35 73 13.pdf

DEVILS LAKE CITY EMBANKMENTS - PHASE 3, EMBANKMENT RAISE AND EXTENSION,

& LAKEWOOD AND HIGHWAY 20 PUMP STATIONS

SECTION TABLE OF CONTENTS

DIVISION 35 - WATERWAY AND MARINE CONSTRUCTION

SECTION 35 73 13

EARTHWORK

01/08

PART 1 GENERAL

1.1 REFERENCES

1.2 SUBMITTALS

1.3 SUBSURFACE DATA

1.4 DEFINITIONS

1.4.1 Embankment

1.4.2 Embankment Material

1.4.3 Existing Embankment

1.4.4 Satisfactory and Unsatisfactory Materials

1.4.5 Cohesionless and Cohesive Materials

1.4.6 Marl

1.4.7 Proctor

1.5 NOT USED

1.6 SYSTEM DESCRIPTION

1.6.1 Haul Roads

1.6.2 Stockpiling from Approved Borrow Sources

PART 2 PRODUCTS

2.1 MATERIALS

2.1.1 Granular Fill

2.1.2 Random Fill

2.1.3 Embankment Material

2.1.3.1 Select Impervious Fill

2.1.3.2 Impervious Fill

2.1.3.3 POTENTIAL BORROW SOURCES LISTED

2.1.4 Sand Drain and Filter Stone

2.1.4.1 Sand Drain

2.1.4.2 Filter Stone

2.1.4.3 Sand Drain and Filter Stone Sources

2.1.5 Topsoil

2.1.6 Granular Fill under Structures

PART 3 EXECUTION

3.1 LINES AND GRADES

3.2 CONDUCT OF WORK

3.3 FROZEN MATERIALS

3.4 CLASSIFICATION OF SOIL MATERIALS

3.5 STOCKPILES

3.6 UTILIZATION OF EXCAVATED MATERIALS

3.7 BORROW MATERIAL

3.7.1 Borrow Sites

3.7.1.1 USACE Potential Borrow Sites

3.7.1.2 Borrow Site Submittals

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3.7.1.3 Other Borrow Sites

3.7.2 Excavation and Borrow Pits

3.7.3 Utilization of Excavated Materials

3.8 EXCAVATION

3.8.1 Excavation Advancement

3.8.2 Ditches, Gutters, and Channel Changes

3.8.3 Inspection Trench

3.8.4 Marl Inspection Trench

3.8.4.1 Marl Inspection Trench Excavation and Observation

3.8.4.2 Marl Inspection Trench Backfill

3.8.4.3 Marl Inspection Trench Location

3.9 STRUCTURES

3.9.1 General

3.9.1.1 Granular fill under Structures

3.9.2 Over Depth Excavation

3.9.3 Drainage

3.9.3.1 Dewatering

3.9.4 Foundation Compaction

3.9.5 Backfilling

3.10 STRIPPING

3.10.1 Stripped Material Suitable For Use As Topsoil

3.11 SUBGRADE PREPARATION

3.11.1 Subgrade Correction

3.11.2 Marl Subgrade Correction

3.11.3 Marl Subgrade Preservation

3.12 PRAIRIE POTHOLES

3.13 EMBANKMENT MATERIAL PLACEMENT

3.13.1 Inspection and Approval

3.13.2 Rate of Placement

3.13.3 Spreading

3.13.4 Partial Fill Sections

3.13.5 Select Impervious Fill and Impervious Fill

3.13.5.1 Select Impervious Fill

3.13.5.2 Impervious Fill

3.14 SAND DRAIN AND FILTER STONE PLACEMENT

3.14.1 Sand Drain

3.14.2 Filter Stone

3.15 TOPSOIL PLACEMENT

3.16 MOISTURE CONTROL

3.16.1 Select Impervious Fill

3.16.2 Impervious Fill

3.16.3 Sand Drain

3.16.4 Filter Stone

3.17 COMPACTION

3.17.1 Placement And Compaction

3.18 COMPACTION EQUIPMENT

3.18.1 Tamping Rollers

3.18.2 Vibratory Rollers

3.18.3 Rubber-tired Rollers

3.18.4 Power Tampers

3.19 SLIDES

3.20 TESTING

3.20.1 General

3.20.2 Field Density Tests

3.20.3 Proctor Tests

3.20.4 Treatment of Oversize Particles for Density Tests

3.20.5 Corrective Action

3.20.6 Sampling

3.20.7 Testing Schedule

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3.20.7.1 Select Impervious Fill and Impervious Fill Testing

3.20.7.2 Sand Drain Testing

3.20.7.3 Select Impervious Fill and Impervious Fill Density Tests

3.20.7.4 Sand Drain Density Tests

3.20.7.5 Granular Fill, Random Fill, Satisfactory Fill

3.20.7.6 Moisture Content Tests

3.21 NUCLEAR DENSITY TESTING EQUIPMENT

3.22 FINISHING

3.23 INCLINOMETERS, SETTLEMENT PLATES and REFERENCE POINTS

3.23.1 Inclinometers

3.23.2 Settlement Plates

3.23.3 Reference Points

-- End of Section Table of Contents --

SECTION 35 73 13 Page 3 W912ES-11-B-0005

SECTION 35 73 13

EARTHWORK

01/08

PART 1 GENERAL

1.1 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only.

ASTM INTERNATIONAL (ASTM)

ASTM C 117 (2004) Standard Test Method for Materials Finer than 75-um (No. 200) Sieve in Mineral Aggregates by Washing

ASTM C 136 (2006) Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates

ASTM D 1140 (2000; R 2006) Amount of Material in Soils Finer than the No. 200 (75-micrometer) Sieve

ASTM D 1556 (2007) Density and Unit Weight of Soil in Place by the Sand-Cone Method

ASTM D 2167 (2008) Density and Unit Weight of Soil in Place by the Rubber Balloon Method

ASTM D 2216 (2010) Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass

ASTM D 2487 (2010) Soils for Engineering Purposes (Unified Soil Classification System)

ASTM D 2488 (2009a) Description and Identification of Soils (Visual-Manual Procedure)

ASTM D 3017 (2005) Water Content of Soil and Rock in Place by Nuclear Methods (Shallow Depth)

ASTM D 422 (1963; R 2007) Particle-Size Analysis of Soils

ASTM D 4318 (2010) Liquid Limit, Plastic Limit, and Plasticity Index of Soils

ASTM D 4564 (2008) Standard Test Method for Density and Unit Weight of Soil in Place by the Sleeve Method

ASTM D 4718 (1987; R 2007)Standard Practice for Correction of Unit Weight and Water Content for Soils Containing Oversize

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Particles

ASTM D 6938 (2010) Standard Test Method for In-Place Density and Water Content of Soil and Soil-Aggregate by Nuclear Methods (Shallow Depth)

ASTM D 698 (2007e1) Laboratory Compaction Characteristics of Soil Using Standard Effort (12,400 ft-lbf/cu. ft. (600 kN-m/cu. m.))

NORTH DAKOTA DEPARTMENT OF TRANSPORTATION (NDDOT)

NDDOT 816 (2008) Standard Specifications for Road and Bridge Construction - Aggregates

1.2 SUBMITTALS

Government approval is required for submittals with a "G" designation;

submittals not having a "G" designation are for information only. When used, a designation following the "G" designation identifies the office that will review the submittal for the Government. The following shall be submitted in accordance with Section 01 33 00 SUBMITTAL PROCEDURES:

SD-01 Preconstruction Submittals

Work Plan; G

The Contractor shall submit a plan indicating the intended sequence of work.

The plan shall include starting and stopping locations of embankment excavations. The plan shall clearly indicate the extents of the existing embankment to be under excavation at any one time.

The plan shall include the means and methods that will be used for each of the embankment construction operations including stripping, excavation, placement and compaction of all materials, inspection trench excavation, marl inspection trench excavation, subgrade correction and marl subgrade correction.

The plan shall address risks to the schedule and the means and methods that will be used to mitigate those risks to keep the project on schedule. Risks to consider include weather, productivity, ground conditions including unsatisfactory marl, material supply, subcontractor reliability, labor or equipment issues.

The plan shall include crew composition for each embankment construction operation, indicating the size and number of each equipment type.

The work may not begin until the plan is approved by the Contracting Officer.

Shoring and Sheeting Plan; G

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Submit drawings and calculations, certified by a registered professional engineer, describing the methods for shoring and sheeting of excavations. Drawings shall include shoring and sheeting material sizes and types, arrangement of members including any anchorage, location of shoring and sheeting and excavation of soils, and the sequence and method of installation and removal. Calculations shall include data and references used.

Groundwater Control; G

Submit procedures for accomplishing groundwater control. The plan shall include the estimated flows, inlet grading configuration, number of primary and backup pumps to be provided, outlet line sizes, and planned outlet discharge locations.

Action and Response Plan; G

Submit 15 days after award. The Contractor shall submit for approval a plan that addresses the intended measures to be taken to mitigate and immediately react to any slope or seepage failures. The plan should address intended stockpiling procedures in the vicinity of active work areas, type of materials and equipment to be stockpiled (e.g. granular fill, gravel, rock, sand, steel sheet piling, dewatering wells/pumps) that will be used should any type of failure begin to occur. The plan shall clearly outline the intended mitigation measures to be taken for various type of slope and seepage failures. Excavation work may not be started until the plan is approved by the Contracting Officer. Action and Response Plan Minimum Requirements:

a. Address anticipated problem areas and clearly state the limits of any open excavation areas.

b. Address actions to be taken in the excavation areas for shutdown i.e. weekends, overnight etc.

c. Address emergency measures for slope and seepage failures. This must include stockpiled material to stabilize embankment with amount of time, equipment and material quantities needed to completely fill any open excavations.

d. Contractor must provide site specific equipment and personnel available to immediately respond to any emergencies regarding the embankment.

e. Provide emergency checklist.

f. Provide emergency calling tree.

g. Not used.

h. Provide the steps to re-establish normal operations.

SD-03 Product Data

INSTRUMENTATION INSTALLATION PLAN; G

The Contractor shall submit a plan indicating the intended

SECTION 35 73 13 Page 6 W912ES-11-B-0005 sequence of work, to include materials and installation methods.

POTENTIAL BORROW SOURCES LISTED; G

Proposed source of borrow material. Advance notice on the opening of excavation or borrow areas.

CONTRACTOR PROPOSED BORROW SOURCE; G

If the proposed borrow source is not one of those listed as a potential borrow source under paragraph POTENTIAL BORROW SOURCES LISTED, the Contractor shall submit the information required for

POTENTIAL BORROW SOURCES LISTED.

SD-06 Test Reports

Testing; G

A summary of testing results indicated in Paragraph TESTING shall be submitted within 24 hours of conclusion of physical tests, 3 copies of test results, including calibration curves and results of calibration tests. Results of testing at the borrow source.

The Contracting Officer shall be informed of test results daily for direction on corrective action required. Draft copies of field testing results shall be furnished to the Contracting Officer on a frequent and regular basis as directed, but do not need to be formally transmitted through the submittal process.

Daily Report Forms shall be completed and submitted as a supplement to the Daily QC Report.

Borrow Source Testing; G

Within 24 hours of conclusion of physical tests, 3 copies of test results, including calibration curves and results of calibration tests. Results of testing at the borrow site.

Daily Report Forms; G

A compilation of the daily report forms for earthwork observation and inspection trench observations ordered by date shall be submitted when the work is substantially complete. Preliminary copies shall be furnished to the Contracting Officer on a weekly or monthly basis as directed, but do not need to be formally transmitted through the submittal process.

Settlement Plates (Optional item); G

The contractor shall submit for approval, locations in which adjustment in quantities will be made as a result of foundation settlement.

SD-07 Certificates

Testing; G

Qualifications of the Corps validated commercial testing laboratory or the Contractor's validated testing facilities.

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1.3 SUBSURFACE DATA

Soil boring logs are shown in the drawings. Subsurface data including soil boring logs and laboratory test data for the project site and potential borrow sources are available for inspection in the Office of the District Engineer, 180 Fifth Street East, Suite 700, St. Paul, Minnesota 55101-1678.

1.4 DEFINITIONS

1.4.1 Embankment

Embankment refers to the earth structure required to be built under the terms of this contract by the placement of Embankment Material.

1.4.2 Embankment Material

Embankment material, as used in these specifications, is defined as the earth fill portions of the embankment and includes all types of earth fill and filter materials for the embankment, and all other specified or directed earth fills within the limits of the embankment, excepting those stone and bedding materials used for slope protection, which are described in Section 35 31 19.00 13 SLOPE PROTECTION.

1.4.3 Existing Embankment

Existing Embankment refers to earth structures existing prior to the work of this contract, built by others for the purpose of providing roadway or flood protection grades.

1.4.4 Satisfactory and Unsatisfactory Materials

Satisfactory materials shall be of a character and quality satisfactory for the purpose intended, and meet the applicable material specifications.

Satisfactory Materials include all soils except these classified in ASTM D 2487 as PT, OH, OL, MH and CH. Satisfactory material shall be free from ice, snow, frozen earth, trash, debris, organic material, and stones larger than 3 inches in any dimension.

Unsatisfactory material is all material not meeting the above satisfactory material requirements.

1.4.5 Cohesionless and Cohesive Materials

Cohesionless materials include materials classified in ASTM D 2487 as GW, GP, SW, and SP.

Cohesive materials include materials classified as GC, SC, ML, CL, MH, and CH. Materials classified as GM and SM will be identified as cohesionless only when the fines are nonplastic.

1.4.6 Marl

Marl consists of fresh water sedimentary deposits of calcium carbonate, often with varying percentages of calcareous fine sand, silt, clay and shell fragments. These deposits are unconsolidated, so marl is usually lightweight. Marl is usually white or light-gray in color with consistency usually ranging from soft paste to spongy. It may also contain organic material, or inorganic soils. Marl will be encountered in some portions of the embankment foundation at varying depths and thicknesses.

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Marl can be either satisfactory or unsatisfactory depending on the water content and location. Marl, with a water content such that it will not support the operation of construction equipment, exposed by stripping or excavation, in an area where construction equipment needs to operate, is unsatisfactory.

1.4.7 Proctor

Degree of compaction required is expressed as a percentage of the maximum density obtained by the test procedure presented in ASTM D 698. The maximum density is hereafter abbreviated as the "Standard Proctor" or "Proctor" value.

1.5 NOT USED

1.6 SYSTEM DESCRIPTION

1.6.1 Haul Roads

Haul roads shall be constructed as approved. They shall be designed to maintain the intended traffic, to be free draining and shall be maintained in good condition throughout the contract period, unless otherwise directed. Haul roads within the area of contact between the embankment and its foundation and abutments shall be removed and the area shall be treated as specified in this Section.

1.6.2 Stockpiling from Approved Borrow Sources

When the excavation from approved borrow sources progresses at a faster rate than placement in the fill is being accomplished, such excavated material shall be stockpiled at approved locations adjacent to the work until its use is authorized. No payment will be made for such stockpiling nor for the reloading and hauling of this material to its final position in the embankment.

PART 2 PRODUCTS

2.1 MATERIALS

The origin of any fill material in no way determines where it may be used in the embankment. Embankment Materials shall be secured from required excavations and from borrow sources. The intention is to use the most suitable materials obtainable from the borrow sources. Material to be wasted will be specifically designated at the time the material is excavated. Materials containing brush, roots, sod or other perishable materials will not be considered suitable. The suitability of the materials shall be subject to approval and their disposition in the embankment will be as directed. Excavate in the borrow areas in the location determined by the Contracting Officer, whenever such control is necessary to obtain the type of material required for Embankment Material.

Mixing of materials during the excavating process at the borrow area may be required.

2.1.1 Granular Fill

Granular Fill shall meet requirements for Satisfactory Material and shall contain not more than 12 percent by weight of material passing the No. 200 sieve.

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2.1.2 Random Fill

Random fill materials shall be of a character and quality satisfactory for the purpose intended, and meet the applicable material specifications for Satisfactory Materials.

2.1.3 Embankment Material

2.1.3.1 Select Impervious Fill

Select Impervious Fill shall consist of soils with CL, GC or SC classifications in accordance with ASTM D 2487, have 45 percent or more passing the No. 200 sieve, have a plasticity index (PI) between 12 and 30, have no particles greater than 3 inches, and are obtained from the designated borrow areas. Materials having 85 percent fines by weight that are smaller than 0.05 mm shall not be acceptable.

2.1.3.2 Impervious Fill

Impervious Fill shall consist of cohesive materials with 30 percent or more passing the No. 200 sieve, have a plasticity index (PI) between 3 and 35, and are obtained from the acceptable borrow sources. Materials having 85 percent fines by weight that are smaller than 0.05 mm shall not be acceptable.

2.1.3.3 POTENTIAL BORROW SOURCES LISTED

Impervious fill and select impervious fill may be available from the potential borrow sources listed, or at the option of the Contractor, may be furnished from Contractor designated sources, as accepted by the Contracting Officer.

Borrow Site #

Land Owner Township Range Section Description

Site 1 Site 2 Site 3 Site 4 Site 5

Koteski Peterson (Lower) Birkeland Olsen Ackerman

154N 153N 153N 153N 153N

65W 64W 63W 63W 63W

35,36 16,17 17,18

SE1/4, W1/2

NW1/2

NW 1/4

SW1/4, SE1/4

SW&NW 1/4, NE 1/4

2.1.4 Sand Drain and Filter Stone

Gradation of the material shall be determined in accordance with ASTM C 136.

All points on individual grading curves obtained from representative samples of filter material shall lie between the boundary limits as defined by smooth curves drawn through the tabulated grading limits plotted on a mechanical analysis diagram. The individual grading curves within these limits shall not exhibit abrupt changes in slope denoting skip grading, scalping of certain sizes or other irregularities which would be detrimental to the proper functioning of the sand drain.

2.1.4.1 Sand Drain

Sand drain shall meet all requirements for fine aggregate for concrete as specified in NDDOT Section NDDOT 816.01 except gradation shall be as specified herein. Sand drain shall consist of well graded sand and fine

SECTION 35 73 13 Page 10 W912ES-11-B-0005 gravel between the limits specified below:

SIEVE SIZE PERCENT BY WEIGHT PASSING

3/8-inch 100

No. 4 95-100

No. 16 45-80

No. 50 10-30

No. 100 0-10

No. 200 0-3 (as delivered)

0-5 (in place)

2.1.4.2 Filter Stone

Filter stone shall meet all requirements for permeable base aggregate as specified in NDDOT Section NDDOT 816.03 except gradation shall be as specified herein. Filter stone shall consist of medium-coarse sand and fine gravel between the limits specified below:

SIEVE SIZE PERCENT BY WEIGHT PASSING

1-inch 100

3/4-inch 95-100

1/2-inch 85-100

3/8-inch 60-90

No. 4 15-25

No. 8 2-10

No. 200 0-3

2.1.4.3 Sand Drain and Filter Stone Sources

Sand Drain and Filter Stone may be available from the potential borrow sources listed, or at the option of the Contractor, may be furnished from Contractor designated sources, as accepted by the Contracting Officer.

Source Name Source Location

Rollag Pit, Aggregate Industries

SE 1/4, Sec. 31, T138N, R43W, Clay County, MN

Grand Forks Pit, Strata Corporation

NE 1/4, Sec. 29, T150N, R52W Grand Forks County, ND

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Source Name Source Location

Riverdale Pit, Fisher Sand and Gravel

SW 1/4, Sec. 27, T146N, R84W, McLean County, ND

Carpenter Pit, Lyle Construction

NE 1/4 Sec. 10, T162N, R57W, Cavalier County, ND

2.1.5 Topsoil

Material suitable for topsoils obtained from stripping, required excavation, and offsite areas, is defined as: Natural, friable soil representative of productive, well-drained soils in the area, free of subsoil, stumps, rocks larger than one inch diameter, brush, weeds, toxic substances, and other material detrimental to plant growth. Where sufficient existing topsoil conforming to the material requirements is not available from on site stripping or excavation operations, provide borrow materials suitable for use as topsoil.

2.1.6 Granular Fill under Structures

Granular fill shall be a free draining well-graded mixture of stone fragments or gravel, coarse sand, and fine sand, Maximum size and gradation shall be meet all requirements for CL 3 or CL 5 base aggregate as specified in NDDOT Section NDDOT 816.03 except the maximum amount passing the No. 200 sieve shall not exceed 5 percent.

PART 3 EXECUTION

3.1 LINES AND GRADES

The Government reserves the right to increase or decrease the foundation widths or the embankment slopes or make such other changes in the embankment sections as may be deemed necessary to produce a safe structure. Increases in height of section, made to compensate for shrinkage or consolidation of the embankment material subsequent to the completion of the embankment, will not exceed five (5) percent of the height above the foundation indicated. The end slopes and side slopes of partial fill sections shall not be steeper than one vertical on four horizontal.

The Government reserves the right to direct the Contractor to increase or decrease the excavation elevation lines and grades as shown on the drawings in order to minimize the excavation work or to provide a foundation that will support construction equipment. The Contractor shall immediately notify the CO when marl, exposed during stripping or excavation operations, is determined to be unsatisfactory material.

3.2 CONDUCT OF WORK

Maintain and protect the Embankment in a satisfactory condition at all times until final completion and acceptance of all work under the contract. If in the opinion of the Contracting Officer the hauling equipment causes horizontal shears or slick sides, rutting, quaking, heaving, cracking or excessive deformation of the embankment, limit the type, load or travel speed of the hauling equipment on the embankment. Any approved embankment material which is lost in transit or rendered unsuitable after being placed in the embankment and before final acceptance of the work, shall be replaced in a satisfactory manner and no additional

SECTION 35 73 13 Page 12 W912ES-11-B-0005 payment will be made there for. Excavate and remove from the embankment any material which the Contracting Officer considers objectionable, dispose of such material, and refill the excavated area as directed, all at no cost to the Government. The Contractor may be required to remove, without additional payment, any embankment material placed outside of prescribed slope lines.

3.3 FROZEN MATERIALS

Embankment shall not be placed on a foundation which contains frozen material, or which has been subjected to freeze-thaw action. This prohibition encompasses all foundation types, including the natural ground, all prepared subgrades, whether in an excavation or on an embankment, and all layers of previously placed and compacted earth fill which become the foundations for successive layers of earthfill. Snow, ice, or frozen earth shall not be incorporated in the Embankment. All Embankment Material that freezes or has been subjected to freeze-thaw action during the construction work, or during periods of temporary shutdowns, such as, but not limited to, nights, holidays, weekends, or winter shutdowns or earthwork operations, shall be removed to a depth that is acceptable to the Contracting Officer and replaced. Alternatively, the Embankment Material shall be thawed, dried, reworked, and recompacted to the specified criteria before additional Embankment Material is placed. The Contracting Officer will determine when placement of Embankment Material shall cease due to cold weather.

3.4 CLASSIFICATION OF SOIL MATERIALS

Classification of soil materials shall be performed by the Contractor in accordance with ASTM D 2488. The Contracting Officer reserves the right to revise the Contractor classifications. In the case of disagreement, the Contracting Officer's classification will govern unless the soils are classified in accordance with ASTM D 2487. Not withstanding provisions of FAR 52.246-12 INSPECTION OF CONSTRUCTION, testing completed by the Contractor in conjunction with soil material classification will be considered incidental to the contract work.

3.5 STOCKPILES

Stockpiles shall be kept in a neat and well drained condition, giving due consideration to drainage at all times. The ground surface at stockpile locations shall be cleared, grubbed, and sealed. Embankment Material shall be protected from contamination which may destroy the quality and suitability for incorporation into the completed work. Stockpiled Embankment Material that becomes contaminated, frozen or too wet for use shall be removed at no additional cost to the Government.

3.6 UTILIZATION OF EXCAVATED MATERIALS

Material removed from excavations shall be incorporated in the work insofar as practicable. No excavated material that is satisfactory for use as fill shall be wasted without specific written authorization. Material authorized to be wasted shall be stored in designated areas approved for surplus material storage and disposed of offsite. No excavated material shall be disposed of in such a manner as to obstruct the flow of any stream, endanger a partly finished structure, impair the efficiency or appearance of any structure, or be detrimental to the completed work in any way.

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3.7 BORROW MATERIAL

Borrow material shall be selected to meet the requirements and conditions of the particular fill or embankment for which it is to be used. Borrow material shall be obtained from the borrow areas shown or from other approved sources, either private or within the limits of the project site, selected by the Contractor. Unless otherwise provided in the contract, the Contractor shall obtain from the owners the right to procure material, pay royalties and other charges involved, and bear the expense of developing the sources, including rights-of-way for hauling. Borrow material from approved sources on Government-controlled land may be obtained without payment of royalties. Unless specifically provided, no borrow shall be obtained within the limits of the project site without prior written approval. Necessary clearing, grubbing, and drainage of borrow pits and the disposal of debris thereon shall be considered related operations to the borrow excavation.

Any information provided by the Government or shown on borrow site maps is based on National Wetland Inventory information and is provided only for preliminary planning purposes.

3.7.1 Borrow Sites

3.7.1.1 USACE Potential Borrow Sites

Impervious core and select impervious core may be available from the potential borrow sources listed in paragraph 2.1.3.3.

3.7.1.2 Borrow Site Submittals

The Contractor's submitted borrow site plan and work plan shall provide the following information with respect to any borrow site areas proposed for use:

1. A map showing the delineated boundaries of wetlands.

2. Documentation of the methodology used to delineate the wetlands.

3. Qualifications of the individual that performed the wetland delineation. Any wetland boundaries not delineated by U.S Fish and Wildlife Service personnel for compliance with FWS easement requirements shall be delineated in accordance with the, "Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Great Plains Region." If the sites to be surveyed are within agricultural lands, particularly row cropped fields, the delineator shall use the annual crop slides flown by the Farm Services Administration and document "wet" signatures during periods of normal antecedent rainfall. The Manual is on the web site below:

http://www.usace.army.mil/cecw/pages/reg_supp.aspx

4. Excavation plan for the site and a description of the mitigation plan for any wetlands adversely affected.

5. Where proposed borrow sites have U.S. Fish and Wildlife Service (Service) easements on them, it is imperative to coordinate with the Service prior to developing an excavation plan (and any excavation) so that an on-site visit can be completed to identify protected wetland basins and their watersheds. 30 Days notice must be given to the

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Service so that the on-site visit can be completed in a timely manner commensurate with the construction schedule. The USFWS POCs are Jim Alfonso at (701)662-8611 ext. 327 or Paul Halko (701)662-8611 ext. 323.

3.7.1.3 Other Borrow Sites

If the proposed borrow site is not one of those listed as a potential borrow source under paragraph 2.1.3.3, the Contractor shall submit the information required under paragraph 3.7.1.1 and the additional following items:

If a cultural resources survey was performed for the proposed borrow site location, provide a summary of the persons that performed the work, title of report, date of report, and authors of the report.

Provide a summary of the results of the survey.

If a cultural resources survey was performed, the Contractor shall provide documentation of coordination of the survey report with the North Dakota SHPO. A copy of the concurrence letter from the SHPO will be considered sufficient to fulfill this submittal item.

If the proposed pit location has not been previously surveyed for cultural resources, the Contractor shall conduct a Phase I cultural resources survey (Class III inventory). The survey shall be performed by a professional archeologist. The survey report shall be submitted to the Government. The Government will coordinate the results of the cultural resources survey with the North Dakota SHPO.

If the pit is existing but the horizontal extents of the pit will be enlarged beyond the extents surveyed as part of a previous cultural resources survey, then the Contractor shall provide a cultural resources survey for the pit area that extends beyond the previous survey limits.

Note that no pit shall be used for the project unless SHPO coordination is completed and documented.

3.7.2 Excavation and Borrow Pits

Except as otherwise permitted, borrow pits and other excavation areas shall be excavated providing adequate drainage. Overburden and other spoil material shall be transported to designated spoil areas or otherwise disposed of, or used for special purposes. Borrow pits shall be neatly trimmed and drained after the excavation is completed. The Contractor shall ensure that excavation of any area, operation of borrow pits, or dumping of spoil material results in minimum detrimental effects on natural environmental conditions.

3.7.3 Utilization of Excavated Materials

Material removed from excavations shall be incorporated in the work insofar as practicable. No excavated material that is satisfactory for use as fill shall be wasted without specific written authorization. Material authorized to be wasted shall be stored in designated areas approved for surplus material storage and disposed of offsite. No excavated material shall be disposed of in such a manner as to obstruct the flow of any stream, endanger a partly finished structure, impair the efficiency or appearance of any structure, or be detrimental to the completed work in any way.

SECTION 35 73 13 Page 15 W912ES-11-B-0005

3.8 EXCAVATION

Excavation of every type, regardless of material encountered, within the grading limits of the project shall be performed to the lines and grades indicated. Excavation material suitable for use as fill shall be transported to and placed in fill areas within the limits of the work. All unsatisfactory material, including any soil which is disturbed by the Contractor's operations or softened due to exposure to the elements and water, and surplus material shall be disposed of in areas approved for off site disposal. Excavations carried below the depths indicated or determined by the Contracting Officer shall be refilled to the proper grade with Select Impervious Fill or Impervious Fill as indicated. During construction, excavation and fill shall be performed in a manner and sequence that will provide proper drainage at all times. Material required for fill or embankment in excess of that produced by excavation within the grading limits shall be excavated from the borrow areas indicated or from other approved areas selected by the Contractor as specified.

3.8.1 Excavation Advancement

The Contractor shall sequence operations such that required Existing Embankment excavation progresses along the Existing Embankment alignment no more than 500 lineal feet, per heading, in advance of Embankment construction to the elevation of the Existing Ground or higher. The intent of this restriction is to limit the lineal feet, along the Existing Embankment alignment, of flood barrier that is compromised due to Existing Embankment excavation.

Excavation of the existing embankment toe and removal of the existing sand drain shall be to the extent indicated on the drawings or otherwise required, but in no case deeper than the bottom of the existing sand drain.

Excavation of the existing embankment toe must be done after stripping, any required foundation excavation, and backfill of material to the existing ground.

3.8.2 Ditches, Gutters, and Channel Changes

Ditches, gutters, and channel changes shall be cut accurately to the cross sections and grades indicated. Gutters and ditches shall be finished in a manner that will result in effective drainage. All roots, stumps, rock, and foreign matter in the sides and bottom of ditches, gutters, and channel changes shall be trimmed and dressed or removed to conform to the slope, grade, and shape of the section indicated. Care shall be taken not to excavate ditches and gutters below the grades indicated. Excessive ditch and gutter excavation shall be backfilled to grade with properly placed and compacted material. All ditches and gutters excavated under this section shall be maintained until final acceptance of the work. Satisfactory material excavated from ditches and channel changes shall be placed in fill areas.

3.8.3 Inspection Trench

The inspection trench will be used to locate undesirable subsurface features. Any pipes, tiles, conduits, buried debris, or other unsatisfactory foundation materials encountered, such as sand or gravel, shall be removed from within the footprint of the levee or plugged as directed by the Contracting Officer. The Contractor shall notify the

SECTION 35 73 13 Page 16 W912ES-11-B-0005

Contracting Officer 48 hours prior to start of this work. Observations shall be recorded on the report forms attached to this specification, or on a Contractor's special purpose form for observing trench excavations if approved by the Contracting Officer.

a. Inspection Trench Excavation and Observation. An inspection trench will be excavated as shown on the plans. Immediately after excavating the trench, the Contractor shall inspect and record the soil and water conditions encountered and any other pertinent features. Soils on the base and side slopes shall be identified in accordance with ASTM D 2488.

In reaches where caving occurs, the Contractor shall either widen the trench, dewater to keep the trench stable, or assign a competent person to observe the excavation continuously in addition to the excavator operator. Excessive water seepage shall be removed to allow visual inspection. During construction of the inspection trench, the Contractor shall immediately notify the Contracting Officer in the event that soil conditions encountered differ significantly from those shown on the boring logs.

b. Inspection Trench Backfill. The Contracting Officer will observe the trench before backfilling, unless waived for trench stability reasons. All water and mud shall be removed from the trench before backfill is placed. The excavated material may be used for backfill only if it meets the material specified. All inspection trench backfill shall be placed in lifts and compacted as specified in

PARAGRAPH: COMPACTION.

c. Inspection Trench Location. The inspection trench shall generally be located close to the levee centerline. The inspection trench shall be continuous at all points, aligned with smooth curves, and free from abrupt changes in alignment. The Contracting Officer may direct the actual alignment of the inspection trench within the limits of the levee right of way to intercept suspect areas.

3.8.4 Marl Inspection Trench

Excavate and backfill an inspection trench to define the limits of Marl between the stations and at the depths indicated in the table below.

Marl Inspection Trench excavation must not exceed the limits shown for embankment stability.

3.8.4.1 Marl Inspection Trench Excavation and Observation

Excavate a 2 foot wide trench as shown on the drawings prior to stripping to define the limits of unsatisfactory marl. Inspection trench backfill shall not proceed until the Contracting Officer gives approval to backfill.

3.8.4.2 Marl Inspection Trench Backfill

Backfill the marl inspection trench with satisfactory excavated materials.

Place and compact the trench backfill in sufficient lifts and in such a manner that will insure that all excavated materials are replaced within the original trench limits. If the excavated material is unsatisfactory Marl and is unworkable, backfill the trench with impervious fill and compacted to that of the surrounding soils. Haul unsatisfactory material to offsite disposal.

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3.8.4.3 Marl Inspection Trench Location

The marl inspection trench shall be located at an approximate equal distance between the existing embankment toe and the new embankment toe.

3.9 STRUCTURES

3.9.1 General

Excavation shall conform to the dimensions and elevations indicated for each building, structure, and footing including necessary oversizing.

Building excavation shall include trenching for utility and foundation drainage systems to a point 5 feet beyond the building line of each building and structure and all work incidental thereto. Excavations shall extend a sufficient distance from walls and footings to allow for placing and removal of forms.

3.9.1.1 Granular fill under Structures

Place 2 feet of granular fill under the foundation slabs for the Lakewood pump station and retaining wall, Hwy 20 pump station and drop inlet structure. The granular fill shall be placed to a minimum of 1 foot outside the foundation base slabs. The granular fill material and placement shall be considered incidental to and included in the lump sum cost for the structure.

3.9.2 Over Depth Excavation

Excavations below indicated depths will not be permitted except to remove unsatisfactory material. Material removed below the depths indicated or beyond the tolerances specified shall be replaced with properly placed and compacted fill at no additional cost to the Government, except that concrete footings may be increased in thickness to the bottom of the over depth excavation if approved by the Contracting Officer.

3.9.3 Drainage

Surface water shall be directed away from excavation and construction sites so as to prevent erosion and undermining of foundations. Diversion ditches, dikes and grading shall be provided and maintained as necessary during construction. Excavated slopes and backfill surfaces shall be protected to prevent erosion and sloughing. Excavation shall be performed so that the site and the area immediately surrounding the site and affecting operations at the site shall be continually and effectively drained.

3.9.3.1 Dewatering

Groundwater flowing into excavations shall be controlled to prevent sloughing of excavation slopes and walls, boils, uplift and heave in the excavation and to eliminate interference with orderly progress of construction. French drains, sumps, ditches or trenches will not be permitted within 3 feet of the foundation of any structure, except with specific written approval, and after specific contractual provisions for restoration of the foundation area have been made. Control measures shall be taken by the time the excavation reaches the water level in order to maintain the integrity of the in situ material. While the excavation is open, the water level shall be maintained continuously, at least 2 feet below the working level.

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3.9.4 Foundation Compaction

For structures with granular subgrades, the granular material shall be surface compacted in layers per the table: PLACEMENT & COMPACTION REQUIREMENTS FOR FILL, at the end of this section, using a vibratory compactor and compacted to at least 100 Percent of the Standard Proctor density

3.9.5 Backfilling

Structure excavations shall be backfilled with satisfactory material unless indicated otherwise on the plans. Backfilling shall not begin until construction below finish grade has been approved, underground utilities systems have been inspected, tested and approved; concrete forms have been removed and the excavation cleaned of frost, trash and debris. Backfill shall not be placed against foundation walls prior to 7 days after completion of the walls. As far as practicable, backfill shall be brought up evenly on each side of the wall. Trenches not immediately backfilled to grade shall be sloped to drain if practicable. Heavy equipment for spreading and compacting backfill shall not be operated closer to a foundation or other underground structural element than a distance equal to the height of backfill above the top of footing; the area remaining shall be compacted with power driven hand tampers suitable for the material being compacted. See Table PLACEMENT & COMPACTION REQUIREMENTS FOR FILL, at the end of this Section.

3.10 STRIPPING

Where indicated or directed, strip material to the depth indicated on the drawings and stockpile separately from other excavated material. Stripped material not suitable for use as topsoil shall be disposed off site.

3.10.1 Stripped Material Suitable For Use As Topsoil

Stripped material suitable for use as topsoil shall be transported and deposited on areas already graded and prepared for topsoil, or stockpiled in locations convenient to areas that are to receive application of the topsoil later. Stripped material suitable for use as topsoil shall be protected and kept separate from other excavated materials, brush, litter, objectionable weeds, roots, stones larger than 1 inch in diameter, and other materials that would interfere with planting and maintenance operations until needed. Remove from the site any surplus of stripped material suitable for use as topsoil.

3.11 SUBGRADE PREPARATION

All areas upon which Embankment Material is to be placed shall be stripped before the Embankment Material is placed. Embankment Material shall not be placed on surfaces that are muddy, frozen, contain frost, or where unsatisfactory material remains in or under the fill. For cohesionless soils, the subgrade surface shall be compacted to at least 100 Percent of the Standard Proctor density. For cohesive soils, the subgrade shall be proof rolled with rubber tired equipment and any soft areas shall be brought to the Contracting Officer's attention. Sloped ground surfaces steeper than one vertical to four horizontal on which fill is to be placed shall be stepped such that the Embankment Material will bond with the existing surface.

Do not disturb the finished subgrade by traffic or other operation. Do not

SECTION 35 73 13 Page 19 W912ES-11-B-0005 permit the storage or stockpiling of materials on the finished subgrade.

Sides of stump holes, test pits, and other similar cavities or depressions shall be broken down, where so directed, so as to flatten out the slopes, and the sides of the cut or hole shall be scarified to provide bond between the foundation material and the fill.

The slopes and bottom of excavations shall be scarified, as directed.

Unless otherwise directed, each excavation or depression shall be filled with Select Impervious Fill. Select Impervious Fill shall be placed in layers, moistened, and compacted in accordance with the applicable provisions of paragraphs PLACEMENT, MOISTURE CONTROL, and COMPACTION.

Select Impervious Fill which cannot be compacted by roller equipment because of inadequate clearances shall be spread in 4-inch layers and compacted with power tampers to an extent equal to that of the contiguous embankment fill material.

After filling of depressions and immediately prior to placement of compacted fill in any section of the embankment, the foundation of such section shall be loosened thoroughly by scarifying, plowing, discing or harrowing to a minimum depth of 6 inches, and the moisture content shall be adjusted to the amount specified in paragraph MOISTURE CONTROL for the appropriate type of material

After removal of roots or other debris turned up in the process of loosening, the entire surface of the embankment foundation area shall be compacted by 12 complete coverages for fine-grained soils, or to a depth of 6 inches for coarse-grained soils, by the compaction equipment as specified for the appropriate type of foundation soil.

3.11.1 Subgrade Correction

Compacted subgrades that are disturbed by the Contractor's operations or adverse weather shall be scarified and compacted as specified herein to the required density prior to further construction thereon. Subgrades not meeting the specifications for finish, material type and density at the time of surface material placement shall be corrected at the Contractor's expense. Cohesive embankments and subgrades shall be kept crowned or sloped for drainage. Newly graded areas shall be protected from traffic and erosion. Any settlement or washing away that may occur from any cause shall be repaired. Ditches and drains along subgrade shall be maintained to provide effective drainage. All work shall implement best management practices for erosion control.

3.11.2 Marl Subgrade Correction

When unsatisfactory marl is encountered, corrective action must be taken in order to meet compaction requirements of embankment fill being placed on the subgrade. Corrective actions are listed below and must be approved by the CO prior to embankment fill placement.

Option 1. If the marl is unsatisfactory material and can be completely excavated without exceeding the maximum allowable excavation depths as defined in the Marl Inspection Trench Limits table, then excavate the unsatisfactory marl and backfill as directed in this section.

Option 2. If the marl is unsatisfactory material and cannot be completely excavated without exceeding the allowable excavation depths as defined in the Marl Inspection Trench Limits table, geotextile

SECTION 35 73 13 Page 20 W912ES-11-B-0005 fabric in accordance with the requirements for geotextile fabric in SECTION 35 31 19.00 13, shall be placed on the subgrade surface after completion of stripping. Granular fill shall be placed on top of the geotextile fabric, in 8-inch layers, or in the minimum layer thickness needed to support construction equipment and to provide a workable surface for embankment fill placement and compaction.

3.11.3 Marl Subgrade Preservation

The Contractor shall use reasonable means and methods, to preserve satisfactory marl subgrades from becoming unsatisfactory marl subgrades due to subgrade disturbance from the operation of Contractor equipment, in order to minimize marl subgrade correction.

3.12 PRAIRIE POTHOLES

Prairie potholes shall be:

Stripped to the depths indicated on the drawings, Filled with the material as indicated on the drawings and material shall be compacted to the same level as the surrounding undisturbed ground, and Topsoiled and seeded as indicated on the drawings and in accordance with the specification.

3.13 EMBANKMENT MATERIAL PLACEMENT

3.13.1 Inspection and Approval

No Embankment Material shall be placed on any part of the embankment foundation until such areas have been inspected and approved. The gradation and distribution of materials throughout the compacted earth fill section of the dam shall be such that the embankment will be free from lenses, pockets, streaks, and layers of material differing substantially in texture or gradation from surrounding material of the same class.

3.13.2 Rate of Placement

Unless otherwise directed, the embankment within each increment of length shall be maintained at approximately the same level regardless of the number of types of materials being placed, except that the vertical sand drain shall be placed with sufficient lag to prevent mixture with the embankment Select Impervious Fill. The rate of embankment placement within each increment shall be the maximum that can be practically achieved within the working space available and without interruption or delays unless approved by the Contracting Officer. Work below existing lake levels shall continue for the number of hours per day and number of days per week required to prevent freezing of newly placed embankment materials during cold weather construction or to address other weather related conditions that could cause delay of the work. See Action and Response Plan for required emergency provisions to stabilize deteriorating conditions of the existing embankment that threaten release of the impounded water.

3.13.3 Spreading

After dumping, the materials shall be spread by bulldozers or other approved means in approximately horizontal layers over the entire fill areas. Unless otherwise directed, the thickness of these layers before compaction with tamping type rollers shall not be more than 9 inches (6

SECTION 35 73 13 Page 21 W912ES-11-B-0005 inches if compacted by hand tamper) for Select Impervious Fill and Impervious Fill. Unless otherwise directed, the thickness of layers before compaction with rubber-tired rollers shall not be more than 12 inches for Select Impervious Fill and Impervious Fill.