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UniSpec II-Store Planning 033012
SECTION 02320 - EXCAVATING, BACKFILLING, AND COMPACTING
PART 1 - GENERAL
1.1 SUMMARY
A. Section Includes:
1. Trenching and backfilling for utilities.
B. Related Sections
1. Division 3 – Subbase requirements for granular subbase below building slabs.
1.2 REFERENCES
A. The publications listed below form a part of this specification to the extent referenced. Publications are referenced
within the text by the basic designation only.
B. ASTM International (ASTM)
1. ASTM D 422 - Standard Test Method For Particle Size Analysis of Soil
2. ASTM D 698 - Laboratory Compaction Characteristics of Soil Using Standard Effort (12,400 ft-lbf/ft3
(600 kN.m/m3))
3. ASTM D 1557 - Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft3
(2,700 Kn.m/m3))
4. ASTM D 2321 - Standard Practice for Underground Installation of Thermoplastic Pipe for Sewers and
Other Gravity-Flow Applications.
5. ASTM D 2922 - Density of Soil and Soil-Aggregate In Place by Nuclear Methods (Shallow Depth)
6. ASTM D 4318 - Liquid Limit, Plastic Limit, and Plasticity Index of Soils
C. American Association of State Highway and Transportation Officials (AASHTO)
1. AASHTO T 88 - Particle Size Analysis of Soils
D. National Fire Protection Association (NFPA)
1. NFPA 70 - National Electrical Code
E. American Water Works Association (AWWA)
1. AWWA C200 - Standard For Steel Water Pipe - 6 In. (150 Mm) And Larger
2. AWWA C206 - Field Welding Of Steel Water Pipe
1.3 QUALITY ASSURANCE
A. A Construction Testing Laboratory (CTL), selected and paid for by the Owner, will be retained to perform
construction testing on site.
1. The CTL shall prepare test reports that indicate test location, elevation data, and test results. Owner, Civil
Engineering Consultant, and Contractor shall be provided with copies of reports within 96 hours of time
that test was performed. In event that test performed fails to meet Specifications, the construction testing
laboratory shall notify Owner and Contractor immediately.
2. Costs related to retesting due to failures shall be paid for by the Contractor at no additional expense to
Owner. Contractor shall provide free access to site for testing activities.
3. Quality assurance testing will be conducted in accordance with Paragraph “Field Testing” in Part 3
hereinafter.
B. Satisfactory Materials: ASTM D 2487 soil classification groups GW, GP, GM, SW, SP, SM, ML, CL, CH, MH,
SC, GC, or a combination of these group symbols.
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1. Fill material shall further conform to the plasticity index and liquid limits (PI and LL) specified in
Paragraph FILLING hereinafter.
2. Satisfactory materials shall be free of rock or gravel larger than allowed for fill or backfill material as
specified hereinafter or as shown on the drawings.
3. Satisfactory materials shall contain no debris, waste, frozen materials, vegetation, and other deleterious
matter.
4. Unless specifically stated otherwise in "Foundation Subsurface Preparation" on the Drawings, the
following table stipulates maximum allowable values for plasticity index (PI) and liquid limit (LL) of
satisfactory materials to be used as fill in specified areas:
Location PI LL
Building area (below upper four feet) 20 50
Building area (upper four feet) 12 40
(References to depth are to finished floor elevation)
C. Unsatisfactory Materials: Materials which do not comply with the requirements for satisfactory materials are
unsatisfactoy.
1. Unsatisfactory materials also include man-made fills; trash; refuse; backfills from previous construction;
and material classified as satisfactory materials which contains root and other organic matter or frozen
material. The CTL shall be notified of any contaminated materials.
2. Unsatisfactory materials also include satisfactory materials not maintained within 2 percent of optimum
moisture content at time of compaction.
1.4 SUBMITTALS
A. Submit 30-pound sample of each type of off-site fill material that is to be used at the site in airtight containers to
the construction testing laboratory or submit gradation and certification of aggregate material that is to be used at
the site to the construction testing laboratory for review.
B. Submit certification that all material obtained from off-site sources complies with specification requirements.
C. Submit name of each material supplier and specific type and source of each material. Change in source
throughout project requires approval of Owner.
D. Submit Dewatering Plans upon request by Owner.
E. Shop drawings or details pertaining to excavating and filling are not required unless otherwise shown on the
Drawings or if contrary procedures to Construction Documents are proposed.
F. Shop drawings or details pertaining to site utilities are not required unless required by regulatory authorities or
unless uses of materials, methods, equipment, or procedures that are contrary to The Drawings or Specifications
are proposed. Do not perform work until Owner has accepted required shop drawings.
PART 2 - PRODUCTS
2.1 SOIL AND ROCK MATERIALS
A. Fill and Backfill. Satisfactory materials excavated from the site.
B. Imported Fill Material: Satisfactory material provided from offsite borrow areas when sufficient satisfactory
materials are not available from required excavations.
C. Trench Backfill: ASTM D 2321 unless otherwise specified or shown on the drawings.
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D. Building Subbase Material: Subbase for building and appurtenances slabs on ground is specified in Section
03314 as applicable.
E. Bedding: Aggregate Type as indicated on the plans or naturally or artificially graded mixture of natural or
crushed gravel, crushed stone, and natural or crushed sand; ASTM D 2940; except with 100 percent passing a 1-
inch sieve and not more than 8 percent passing a No.200 sieve.
F. Drainage Fill: Washed, narrowly graded mixture of crushed stone, or crushed or uncrushed gravel; ASTM D 448;
coarse-aggregate grading Size 57; with 100 percent passing a 1-1/2- inch sieve and 0 to 5 percent passing a No.8
sieve.
G. Filter Material: Narrowly graded mixture of natural or crushed gravel, or crushed stone and natural sand;
ASTM D 448; coarse-aggregate grading Size 67; with 100 percent passing a 1-inch sieve and 0 to 5 percent
passing a No.4 sieve.
2.2 EQUIPMENT
A. Transport off-site materials to project using well-maintained and operating vehicles. Once on site, transporting
vehicles shall stay on designated haul roads and shall at no time endanger improvements by rutting, overloading,
or pumping.
2.3 SOURCE QUALITY CONTROL
A. Laboratory testing of materials proposed for use in the project shall be by the Wal-Mart Construction Testing
Laboratory at no cost to Contractor. The Contractor shall provide samples of material obtained off-site.
B. Following tests shall be performed on each type of on-site or imported soil material used as compacted fill:
1. Moisture and Density Relationship: ASTM D 698 or ASTM D 1557.
2. Mechanical Analysis: AASHTO T 88 or ASTM D422.
3. Plasticity Index: ASTM D 4318
PART 3 - EXECUTION
3.1 PREPARATION
A. Identify required lines, levels, contours, datum, elevations, and grades necessary for construction as shown on the
drawings.
B. Locate and identify existing utilities that are to remain and protect from damage.
C. Maintain in operating condition existing utilities, previously installed utilities, and drainage systems encountered
in utility installation. Repair surface or subsurface improvements shown on The Drawings.
D. Verify location, size, elevation, and other pertinent data required making connections to existing utilities and
drainage systems as indicated on The Drawings.
3.2 GENERAL EXCAVATION
A. Classification of Excavation: The Contractor shall assure himself by site investigation or other necessary means
that he is familiar with the type, quantity, quality, and character of excavation work to be performed. Excavation
shall be considered unclassified excavation, except as indicated in the Contract Documents.
B. Shore, brace, and drain excavations as necessary to maintain excavation as safe, secure, and free of water at all
times.
C. Place satisfactory excavated material into project fill areas.
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D. Unsatisfactory excavated material shall be disposed of in manner and location that is acceptable to Owner and
local governing agencies.
E. Perform excavation using capable, well-maintained equipment and methods acceptable to Owner and local
governing agencies.
3.3 TRENCHING EXCAVATION FOR UTILITIES
A. Sawcut existing concrete slab and hand dig trench at proper width and depth for laying pipe, conduit, or cable.
Cut trench banks vertical, if possible, and remove stones from bottom of trench as necessary to avoid
point-bearing. Over-excavate wet or unstable soil, if encountered, from trench bottom as necessary to provide
suitable base for continuous and uniform bedding. Replace over-excavation with satisfactory material and dispose
of unsatisfactory material.
B. Trench excavation sidewalls shall be sloped, shored, sheeted, braced, or otherwise supported by means of
sufficient strength to protect workmen in accordance with applicable rules and regulations established for
construction by the Department of Labor, Occupational Safety and Health Administration (OSHA), and by local
ordinances. Lateral travel distance to exit ladder or steps shall not be greater than 25 feet in trenches 4 feet or
deeper.
C. Perform trench excavation as indicated on the Drawings for specified depths. During excavation, stockpile
materials suitable for backfilling in orderly manner far enough from bank of trench to avoid overloading, slides, or
cave-ins.
D. Remove excavated materials not required or not satisfactory as backfill or embankments and waste off-site or at
on-site locations approved by the Owner and in accordance with governing regulations.
E. Accurately grade trench bottom to provide uniform bearing and support for each section of pipe on bedding
material at every point along entire length except where necessary to excavate for bell holes, proper sealing of
pipe joints, or other required connections. Dig bell holes and depressions for joints after trench bottom has been
graded. Dig no deeper, longer, or wider than needed to make joint connection properly.
F. Trench width below top of pipe shall not be less than 12 inches nor more than 18 inches wider than outside
surface of pipe or conduit that is to be installed to designated elevations and grades. Other trench width for pipe,
conduit, or cable shall be least practical width that will allow for proper compaction of trench backfill.
G. Trench depth requirements measured from finished slab shall meet the following requirements or applicable codes
and ordinances, whichever is more stringent:
1. Sanitary Sewer: Elevations and grades as indicated on the drawings and as specified in Section 02535.
3.4 PIPE BEDDING
A. Excavate trenches for pipe or conduit to 4 inches below bottom of pipe and to the width as specified herein. Place
4 inches of bedding material, compact in bottom of trench, and shape to conform to lower portion of pipe barrel.
3.5 TRENCH BACKFILLING
A. Materials used for trench backfill shall comply with requirements as specified herein.
B. Backfill and compact in accordance with fill and compaction requirements in accordance with ASTM D 2321
unless otherwise shown on the drawings.
C. Do not backfill trenches until required tests are performed and utility systems comply with and are accepted by
applicable governing authorities.
D. Backfill trenches as shown on the Drawings.
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E. Do not backfill over porous, wet, frozen, or spongy subgrade surfaces.
3.6 COMPACTION
A. Compact as follows:
Percent of Maximum Laboratory Density
Location ASTM D698 ASTM D1557
Utility Trench Backfill 98 95
B. Maintain moisture content of not less than 1 percent below and not more than 3 percent above optimum moisture
content of fill materials to attain required compaction density.
C. Exercise proper caution when compacting immediately over top of pipes or conduits. Water jetting or flooding is
not permitted as method of compaction.
D. Corrective Measures for Non-Complying Compaction: Remove and recompact deficient areas until proper
compaction is obtained. Areas continually failing shall be stabilized at no additional cost to Owner. Notify the
Architect of Record and the Wal-Mart Construction Manager should soil stabilization be required.
3.7 MAINTENANCE OF SUBGRADE
A. Verify finished subgrades to ensure proper elevation and conditions for construction above subgrade.
B. Remove areas of finished subgrade found to have insufficient compaction density to depth necessary and replace
in manner that will comply with compaction requirements by use of material with CBR or LBR equal to or better
than that specified on the drawings. Surface of subgrade after compaction shall be firm, uniform, smooth, stable,
and true to grade and cross-section.
3.8 BORROW AND SPOIL SITES
A. Comply with NPDES and local erosion control permitting requirements for any and all on-site and off-site,
disturbed spoil and borrow areas. Upon completion of spoil or borrow operations, clean up spoil or borrow areas
in a neat and reasonable manner to the satisfaction of Owner or off-site property owner, if applicable.
3.9 QUALITY ASSURANCE TESTING AND INSPECTION
A. Responsibilities: Unless otherwise specified, quality control tests and inspection specified below will be
conducted by the Owner’s Construction Testing Laboratory (CTL) at no cost to the Contractor in accordance with
Section 01458. The Contractor shall perform additional testing or inspection as considered necessary by the
Contractor for assurance of quality control.
B. Field testing, frequency, and methods may vary as determined by and between the Owner and the CTL.
C. Work shall be performed by a Special Inspector – Technical I unless specified otherwise. Report of testing and
inspection results shall be made upon the completion of testing.
D. Classification of Materials: Perform test for classification of materials used and encountered during construction
in accordance with ASTM D2488 and ASTM D2487.
E. Laboratory Testing Of Materials: Perform laboratory testing of materials (Proctor, Sieve Analysis, Atterberg
Limits, Consolidation Test, etc.) as specified.
F. Field Density Tests.
1. Utility Trench Backfill: Intervals not exceeding 30-feet of trench for first and every other 8-inch lift of
compacted trench backfill.
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2. Test Method: In-place nuclear density, ASTM D 2922 (Method B-Direct Transmission).
G. Corrective Measures For Non-Complying Compaction: Remove and recompact deficient areas until proper
compaction is obtained at no additional expense to Owner. Adjust moisture content as necessary to conform to
the requirements of this section.
H. Observation and Inspection:
1. Observe all subgrades/excavation bases below slabs and verify design bearing capacity is achieved as
required. Work shall be performed by a Special Inspector – Technical II.
2. Observe and document presence of groundwater within excavations.
END OF SECTION