HomeMy WebLinkAbout3190; Rancho Santa Fe Road Alignment Soils; Rancho Santa Fe Road Alignment Soils; 1990-07-01ADDENDUM TO SOIL AND
GEOLOGIC INVESTIGATION
FOR
RANCHO SANTA FE ROAD ALIGNMENT
CARLSBAD, CALIFORNLA
PREPARED FOR
THE FIELDSTONE COMPANY
SAN DIEGO, CALIFORNIA
PREPARED BY
GEOCON INCORPORATED
SAN DIEGO, CALIFORNLA
JULY 1990
4
0
GEOCON
INCORPORATED
Geotechnical Engineers and
Engineering Geologists
File No. 04367-04-02
July 10, 1990
The Fieldstone Company
5465 Morehouse Drive, Suite 250
San Diego, Califomia 92121
Attention: Mr. John Barone
Subject: RANCHO SANTA FE ROAD ALIGNMENT
CARLSBAD, CALIFORNIA
ADDENDUM TO SOIL AND GEOLOGIC INVESTIGATION
References: 1) Supplemental Soil and Geologic Investigation for Rancho
Santa Fe Road Alignment; Carlsbad, Califomia, pre-
pared by Geocon Incorporated, dated January 8,1990.
2) Rancho Santa Fe Road Conceptual Mass Grading
Exhibit, 1 inch equals 200 feet, prepared by Project
Design Consultants, revised date June 22, 1990.
Gentlemen:
In accordance with your request, this addendum letter updates the referenced soil and
geologic report by submitting herein our revised grading specifications. We have also
reviewed the referenced grading plan to delineate subdrain locations within the proposed
fill areas.
The recommendations presented in the revised grading specifications supersede those
recommendations previously presented in the grading specifications ofthe referenced report.
Prior to utilizing the updated grading specifications for bidding purposes, it is recommended
that the specifications be reviewed and approved by the City of Carlsbad Engineering
Department.
The referenced grading plan modified to include the proposed locations of the subdrains is
attached as Figure 1. The locations and lengths ofthe subdrains presented are approximate
and may be revised during grading as appropriate. The construction of the subdrains should
be performed in accordance with Figure 3 of the referenced report with the following
modification: The option to substitute Class H permeable material for open-graded
aggregate should be deleted from the subdrain detail due to extended subdrain lengths.
6960 Flanders Drive
San Diego, CA 92121-2974
619 558-6900
FAX 619 558-6159
File No. 04367-04-02
July 10, 1990
We appreciate the opportunity to be of continued service. Should you have questions
regarding this addendum letter, please contact the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
^ Monte L. Murbach
RCE 22527 L Project Geologist
MLM:DFL:slc
enclosure(s)
(2) addressee
(6) Project Design Consultants
Attention: Mr. Brad Smith
(1) Fieldstone/La Costa Associates
Attention: Mr. Doug Avis
RECOMMENDED GRADING SPECIFICATIONS
1 GENERAL
1.1 These Recommended Grading Specifications shaU be used in conjunction with the
Geotechnical Report for the project prepared by Geocon Incorporated The
recommendations contained in the text of the Geotechnical Report are a part of
the earthwork and grading specffications and shaU supersede the provisions
contained hereinafter in the case of conflict.
1.2 Prior to the commencement of grading, a geotechnical consultant (Consultant)
ShaU be employed for the purpose of observing earthwork procedures and testing
the fills for substantial conformance with the recommendations of the Geotech-
nical Report and these specifications. It wiU be necessary that the Consultant
provide adequate testing and observation semces so that he may determine that
m his opmion, the work was performed in substantial conformance with these
specifications. It shaU be the responsibility of the Contractor to assist the
Consultant and keep him apprised of work schedules and changes so that
personnel may be scheduled accordingly.
1.3 It ShaU be the sole responsibUity of the Contractor to provide adequate equipment
and methods to accompUsh the work in accordance with applicable grading codes
or agency ordmances, these specifications and the approved grading plans If in
the opmion of the Consultant, unsatisfactory conditions such as questionable soU
materials, poor moisture condition, inadequate compaction, adverse weather and
so forth, result m a quaUty of work not in conformance with these specifications
the Consultant wUl be empowered to reject the work and recommend to the
Owner that construction be stopped untU the unacceptable conditions are
corrected.
DEFINITIONS
2.1 0>v^er ShaU refer to the owner of the property or the entity on whose behalf the
gradmg work is bemg performed and who has contracted with the Contractor to
nave gradmg performed.
2.2 Contractor shaU refer to the Contractor performing the site grading work.
2.3 Civil Engineer or Engineer of Work shaU refer to the California licensed CivU
Engineer or consultmg firm responsible for preparation of the grading plans
surveying and verifymg as-graded topography.
2.4 Consultant shaU refer to the soU engineering and engineering geology
consulting fkm retained to provide geotechnical services for the project.
2.5 Soil Engineer shaU refer to a CaUfomia Ucensed CivU Engineer retained by the
Owner, who is experienced in the practice of geotechnical engineering. The SoU
Engmeer shaU be responsible for havmg quaUfied representatives on-site to
observe and test the Contractor's work for conformance with these specifications.
2.6 Engineering Geologist shaU refer to a CaUfomia Ucensed Engineermg Geologist
retamed by the Owner to provide geologic observations and recommendations
during the site grading.
2.7 Geotechnical Report shaU refer to a soU report (includmg aU addendums) which
may mclude a geologic reconnaissance or geologic mvestigation that was prepared
specificaUy for the development of the project for which these Recommended
Gradmg Specifications are mtended to apply.
MATERIALS
3.1 Materials for compacted fUl shaU consist of any soU excavated from the cut areas
or miported to the site that, m the opinion of the Consultant, is suitable for use
m construction of fUls. In general, fUl materials can be classified as soil fUls
soil-rock fUls or rock fUls, as defined below.
3.1.1 Soil fills are defined as fUls containing no rocks or hard lumps greater than
12 mches m maximum dimension and containing at least 40 percent by
weight of material smaUer than 3/4 inch m size.
3.1.2 Soil-rock fills are defined as fUls containing no rocks or hard lumps larger
than 4 feet m maximum dimension and containing a sufficient matrix oisoil
fUl to aUow for proper compaction oisoil fUl around the rock fragments or
hard lumps as specified in Paragraph 6.2. Oversize rock is defmed as
matenal greater than 12 inches.
3.1.3 Rock fills are defined as fUls containing no rocks or hard lumps larger than
3 feet m maxmium dimension and contaming little or no fines. Fines are
defmed as material smaUer than 3/4 inch in maximum dimension. The
quantity of fmes shaU be less than approximately 20 percent of the rock fUl
quantity.
3.2 Material of a perishable, spongy, or otherwise unsuitable nature as determined by
the Consultant shaU not be used in fiUs.
3.3 Materials used for fUl, either imported or on-site, shaU not contam hazardous
materials as defmed by the CaUfornia Code of Regulations, Title 22 Division 4
Chapter 30, Articles 9 and 10; 40CFR; and any other appUcable local, state or
federal laws. The Consultant shaU not be responsible for the identification or
analysis of the potential presence of hazardous materials. However, if
observations, odors or soU discoloration cause Consuhant to suspect the presence
of hazardous materials, the Consultant may request from the Owner the
termination of grading operations withm the affected area. Prior to resummg
grading operations, the Owner shaU provided a written report to the Consultant
mdicating that the suspected materials are not hazardous as defmed by appUcable
laws and regulations.
3.4 The outer 15 feet of soil-rock fUl slopes, measured horizontaUy, should be
composed of properly compacted soil fUl materials approved by the Consultant.
Rock m may extend to the slope face, provided that the slope is not steeper than
2:1 (horizontahvertical) and a soU layer no thicker than 12 mches is track-waUced
onto the face for landscapmg purposes. This procedure may be utUized, provided
It is acceptable to the governing agency. Owner and Consultant.
3.5 Representative samples of soU materials to be used for fUl shaU be tested m the
laboratoiy by the Consultant to determine the maximum density, optimum
moisture content, and, where appropriate, shear strength, expansion, and gradation
characteristics of the soU.
3.6 During grading, soU or groundwater conditions other than those identified in the
Geotechnical Report may be encountered by the Contractor. The Consultant shaU
be notified immediately to evaluate the significance ofthe unanticipated condition.
4 CLEARING AND PREPARING AREAS TO BE FILLED
4.1 Areas to be excavated and fUled shaU be cleared and grubbed. Clearing shaU
consist of complete removal above the ground surface of trees, stumps, brush,
vegetation, man-made structures and srniUar debris. Grubbing shaU consist of
removal of stumps, roots, buried logs and other unsuitable material and shaU be
performed in areas to be graded. Roots and other projections exceedmg 1-1/2
inches in diameter shaU be removed to a depth of 3 feet below the surface of the
ground. Borrow areas shaU be grubbed to the extent necessary to provide suitable
fiU materials.
4.2 Any asphalt pavement material removed during clearing operations should be
properly disposed at an approved off-site facUity. Concrete fragments which are
free of reinforcing steel may be placed in fUls, provided they are placed in
accordance with Section 6.2 or 6.3 of this document.
4.3 After clearing and grubbing of organic matter or other unsuitable material, loose
or porous soUs shaU be removed to the depth recommended in the Geotechnical
Report. The depth of removal and compaction shaU be observed and approved
by a representative of the Consultant. The exposed surface shaU then be plowed
or scarified to a mmunum depth of 6 inches and untU the surface is free from
uneven features that would tend to prevent uniform compaction by the equipment
to be used.
4.4 Where the slope ratio of the origmal ground is steeper than 6:1
(horizontahvertical), or where recommended by the ConsuUant, the original
ground should be benched in accordance with the foUowing illustration.
TYPICAL BENCHING DETAIL
FINISH GRADE
REMOVE is RECOM BT SOIL ENGINEER
FINISI-SURFACE
NO SCALE
NOTES: (1) Key width "B" should be a minUnum of 10 feet wide, or
sufficiently wide to permit complete coverage with the
compaction equipment used. The base of the key should be
graded horizontal, or incUned sUghtly into the natural slope.
(2) The outside of the bottom key should be below the topsoU
or unsuitable surficial material and at least 2 feet mto dense
formational material. Where hard rock is exposed in the bottom
of the key, the depth and configuration of the key may be
modified as approved by the Consultant.
4.5 After areas to receive fUl have been cleared, plowed or scarified, the surface
should be disced or bladed by the Contractor untU it is uniform and free from
large clods. The area should then be moisture conditioned to achieve the proper
moisture content, and compacted as recommended in Section 6.0 of these
specifications.
5 COMPACTION EQUIPMENT
5.1 Compaction of soil or soil-rock fUl shaU be accompUshed by sheepsfoot or
segmented-steel wheeled roUers, vibratory roUers, multiple-wheel pneumatic-tired
roUers, or other types of acceptable compaction equipment. Equipment shaU be
of such a design that it wUl be capable of compactmg the soil or soil-rock fUl to the
specified relative compaction at the specified moisture content.
5.2 Compaction of rock fiUs shaU be performed m accordance with Section 6.3.
6 PLACING, SPREADING AND COMPACTION OF FILL MATERIAL
6.1 Soil fUl, as defmed m Paragraph 3.1.1, shaU be placed by the Contractor m
accordance with the foUowing recommendations:
6.1.1 Soil fUl shaU be placed by the Contractor m layers that, when compacted,
should generaUy not exceed 8 inches. Each layer shaU be spread evenly and
shaU be thoroughly mixed during spreading to obtain uniformity of material
and moisture in each layer. The entire fUl shaU be constructed as a unit in
nearly level Ufts. Rock materials greater than 12 inches in maximum
dimension shaU be placed m accordance with Section 6.2 or 6.3 of these
specifications.
6.1.2 In general, the soil fUl shaU be compacted at a moisture content at or above
the optimum moisture content as determined by ASTM D1557-78.
6.1.3 When the moisture content of soil fUl is below that specified by the
Consultant, water shaU be added by the Contractor untU the moisture
content is in the range specified.
6.1.4 When the moisture content of the soil fUl is above the range specified by
the Consultant or too wet to achieve proper compaction, the soil fUl shaU
be aerated by the Contractor by bladmg/mixing, or other satisfactory
methods untU the moisture content is within the range specified.
6.1.5 After each layer has been placed, mixed, and spread evenly, it shaU be
thoroughly compacted by the Contractor to a relative compaction of at least
90 percent. Relative compaction is defined as the ratio (expressed in
percent) of the in-place dry density of the compacted fUl to the maximum
laboratory dry density as determined in accordance, with ASTM D1557-78.
Compaction shaU be continuous over the entire area, and compaction
equipment shaU make sufficient passes so that the specified minimum
density has been achieved throughout the entire fUl.
6.1.6 SoUs having an Expansion Index of greater than 50 may be used m fUls if
placed at least 3 feet below finish pad grade and should be compacted at
a moisture content generaUy 2 to 4 percent greater than the optimum
moisture content for the material.
6.1.7 Properly compacted soil fUl shaU extend to the design surface of fUl slopes.
To achieve proper compaction, it is recommended that fUl slopes be over-
buUt by at least 3 feet and then cut to the design grade. This procedure is
considered preferable to track-walkmg of slopes, as described in the
foUowing paragraph.
6.1.8 As an alternative to over-buUdmg of slopes, slope faces may be back-roUed
with a heavy-duty loaded sheepsfoot or vibratory roUer at maxunum 4-foot
fill height intervals. Upon completion, slopes should then be track-waked
with a D-8 dozer or simUar equipment, such that a dozer track covers aU
slope surfaces at least twice.
6.2 Soil-rock fUl, as defined m Paragraph 3.1.2, shaU be placed by the Contractor m
accordance with the foUowing recommendations:
6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dunension
may be mcorporated mto the compacted soil fUl, but shaU be Umited to the
area measured 15 feet minunum horizontaUy from the slope face and 5 feet
below fmish grade or 3 feet below the deepest utUity, whichever is deeper.
6.2.2 Rocks or rock fragments up to 4 feet m maximum dimension may either be
mdividuaUy placed or placed in windrows. Under certam conditions, rocks
or rock fragments up to 10 feet m maximum dimension may be placed
usmg simUar methods. The acceptabUity of placing rock materials greater
than 4 feet in maxmium dimension shaU be evaluated durmg grading, as
specific cases arise and shaU be approved by the Consultant prior to
placement.
6.2.3 For individual placement, sufficient space shaU be provided between rocks
to aUow for passage of compaction equipment.
6.2.4 For windrow placement, the rocks should be placed in trenches excavated
in properly compacted soil fUl. Trenches should be approximately 5 feet
wide and 4 feet deep in maximum dimension. The voids around and
beneath rocks should be fUled with approved granular soU having a Sand
Equivalent of 30 or greater and should be compacted by flooding
Wmdrows may also be placed utUizing an "open-face" method in lieu of the
trench procedure, however, this method should first be approved by the
Consultant.
6.2.5 Windrows should generally be paraUel to each other and may be placed
either paraUel to or perpendicular to the face of the slope depending on the
site geometry. The mmunum horizontal spacing for windrows shaU be
12 feet center-to-center with a 5-foot stagger or offset from lower courses
to next overlymg course. The minunum vertical spacmg between windrow
courses shaU be 2 feet from the top of a lower wmdrow to the bottom of
the next higher windrow.
6.2.6 AU rock placement, fUl placement and floodmg of approved granular soU
in the wmdrows must be contmuously observed by the Consultant or his
representative.
6.3 Rock fUls, as defmed m Section 3.1.3, shaU be placed by the Contractor m
accordance with the foUowing recommendations:
6.3.1 The base of the rock fUl shaU be placed on a slopmg surface (minunum
slope of 2 percent, maxmium slope of 5 percent). The surface shaU slope
toward suitable subdrainage outlet facUities. The rock fUls shaU be provided
with subdrams during construction so that a hydrostatic pressure buUdup
does not develop. The subdrams shaU be permanently connected to
controUed drainage facUities to control post-construction mfUtration of
water.
6.3.2 Rock fUls shaU be placed in Ufts not exceeding 3 feet. Placement shaU be
by rock trucks traversing previously placed Ufts and dumping at the edge of
the currently placed Uft. Spreadmg of the rock fUl shaU be by dozer to
facUitate jrarf/i^ of the rock. The roc^ fUl shaU be watered heavUy durmg
placement. Watermg shaU consist of water trucks traversmg in front of the
current rock Uft face and spraymg water contmuously durmg rock
placement. Compaction equipment with compactive energy comparable to
or greater than that of a 20-ton steel vibratory roUer or other compaction
equipment providing suitable energy to achieve the requUed compaction or
deflection as recommended in Paragraph 6.3.3 shaU be utUized. The number
of passes to be made wiU be determined as described m Paragraph 6.3.3.
Once a rock fUl Uft has been covered with soU fUl, no additional rock fUl
Ufts wUl be permitted over the soU fUl.
6.3.3 Plate bearmg tests, in accordance with ASTM Dl 196-64, may be performed
m both the compacted soil fUl and in the rock fUl to aid in determming the
number of passes of the compaction equipment to be performed. If
performed, a minimum of three plate bearmg tests shaU be performed in
the properly compacted soil fUl (minimum relative compaction of 90
percent). Plate bearing tests shaU then be performed on areas of rock fUl
having two passes, four passes and six passes of the compaction equipment,
respectively. The number of passes required for the rock fUl shaU be
determined by comparing the results of the plate bearing tests for the ^ozY
fUl and the rock fUl and by evaluating the deflection variation with number
of passes. The required number of passes of the compaction equipment
wUl be performed as necessary untU the plate bearing deflections are equal
to or less than that determined for the properly compacted soU fUl. In no
case wUl the required number of passes be less than two.
6.3.4 A representative of the Consultant shaU be present during rock fUl
operations to verify that the mmimum number of "passes" have been
obtained, that water is bemg properly applied and that specified procedures
are being foUowed. The actual number of plate bearing tests wUl be
determmed by the Consultant during grading. In general, at least one test
should be performed for each approximately 5,000 to 10,000 cubic yards of
rock fUl placed.
6.3.5 Test pits shaU be excavated by the Contractor so that the Consultant can
state that, in his opmion, sufficient water is present and that voids between
large rocks are properly fUled with smaUer rock material. In-place density
testuig wUl not be required m the rock fiUs.
6.3.6 To reduce the potential for "piping" of fmes mto the rock fUl from overlymg
soil fUl material, a 2-foot layer of graded fUter material shaU be placed
above^ the uppermost lift of rock fUl. The need to place graded fUter
material below the rock should be determmed by the Consultant prior to
commencmg gradmg. The gradation of the graded fUter material wUl be
determmed at the time the rock fUl is being excavated. Materials typical of
the rock fiU should be submitted to the Consultant m a tunely manner, to
aUow design of the graded fUter prior to the commencement of rock m
placement.
6.3.7 AU rock fUl placement shaU be continuously observed during placement by
representatives of the Consultant.
7 OBSERVATION AND TESTING
7.1 The Consultant shaU be the Owners representative to observe and perform tests
durmg clearmg, grubbing, fUling and compaction operations. In general, no more
than 2 feet m vertical elevation of soil or soil-rock fUl shaU be placed without at
least one field density test bemg performed within that inten^al. In addition, a
minimum of one field density test shaU be performed for every 2,000 cubic yards
of soil or soil-rock fUl placed and compacted.
7.2 The Consultant shaU perform random field density tests of the compacted soil or
soil-rock fUl to provide a basis for expressing an opmion as to whether the fUl
material is compacted as specified. Density tests shaU be performed in the
compacted materials below any disturbed surface. When these tests mdicate that
the density of any layer of fUl or portion thereof is below that specffied, the
particular layer or areas represented by the test shaU be reworked untU the
specified density has been achieved.
7.3 During placement of rock fiU, the Consuhant shaU verify that the minimum
number of passes have been obtained per the criteria discussed in Section 6.3.3.
The Consultant shaU request the excavation of observation pits and may perform
plate bearing tests on the placed rock fUls. The observation pits wUl be excavated
to provide a basis for expressing an opinion as to whether the rock fUl is properly
seated and sufficient moisture has been applied to the material. If performed,
work on the site. The Contractor shaU take remedial measures to prevent erosion
of freshly graded areas untU such tune as permanent dramage and erosion control
features have been mstaUed. Areas subjected to erosion or sedimentation shaU
be properly prepared m accordance with the Specifications prior to placmg
additional fUl or structures.
8.2 After completion of grading as observed and tested by the Consultant, no further
excavation or fUUng shaU be conducted except m conjunction with the services of
the Consultant.
9 CERTIFICATIONS AND FINAL REPORTS
9.1 Upon completion of the work. Contractor shaU furnish Owner a certification by
the CivU Engineer statmg that the lots and/or buUding pads are graded to within
0.1 foot verticaUy of elevations shown on the grading plan and that aU tops and
toes of slopes are withm 0.5 foot horizontaUy of the positions shown on the
grading plans. After mstaUation of a section of subdrain, the project CivU
Engmeer should survey its location and prepare an as-built plan of the subdram
location. The project CivU Engmeer should verify the proper outlet for the
subdrains and the Contractor should ensure that the drain system is free of
obstructions.
9.2 The Owner is responsible for furnishing a fmal as-graded soU and geologic report
satisfactory to the appropriate governing or accepting agencies. The as-graded
report should be prepared and signed by a California licensed CivU Engineer
experienced in geotechnical engineering and by a galifornia Certified Engmeermg
Geologist, indicating that the geotechnical aspects of the grading were performed
m substantial conformance with the Specifications or_approved changes to the
Specifications.
Geocon Incorporated Fonn, Revision date: 06/OA/90
c c
GEOCON
INCORPORATED
Geotechnical Engineers and
•Engineering Geologists
FUe No. 04367-04-02
August 8, 1990
The Fieldstone Company
5465 Morehouse Drive, Suite 250
San Diego, CaUfornia 92121
Attention: Mr. John Barone
Subject: RANCHO SANTA FE ROAD REALIGNMENT
CARLSBAD, CALIFORNLA
ADDENDUM TO SUPPLEMENTAL SOIL AND GEOLOGIC
INVESTIGATION, DATED JANUARY 8, 1990
Gentlemen:
In accordance with your request, this addendum letter is written in response to the City of
Carlsbad review of our Supplemental Soil and Geologic Investigation, dated January 8, 1990.
Based on our review ofthe response letter of transmittal, this addendum has been prepared
to include a revision of Figure 1, Vicmity Map, which delineates the approximate Umits of
the subject project. This addendum also mcorporates the registration seals of the project
geotechnical engineer and engmeermg geologist involved with this project.
Should you have any questions regarding this letter, or if we may be of further service,
please contact the undersigned at your convenience.
Very truly yours,
(2) addressee
(4) Project Design Consultants
Attention: Mr. Brad Smith
Monte L. MurbacrT""" ^
Project Geologist
6960 Flanders Drive
San Diego, CA 92121-2974
619 558-6900
FAX 619 558-6159
File No. 04367-04-02
Figure 1