Dark Orange Brown Clayey Sandstone 11.8 127.9
B-3 5 Dark Orange Brown Silty Sandstone 11.3 126.1
B-4 2.5 Dark Orange Brown Clayey Sandstone 9.6 119.5
Expansion Index (ASTM D4829)
Sample Sample Depth Expansion Expansion
Location (ft.) Index Potential
B-2 1-5 1 Very Low
Resistance Value (Cal. Test Method 301 & ASTM D2844)
Sample
Location
Sample
Depth
(ft.) Soil Description R-Value
B-2 1 - 5 Dark Orange Brown Clayey Sandstone 38
Corrosivity (Cal. Test Method 417,422,643)
Sample Sample Depth Resistivity Sulfate Content Chloride Content
Location (ft.) pH (Ohm-cm) (ppm) (%) (ppm) (%)
B-1 2 - 5 8.6 3300 39 0.004 32 0.003
OR
GEOTECHNtCAL
MATE*ALS
SPECIAL INSPECTION
LAB TEST RESULTS
NORTH COUNTY ACADEMY
1640 MASNOLAAVNUE
TO NOVA , • • CARLSBAD, CALIFORNIA
4 Ci A *
iCIA 92TV"BY CLS DATE DEC 2020 PROJECT: 2020187 APPENDIX C,2
E— Size (Jnhee) ( US Standard stave Sizes > ( Hydrometer Analysis
Gravel Sand Silt or Clay
Coarse Fine Coarse Medium Fine
Sample Location: B-i
Depth (II): 2-5
USCS Soil Type: SM
Passing No. 200 (%): 35
A GEOTECHNICAL
MATERIALS
Jim SPECIAL INSPECTION
TO\TA OVEIZ . ISBE , 6DVOSl3 I SLOE
v44C:-i --
1 1
GRADATION ANALYSIS TEST RESULTS
NORTH COUNTY ACADEMY
1640 MAGNOLA AVENUE
CARLSBAD, CALIFORNIA
BY: CLS DATE: DEC 2020 PROJECT: 2020187 APPENDIX: C3
4 Size (iflthG) > U.S. Standard Sieve Sizes ( Hydrometer Analysis
UI
100
- *
90 --—:--
I I
I II \ I
I I
80 —ii ------ -. - * *
70
to
-.-- -1 •r -1- -
I I I* I
60 -
! 'l
U II I I
: IF I I .1: I $ I :1
* *1 I I $ I I
40
.- *
I II I I I I I
I I ii I I I I I I
30 II II I I I
I I II I l I 4 I
it
I II I I I I I I
I4 I I I 1
20 1* t t $ 1 I
Itl i Ii I I 4 I II I I l I I I * 1
10 --..---.-it
*4 I I I I * 1
I II III I I I Ii
I II II I I I II
0' . i.
100 10 1 0.1 0.01 0.001
Grain Size (mm)
Sample Location: B-i
Depth (It): 5'
USCS Soil Type: SM
Passing No. 200 (%): 47
T
11 -
GEOTECHNICAL GRADATION ANALYSIS TEST RESULTS
MATERIALS
1A SPECIALINSPECTION NORTH COUNTY ACADEMY
aks. 1840 MAGNOLiA AVENUE NOVA • CARLSBAD, CAUFORNIA
HGee.I. S N N44 O? IIv: iN:N, r
C]II,wnt't, CA BY: CLS DAlE: DEC 2020 PROJECT: 2020187 APPENDIX: C4
Gravel Sand
Silt or Clay
Coarse Fine Coarse Medium Fine
4— Size (Inches) —* ( U.S. Standard Sieve Sizes > ( Hydrometer Anaysis
S
qu
80.0
100,0 ................
--.-
j
66 i 9
I II
iJ :
I
II II' --1-4
1 6 6 z
'I
1170.0
600
I II I1
* *
I- II
I
I
I
I 50.0
1 II I.Ii :1 I .,II
400 :
I I II Ii * I I
II I.I I I
300 I,
I
I
II II
I II III
I
II
I I
I
, .. .
I I II .11 $
I I II II
20.0 ..............................
I 100
I II I I I
I I. II I 1
I
I
I II III
II I$
I
I I I
0.0_.L.____ I..iJJ_sLJL.. ..........L _i_i_t_.
100 10 1 01 0.01 0.001
Grain Size (mm)
Gravel Sand Silt or Clay
Coarse Fine Coarse Medium Fine
Sample Location: 8-1
Depth (It): 7-10
USCS Soil Type: SM
Passing No. 200 (%): 44
A MATERIALS At SPECIAL INSPECTION
NOVA
A.'5rrN. 1 i44 C
GRADATION ANALYSIS TEST RESULTS
NORTH COUNTY ACADEMY
1840 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
BY: CLS I DATE: DEC 2020 I PROJECT: 2020187 I APPENDIX: C.5
4— size (Iswhrs) —>E----------- U.S. Sitandard Sieve sizes > ( Hydrometer Analysis
¶ 100 *3_4T j4r r
I I l\1 I I
I I I I I
90 T, -L-LiL I L ji j I
I I $ I\ * * 4
I I I I *\ I I II
I I II I * I
I 1:1 I I
80
I I It II I I
I I $ II I I II
70 rri i r *
* I * I
to I * *
60 .
C * 4 I4
I 1* I
el 50 * 4 ..............
I I, II II I I I
I I It Ii I 40 ................................... I 1 S 5
S 4 4 *1 II I I
30
I II I I
I I I II I I\ I
I I I I 1 I I I
*1 II II I I I
20 * S .. 4** l4
Ii I 14 4.4 I I I
1 41 II II Ij I I I
S II . 11 II II I 4 I I 10 I... S
'I I II 44 II 4 I
o
100 10 1 0.1 0.01 0.001
Grain Size (mm)
Sample Location: B-i
Depth (ft): 7.5•
USCS Soil Type; SM
Passing No. 200 (%>: 29
A GOTECI4W4CAL GRADATION ANALYSIS TEST RESULTS tA' MATERIALS
SPECIAL INSPECTION NORTH COUNTY ACADEMY
1640 MAGNOLiA AVENUE N5O\T1 evsc eec • eevoee SLCE CARLSBAD, CAUFORNIA
nv,,usa5nvlItor
4:I?e Cii CCl'li. SiC C Cii:C Ai•Ci, 1CiiC C BY: GLS DATE: DEC 2020 PROJECT: 2020187 APPENDIX: CM
P: 2C.'C7C
Gravel Sand Silt or Clay
Coarse Fine Coarse Medium Fine
E— Size (IncheaJ —>< U.S. Standard Sieve Saes > ( Hydrometer Analysis
co
ioo. ¶r1 r'1
90 Hf' 4- -
so
is
70 -.---.-,
I •l * I* *
CL
I I
* I * II
60
c *: * :*I : :
. . . i•4i; .f...... ..* . }Lj.
II I I I I I
I II I 4 4 I 4
k is
I I II * I I
is
I 4 4 I 1
I 4 -. t
Ti
I I II I I * * I
ut * \* *
I *4 I * I • I
30 I If L. 1: 8j l\ L
I II I $ I 4 I
I I *4 4 1 4 I I
II I I
20 1 t$ 4 4 If *1 *4 I 1 1 4 I 4
I * 4 I II I 4 I I I I 1 4 I 1
4 II *I 1 r I II III 4 I *f
I Ii II I I I
I II I 4 I
100 10 1 0.1 0.01 0.001
Grain Size (mm)
Sample Location B- 1
Depth (ft): 10'
USCS Soil Type; Sc
Passing No. 200 (%); 26
AA GE0TEC4*CAL GRADATION ANALYSIS TEST RESULTS
At,
MATERIALS
SPECIAL IN5PEC11O4 NORTH COUNTY ACADEMY
1840 MAGNOLIA AVENUE. N O\T& ovac • sa • evoaa • CARLSBAD, CALIFORNIA
4L Sr S l44 Ca:S Sre 3!1 BY; CLS DATE: DEC 2020 PROJECT: 2020187 APPENDIX: 0.7
Gravel Sand Silt or Clay
Coarse Fine Coarse Medium Fine
4— SIze (Thchez) < U.S. Standard Sieve sizes > ( Hydrometer Analysis
100.0
90.0
80.0
70.0
U)
(5
60.0
w U
50.0
40.0
30.0
20.0
10.0
8 8 8
S ,• 1,.
I I II .1 I I I I
I I II 1 \I I
I I II
I II
1
1
II
l
I
I
1 .4. ..........
II
4..
1
4.5.... .5..4........ ,4 . S...... - -
II St I• 1*
I II
II ) I
I II 'I t\t
I II 1 t* I I
.? .lj......._
I I)
ii.
1 I I t
I It t I\ I I
t t * 1 I I
• I
I
I I
1
I
I
I
I
I
t'..•
I
P
*
I
II
I II
I*
PI1I: I
II
I P
S
I.... ,,I•, .1* JI ,t I. I. I
I I II II II
I 1 II II 1
I I II tt $
• I I It II II I
• 1tt I II S. S
I I $1 I*• I I I II
I I I) It I I I 1
I I II I,I I I I 1
I II II I I I I
t
I 1 It II II I I
0.0 ij.LI.L
100 10 1 0.1 0.01 0,001
Grain Size (mm)
Gravel Sand
Silt or Clay
Coarse Fine Coarse Medium Fine
Sample Location: B- 3
Depth (It): 2.5
USCS Soil-Type: SM
Passing No. 200 (%): 40
A GCOTECHNICAL
MATERIALS
Ake
SPECIAL INSPECTION
O'\TA. OVIK • • S VOTE ELSE
4"K13 Vu4rki9r A4ri3r, Siir Ii cliiir. V,-w, 154V
rcCAti2S7it
GRADATION ANALYSIS TEST RESULTS
NORTH COUNTY ACADEMY
1648 MAGNOUA AVENUE
CARLSSEAD, CAUFORNIA
By: CLS DATE: DEC 2820 PROJECT: 2820187 APPENDIX: C.8
* Size (kches) > < U.S. Standard Sieve Sizes > Hydrometer Analysis
100 1-4 •4—IO 1 lJ —rr * — —
I I
I I I
90 —
I 4 I•
80
4.
I I 1 4
I I I I $ 70 -*...--— I iI
51 \
60 i: -r- I II I 4 4 4 I II II II I I I
11 I I I I $ I 50 k i * *
4 4 II I 4 4 4 4
I I II I I I I I 1
4 I 44 I I $ I I 4
LI I II I I I I I I 9V 4 I 4 4 4
I I II I I I I * 4
I I II I I I I I 4
I I $4 I 4 I I I 4
30 4 ii & I I I
* I II I I I 4 I I
I I II II I I I 4
I II I I I I I
I I II I I I I 20 t
I III4 II II I
I I 14 II III I
I II I I I I I 'I
10 II 'I I I11 I I if
I II I I I I I II I I 4 I I I I
1 I II II I I I
0-
100 10 1 0.1 0,01 0.001
Grain Size (mm)
Sample Location: B- 3
Depth (ft): 5
USCS Soil Type: SMJML
Passing No. 200 (%): 55
'A GEOTECHNICAL GRADATION ANALYSIS TEST RESULTS
A'
MATERIALS
SPECIAL I*4SPECI1ON NORTH COUNTY ACADEMY
'1 TQ T A 1640 MAGNOLIA AVENUE
IN V A. - • • svosa * snz CARLSBAD, CALiFORNIA
41 fl.'lyz A'sz*. Szz H 44 CH 4*. F BY: CLS DATE: DEC 2020 PROJECT: 2020187 APPENDIX: 0.9
Gravel Sand Silt or Clay
Coarse Fine Coarse Medium Fine
E Size (inches) > < U.S. Stardard Sieve Sizes > < HydiromeW Ana1ySi
100 1 • —'Se— - 1 - - .- - - * *
it
ll
70
I :
it L
it
l
:
L\
50 CL
it I
40 I I I I I t \I I
I I I Ok
30
I 1
3 I
8 3
I I
I I
3 8,4 &
I
I I I II 3
I I I I I I
I I I * I I
20 I 1 I I I I I
I' 4
I
I I I I I I I I
1 I 3 3 I
10
I
*
I
I
I
I
$ I
I $
I I I I
I I I
I
I 1 1 I 11 1 I 1 1 1
I I 13 $ I I I I I
I I 113 & 3 I
8 I U *11 I 4 I I
0L !_L_Lii_ _L . L..L_i
100 10 1 0.1 0,01 0,001
Grain Size (mm)
Gravel Sand Silt or Clay
Coarse Fine Coarse Medium Fine
Sample Location: B 3
Depth (ft): 7.5'
USCS Soil Type: SM
Passing No. 200 (%): 31
A GEOTECHNICAL
At MATERIALS
SPECIAL I&ISPECT$ON
Nk")VA WEE • • svon
15$ 144 C1 I
San CA
Pr13I1.T7
GRADATION ANALYSIS TEST RESULTS
NORTH COUNTY ACADEMY
1640 MAGNOLA AVENUE
CARLSEAD, CAUFORNiA
BY: CLS DATE: DEC 2020 PROJECT: 2020187 APPENDIX: 0.10
*— size (1rrCh) >< U.S. Standard Stave Sizes > ( Hydrometer Analysis
g S q C) W) - C'4
Grain Size (mm)
Gravel Sand Silt or Clay
Coarse Fine Coarse Medium Fine
Sample Location: R 3
Depth (ft): 10
USCS Soil Type; SM
Passing No. 200 (%): 25
jA MATERIALS
SPECIAL INSPECTION
N(Ij\T.,\. owns • nes • sovons
EOt
Aee. C 44CI Cta
Sdr QA12:
GRADATION ANALYSIS TEST RESULTS
NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
BY: CLS DATE: DEC 2020 1 PROJECT: 2020187 APPENDIX: CI1
*— Se (inches) ->E-------- U.S, Standard Sieve sizes > ( HyromGtcr Analysis
100 t -
e.t--.-o WIN rTrr $ TIT ,$. $
90 I I •I - I
I I 1
I I 1
80 * ".
iI I
I lI I
70 ." * . ,,. ,
to
60
C * II I I ii
I l I I I\I I I
I I l I I I I
501 if 1+ I I I * 4
I * I I I I I
I II I I I I I
1*
I I ii I I I I\ I 13
401 1 I I I *1
if 11 1
i: H ki L :L C 10 I
100 10 1 0.1 0.01 0.001
Grain Size (mm)
Sample Location: B - 3
Depth (II): 15'
USCS Soil Type: SM
Passing No. 200 (%): 22
A GeoTsc*N*cAL GRADATION ANALYSIS TEST RESULTS
MATERIALS
SPecIAL
INSPECTION NORTH COUNTY ACADEMY
1640 MAGNOLIA AVENUE N OVA CARLSBAD, CALIFORNIA
4:373 37 '384y3 A33e. 33.-13' n 34373 7$
3338 373334, 0A32371- BY: CLS DATE: DEC 2020 PROJECT: 2020187 APPENDIX: 0.12 Pa233.7573
Gravel Sand Silt or Clay
Coarse Fine Coarse Medium Fine
Grain Size (mm)
Gravel Sand Silt or Clay
Coarse Fine Coarse Medium Fine
Sample Location: B-3
Depth (if): 20'
USCS Soil Type: SM
Passing No. 200 (%): 15
1A
MMMAALS
SPECIAL INSPECTION
NOVA 00V053
4323 N5I A133 S1I N 344 CN3 Ar3H, 34N
r.g.CA$3$23
GRADATION ANALYSIS TEST RESULTS
NORTH COUNTY ACADEMY
1640 MACiNOLA AVENUE
CARLSBAD, CALIFORNIA
BY: CLS DATE: DEC 2020 PROJECT: 2020187 APPENDIX: C13
Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California mil NOVA Project 2020187
NOVA December 7, 2020
APPENDIX D
INFILTRATION FEASIBILITY
DOCUMENTS
Appendix I: Forms and Checklists
Piri I - Full Infiltration Fea,~ihflio, ScrceninLZ Criteria
\Vould infiltration of the full deign olume be feasible from a physical l)Crl)cCti\ c without mv undesirable
C011Sil1ieflC1 IIt:it cannot he rcasonabl mittLdtcd?
Cri teria coltc' l)it, Yes No
Is the estimated reliable infiltration rate below proposed
facility locations greater than 0.5 inches per hour? "i'he response
1 to this Screening Question shall be based on a comprehensive X evaluation of the factors presented in Appendix C,2 and Appendix
D.
Provide basis:
The infiltration rate of the existing soils for locations P-i and P-2, based on the planning
phase on-site infiltration study was calculated to be less than 0.5 inches per hour ( P-I =
0.02 and P-2=0,03 inches per hour) after applying a factor of safety (FS) of FS=2.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
Can infiltration greater than 0.5 inches per hour be allowed
without increasing risk of geotechnical hazards (slope stability,
2 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:
No. See Criterion 1.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
1-3 February 2016
Appendix I: Forms and Checklists
H
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.
Provide basis:
Water contamination was not evaluated by NOVA Services.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
chscussicn of study/data source applicability.
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.
Provide basis:
The potential for water balance was not evaluated by NOVA Services.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
If all answers to rows I - 4 are "Yes" a full infiltration design is potentially feasible.
P Part The feasibility screening category is Full Infiltration
Proceed to Result If any answer from row 1-4 is "No", infiltration may be possible to some extent but Part 2
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 M.S4 Permit. Additional resting and/or studies may be required by the City to substantiate Findings.
1-4 February 2016
Appendix I: Forms and Checklists
\ould infiltration of water in :iriv appreciable amount bt. ph'icallv fe.iihle without cLlv neati\ c
cnscqernr that cannot he rea nably niinatcd
n'iIJ 'ia:h tiin \e No
Do soil and geologic conditions allow for infiltration in any
5 appreciable rate or volume? The fCSOflSC to this Screening
Question shall be based on a comprehensive evaluation of the
factors presented in Appendix C.2 and Appendix D.
Provide basis:
The infiltration rate of the existing soils for locations P-i and P-2, based on the planning
phase on-site infiltration study was calculated to be P-i = 0.02 and P-2=0.03 inches per
hour, after applying a factor of safety (FS) of FS=2.
Infiltration rates of less than 0.5 inches per hour and greater than 0.01 per hour imply that
geologic conditions allow for partial infiltration.
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.
Can Infiltration in any appreciable quantity be allowed
without increasing risk of geotechnical hazards (slope
6 stability, groundwater mounding, utilities, or other factors) X 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.
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 hydrocoHapse, 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.
1-5 February 2016
Appendix I: Forms and Checklists
=1- . . ..... IMMUK F
f. C
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 (:.3.
Provide basis:
Water contamination was not evaluated by NOVA Services.
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.
Can infiltration be allowed without violating downstream
8 water rights? The response to this Screening Question shall be
based e:m a comprehensive evaluation of the factors presented in
Appendix C.3.
Provide basis:
The potential for water balance was not evaluated by NOVA Services.
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.
If all answers from row 58 are yes then partial infiltration design is potentially feasible.
Part 2 The feasibility screening categl:ry, is Partial Infiltration.
Partial Result* If any answer from row 58 is no, then infiltration of any volume is considered to be Infiltration
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.
1-6 February 2016
Report of Geotechnical Investigation
Proposed Portable Classrooms, North County Academy, Carlsbad, California
A . NOVA Project 2020187
NOVA. December 7, 2020
APPENDIX E
GUIDE SPECIFICATIONS FOR
21.
NOVA Guide Specifications for Earthwork
[c1.1i#ii
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
01,
NOVA Guide Specifications for Earthwork
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,
2
21
NOVA. Guide Specifications for Earthwork
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.
XqiWi1I]
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.
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.
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.
Oka
NOVA Guide Specifications for Earthwork
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., El > 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).
4
NOVA Guide Specifications for Earthwork
OR,
fGVNAL,
MIN
- -r. - , . . t. J .N
TOPSOIL, CO. JIU ( I..AVA4P-
A _
AI'40 REGRADE ND
- BEDROCK UNWEATHERED BEDROCK
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.
Backfi!Iing
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.
5
NOVA Guide Specifications for Earthwork
LI I [.11[.) J'i 1 :11 liii a
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 11/2 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.
A
m
li
NOVA Guide Specifications for Earthwork
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.
SURFACF OF F RM
EARTH MATE'AL
FILL SLOPE \
5* MIN
16'URN, (INCLINED 2% MIN, INTO SLOPE)
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.
7
Ski,
NOVA Guide Specifications for Earthwork
IFIUIh'it.
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.
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.
'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.
01,
NOVA Guide Specifications for Earthwork
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 01557 (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.
NOVA Guide Specifications for Earthwork
Compaction Testing
Genera!
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 poridiag 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.).
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.
iN
NOVA Guide Specifications for Earthwork
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.
II [i1.. I [I) I-MINTIMUZ01MI [e
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.
11
Al,
NOVA Guide Specifications for Earthwork
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.
12