31 23 00.00 20_amnd0005.pdf

FY22 MCAF PROJECT PAF180400 AIRCRAFT MAINT. SUPPORT FACILITY 1665828

RAAF, TINDAL

SECTION 31 23 00.00 20

EXCAVATION AND FILL

02/11, CHG 2: 08/15

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 in the text by the basic designation only.

NORTHERN TERRITORY GOVERNMENT (NTG)

NTMTM NT Materials Testing Manual

STANDARDS AUSTRALIA (AS)

AS 1289 Methods of testing soils for engineering purposes

U.S. ENVIRONMENTAL PROTECTION AGENCY (EPA)

EPA SW-846.3-3 (1999, Third Edition, Update III-A) Test Methods for Evaluating Solid Waste:

Physical/Chemical Methods

1.2 DEFINITIONS

1.2.1 Carriageway

That portion of a road for the use of vehicles including shoulders and auxiliary lanes.

1.2.2 Formation

The surface of finished earthworks on which a road pavement is constructed. It includes the earthworks (cut and fill), subgrade and the general shaping of the drainage. The formation width is therefore the distance of cut or fill including table drain(s), out to the points of any batters.

1.2.3 Offlet Drain

Also described as a Table Drain Offlet. Provides relief at regular intervals of run off concentration in Table Drain. Drains water from Table Drain away from formation for dispersal into catchments. Also extends under footpaths, kerb and gutter, and surface structures.

Includes the associated drain block to direct flow from the table drain into the offlet drain.

1.2.4 Subgrade

Top 150 mm of material below subgrade surface. Also known as subgrade layer.

1.2.5 Subgrade Surface

The prepared surface immediately beneath the pavement and shoulder layers.

SECTION 31 23 00.00 20 Page 1 Amendment 0005- 27 Jan 2025

1.2.6 Surface Formation

A road formation constructed from material generally cut from the table drains.

1.2.7 Unpaved Areas

Those areas within the road reserve boundary which are not part of the road pavement, including any medians not paved, but excluding footpaths and vehicle access strips.

1.2.8 Unsuitable Material

Any material that does not conform to the properties specified for the replacement materials to be used. If properties of the replacement materials to be used are not specified, then UNSUITABLE MATERIALS are materials which do not conform to the properties specified for standard fill.

1.2.9 Hard Materials

Weathered rock, dense consolidated calcareous deposits, cemented sand, conglomerate materials, concrete and asphaltic concrete, hard cobbles, or hard boulders 2 cubic meters or less in volume which are not included in the definition of "rock" with stones greater than 750 mm in any dimension. The materials usually require the use of heavy excavation equipment with ripper teeth, backhoe-mounted pneumatic hole punchers, or jack hammers for removal.

1.2.10 Rock

Solid homogeneous interlocking crystalline material with firmly cemented, laminated, or foliated masses or conglomerate deposits, including Tindal limestone which cannot be removed without drilling and the use of expansion jacks or feather wedges, or the use of backhoe-mounted pneumatic hole punchers or rock breakers; also large boulders, buried masonry, or concrete other than pavement exceeding 0.75 cubic meter in volume. Removal of hard material will not be considered rock excavation because of intermittent drilling that is performed merely to increase production.

1.2.11 Pile Supported Structure

As used herein, a structure where both the foundation and floor slab are pile supported.

1.3 SUBMITTALS

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

submittals not having a "G" designation are for Contractor Quality Control approval. Submit the following in accordance with Section

01 33 00 SUBMITTAL PROCEDURES:

SD-01 Preconstruction Submittals

Shoring and Sheeting Plan

Dewatering work plan

Submit 15 days prior to starting work.

SD-03 Product Data

Filter Fabric ; G

SECTION 31 23 00.00 20 Page 2

Bedding Material ; G

Buried Warning And Identification Tape ; G

SD-06 Test Reports

Borrow Site Testing ; G

Fill and backfill test

Select Granular Material Test; G

Density Tests ; G

Field Density ; G

Copies of all laboratory and field test reports within 24 hours of the completion of the test.

1.4 DELIVERY, STORAGE, AND HANDLING

Perform in a manner to prevent contamination or segregation of materials.

1.5 CRITERIA FOR BIDDING

Base bids on the following criteria:

a. Surface elevations are as indicated.

b. Pipes or other artificial obstructions, except those indicated, will not be encountered.

c. Ground water elevations indicated by the boring log were those existing at the time subsurface investigations were made and do not necessarily represent ground water elevation at the time of construction. It is known that groundwater levels fluctuate onsite, especially after periods of heavy wet season rainfall.

Investigations were conducted at the end of the Northern Territory dry season, prior to any wet season rainfall.

The natural soils have a high propensity to significantly soften with increases in moisture content. Include a provisional sum for cost of stripping top 300mm of material and replacing with drier, imported filling.

d. Material character is indicated by the boring logs.

e. Borrow material and suitable backfill in the quantities required is available at the project site.

f. Blasting will not be permitted. Remove material in an approved manner.

g. All material on site (PFAS Category 3 or 4 material) should be excavated, handled, reused and disposed of as per the DoD PFAS Construction Management Framework (2019), DCMM Annex C Soil Stockpiles and Reuse of Excavated Material (2018) and the approval of the RAAF Base Tindal Environment and Sustainability Manager (ESM) / Assistant Director Environment Sustainability (ADES), Base Services and PFAS Investigation and Management Branch (PFAS IMB).

h. Excavation in areas with hard materials and rock shall be expected to be slow.

SECTION 31 23 00.00 20 Page 3

1.6 REQUIREMENTS FOR OFF SITE SOIL

Soils brought in from off site for use as backfill shall be tested for PFAS, petroleum hydrocarbons, PAH, metals, BTEX, PCBs and HW characteristics (including toxicity, ignitability, corrosivity, and reactivity). Backfill shall not contain concentrations of these analytes above the appropriate Australian Government and/or EPA NSW criteria, and shall pass the tests for HW characteristics. Determine petroleum hydrocarbon concentrations by using appropriate Australian Government protocols. Determine BTEX concentrations by using EPA SW-846.3-3 Method 5035/8260B or equivalent if approved by Contract Administrator. Perform complete TCLP in accordance with EPA SW-846.3-3 Method 1311 or equivalent if approved by Contract Administrator. .

Perform HW characteristic tests for ignitability, corrosivity, and reactivity in accordance with accepted standard methods. Perform PCB testing in accordance with accepted standard methods for sampling and analysis of bulk solid samples. Provide borrow site testing for petroleum hydrocarbons, PFAS, and BTEX from a grab sample of material from the area most likely to be contaminated at the borrow site (as indicated by visual or olfactory evidence), with at least one test from each borrow site. For each borrow site, provide borrow site testing for HW characteristics from a composite sample of material, collected in accordance with standard soil sampling techniques. Do not bring material onsite until tests results have been received and approved by the Contracting Officer.

1.7 QUALITY ASSURANCE

1.7.1 Dewatering Work Plan

Submit procedures for accomplishing dewatering work.

1.7.2 Utilities

Movement of construction machinery and equipment over pipes and utilities during construction shall be at the Contractor's risk.

Perform work adjacent to non-Government utilities as indicated in accordance with procedures outlined by utility company. Excavation made with power-driven equipment is not permitted within 600 mm of known Government-owned utility or subsurface construction. For work immediately adjacent to or for excavations exposing a utility or other buried obstruction, excavate by hand. Start hand excavation on each side of the indicated obstruction and continue until the obstruction is uncovered or until clearance for the new grade is assured. Support uncovered lines or other existing work affected by the contract excavation until approval for backfill is granted by the Contracting Officer. Report damage to utility lines or subsurface construction immediately to the Contracting Officer.

PART 2 PRODUCTS

2.1 SOIL MATERIALS

2.1.1 General Fill

AUse the best locally available material. Use fill material, whether cut or borrow, that is free of organic matter and has a minimum soaked CBR at 95 percent MMDD of 20 percent, to AS 1289 , and a plasticity index between 2 percent and 15 percent.

Reuse of existing Category 4 PFAS material stockpiles on RAAF Base Tindal may be employed as general fill to within 0.5m of the finished floor level where practicable and where fill meets the minimum

SECTION 31 23 00.00 20 Page 4 requirements. Material must also have a maximum particle size of 75mm and fines content of less than 25 percent.

2.1.2 Select Fill

Select fill shall be comprised of gravel, decomposed rock or broken rock, free from organic matter and lumps of clay. Any new filling shall comprise a well graded granular soil with a maximum particle size of 75mm, placed in layers of 300mm maximum loose thickness with each layer compacted to at least 95 percent of the modified maximum dry density (MMDD) and within 2 percent of the optimum moisture Content for modified compaction.

Conform to the following:

Table - Grading - Select fill

AS SIEVE (mm) PERCENT PASSING (DRY WEIGHT)

75.00 100

9.50 30-100

2.36 15-65

0.07 5-25

Table - Select Fill Properties

CBR, 4 day soaked at 95 percent MMDD to

AS 1289 :

30 minimum

Plasticity Index 2-15 percent maximum

Linear Shrinkage 2-6 percent

For within 0.8 m of building footprints, exposed subgrade soils should then be compacted to 98 percent relative to standard compaction at a moisture content within 1.5 percent of the optimum moisture content. A final test roll accompanied by careful visual inspection by an experienced geotechnical professional shall be undertaken to allow detection of any areas requiring removal or further Compaction.

2.1.3 Unsatisfactory Materials

Materials which do not comply with the requirements for satisfactory materials. Unsatisfactory materials also include man-made fills, trash, refuse, or backfills from previous construction. Unsatisfactory material also includes material classified as satisfactory which contains root and other organic matter, and stones larger than 30. The Contracting Officer shall be notified of any contaminated materials.

2.1.3.1 2.1.3.1 Unsuitable Material Below Subgrade Surface other than Rock

Excavate subgrade material which does not conform to the properties of standard fill as specified. Dry out material with excessive moisture content to achieve a moisture content which permits specified compaction.

Replace excavated material with standard fill compacted to 95 percent relative compaction. Angular or broken rock, free from organic matter and

SECTION 31 23 00.00 20 Page 5 lumps of clay, complying with the Table - Grading - Suitable Fill Material Properties for Floodways.

Table - Grading - Suitable Fill Material Properties for Floodways

Maximun Size: 100 mm

Plasticity Index: 10 maximum.

Linear Shrinkage: 5.0 maximum

AS Sieve (mm) Percentage Passing

75.00 40-100

19.0 15-50

2.36 0-25

2.1.3.2 Unsuitable Material

Remove unsuitable foundation material as directed before the fill is placed. Replace excavated material with standard fill compacted to 95 percent relative compaction.

2.1.4 Common Fill

Approved, unclassified soil material with the characteristics required to compact to the soil density specified for the intended location.

2.1.5 Backfill and Fill Material

Backfill the excavation up to natural surface level with excavated material or select fill. The excavated material may be used for backfill provided it is free of wood, other organic and other extraneous or deleterious material. Mix to a homogeneous material before compacting.

Place in horizontal layers not exceeding 150 mm compacted thickness.

Compact to the density ratio specified in the Table - Dry Density Ratios for Conformance.

Table - Dry Density Ratios for Conformance

Works Components A Mean Dry Density Ratio

(R) percent ("n" is 3 to 5)

B Characteristic Mean Dry Density Ratio (Rc) percent ("n" is 6 or gre ater)

Natural surface to subgrade, fill, batters, table drain blocks, fill for water course, unpaved areas

95.0 or greater

94.9 or less

94.0 or greater Conformance

94.9 or less 93.9 or less Non-Conformance

SECTION 31 23 00.00 20 Page 6

Table - Dry Density Ratios for Conformance

Subgrade, shoulder sub base, unsealed pavement base, shoulder base, select fill, levees, structures and culverts in fill, bridge foundation backfill, br idge abutment fill

95.0 or greater 94.0 or greater Conformance

94.9 or less 93.9 or less Non-Conformance

Sealed pavement basecourse

100.0 or greater 99.0 or greater Conformance

99.9 or less 99.9 or less Non-Conformance

Sealed pavement sub-base, Stabilised and modified basecourse, Subgrade treatment for Reconstruction and Rehabilitation of Existing Pavements clause in

PAVEMENTS AND

SHOULDERS, or as dire cted by Superintendent

98.0 or greater 97.0 or greater Conformance

97.9 or less 96.9 or less Non-Conformance

Contractor to backfill all pavement layer test excavations with the material and density ratio specified for that layer, treated as follows:

Base and sub-base layers stabilised with 3 percent cement.

Other layers may be unstabilised.

2.1.6 Select Granular Material

Select granular material shall consist of materials in which the maximum particle size shall be 75 mm. and the fines content is not less than 25 percent. Fill should be placed in layers of 300mm maximum loose thickness with each layer compacted to at least 95 percent of the modified maximum dry density (MMDD) and within 1.5 percent of the optimum moisture Content for modified compaction.

2.2 UTILITY BEDDING MATERIAL

Except as specified otherwise in the individual piping section, provide bedding for buried piping in accordance with Standard Specification for Roadworks NTG (V 4.1) NTMTM NT.

2.3 BORROW

Obtain borrow materials required in excess of those furnished from excavations from sources outside of Government property.

SECTION 31 23 00.00 20 Page 7

2.4 MATERIAL FOR RIP-RAP

Bedding material, filter fabric and rock.

2.4.1 Bedding Material

Consisting of sand, gravel, or crushed rock, well graded, or poorly graded with a maximum particle size of 50 mm. Material shall be composed of tough, durable particles. Fines passing the 75 micrometers standard sieve shall have a plasticity index less than six.

2.4.2 Rock

The supply and installation of mattresses protection and scour control rock shall be in accordance with Clause 13.10 of the NT Department of Infrastructure - 2019 Standard Specification for Roadworks NTMTM NT.

Mattress protection shall be installed in the locations shown on the drawings. Geotextile fabric shall be Bidim A44 (or similar approved) and employed under all scour control rock.

2.5 BURIED WARNING AND IDENTIFICATION TAPE

Polyethylene plastic and metallic core or metallic-faced, acid- and alkali-resistant, polyethylene plastic warning tape manufactured specifically for warning and identification of buried utility lines.

Provide tape on rolls, 75 mm minimum width, color coded as specified below for the intended utility with warning and identification imprinted in bold black letters continuously over the entire tape length.

Warning and identification to read, "CAUTION, BURIED (intended service) LINE BELOW" or similar wording. Color and printing shall be permanent, unaffected by moisture or soil.

Purple Not Potable, Reclaimed Water, Irrigation and Slurry lines

2.5.1 Warning Tape for Metallic Piping

Acid and alkali-resistant polyethylene plastic tape conforming to the width, color, and printing requirements specified above. Minimum thickness of tape shall be 0.08 mm. Tape shall have a minimum strength of 10.3 MPa lengthwise, and 8.6 MPa crosswise, with a maximum 350 percent elongation.

2.5.2 Detectable Warning Tape for Non-Metallic Piping

Polyethylene plastic tape conforming to the width, color, and printing requirements specified above. Minimum thickness of the tape shall be

0.10 mm. Tape shall have a minimum strength of 10.3 MPa lengthwise and

8.6 MPa crosswise. Tape shall be manufactured with integral wires, foil backing, or other means of enabling detection by a metal detector when tape is buried up to 920 mm deep. Encase metallic element of the tape in a protective jacket or provide with other means of corrosion protection.

2.6 DETECTION WIRE FOR NON-METALLIC PIPING

Detection wire shall be insulated single strand, solid copper with a minimum of 12 AWG.

SECTION 31 23 00.00 20 Page 8

PART 3 EXECUTION

3.1 PROTECTION

3.1.1 Shoring and Sheeting

Provide shoring bracing, cribbing, trench boxes, underpinning and sheeting to protect workmen, utilities, structures, pavements, slabs and to perform work in a safe environment where indicated. Include provisions in the shoring and sheeting plan that will accomplish the following:

a. Prevent undermining of pavements, foundations and slabs.

b. Prevent slippage or movement in banks or slopes adjacent to the excavation.

3.1.2 Drainage and Dewatering

Provide for the collection and disposal of surface and subsurface water encountered during construction.

3.1.2.1 Drainage

So that construction operations progress successfully, completely drain construction site during periods of construction to keep soil materials sufficiently dry. The Contractor shall establish/construct storm drainage features (ponds/basins) at the earliest stages of site development, and throughout construction grade the construction area to provide positive surface water runoff away from the construction activity and/or provide temporary ditches, dikes, swales, and other drainage features and equipment as required to maintain dry soils, prevent erosion and undermining of foundations. When unsuitable working platforms for equipment operation and unsuitable soil support for subsequent construction features develop, remove unsuitable material and provide new soil material as specified herein. It is the responsibility of the Contractor to assess the soil and ground water conditions presented by the plans and specifications and to employ necessary measures to permit construction to proceed. Excavated slopes and backfill surfaces shall be protected to prevent erosion and sloughing.

Excavation shall be performed so that the site, the area immediately surrounding the site, and the area affecting operations at the site shall be continually and effectively drained.

3.1.2.2 Dewatering

Groundwater flowing toward or 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 0.9 m 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. AA 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 m1 below the working level.

Operate dewatering system continuously until construction work below existing water levels is complete. Submit performance records weekly.

Measure and record performance of dewatering system at same time each day by use of observation wells or piezometers installed in conjunction with the dewatering system. Relieve hydrostatic head in previous zones below subgrade elevation in layered soils to prevent uplift.

SECTION 31 23 00.00 20 Page 9

3.1.3 Underground Utilities

Location of the existing utilities indicated is approximate. For utilities not scheduled for demolition, the Contractor shall physically verify the location and elevation of the existing utilities indicated prior to starting construction. The Contractor shall contact the utility owner for assistance in locating existing utilities within the work area. The Contractor shall scan the construction site with electromagnetic and sonic equipment and mark the surface of the ground where existing underground utilities are discovered. Should invert levels or location of any service connection points differ to that indicated on the drawings then the supervising engineer shall be notified immediately.

The alignment and level of existing services shown on this drawing has been compiled from an IFC drawing set for the neighboring fuel farm and LDBO facility, and is indicative only. Prior to commencing construction or ordering any materials the contractor is to confirm the alignment and level of all services affected by the proposed works.

3.1.4 Machinery and Equipment

Movement of construction machinery and equipment over pipes during construction shall be at the Contractor's risk. Repair, or remove and provide new pipe for existing or newly installed pipe that has been displaced or damaged.

3.2 SURFACE PREPARATION

3.2.1 Clearing and Grubbing

Performing clearing and grubbing in accordance with Section 31 11 00

CLEARING AND GRUBBING

3.2.2 Stripping

Strip suitable soil from the site where excavation or grading is indicated and stockpile separately from other excavated material.

Material unsuitable for use as topsoil shall be stockpiled and used for backfilling. Locate topsoil so that the material can be used readily for the finished grading. Where sufficient existing topsoil conforming to the material requirements is not available on site, provide borrow materials suitable for use as topsoil. Protect topsoil and keep in segregated piles until needed.

All material on site (Category 3 and 4 PFAS material) to be excavated, handled, reused and disposed of as per the DoD PFAS Construction Management Framework (2019), Annex C Soil Stockpiles and Reuse of Excavated Material (2018) and the approval of the RAAF Base Tindal Environment and Sustainability Manager (ESM) / Assistant Director Environment Sustainability (ADES), Base Services and PFAS Investigation and Management Branch (PFAS IMB).

3.2.3 Unsuitable Material

Remove vegetation, debris, decayed vegetable matter, sod, mulch, and rubbish underneath paved areas or concrete slabs.

3.3 EXCAVATION

Excavate to contours, elevation, and dimensions indicated. Reuse excavated materials that meet the specified requirements for the

SECTION 31 23 00.00 20 Page 10 material type required at the intended location. Keep excavations free from water. Excavate soil disturbed or weakened by Contractor's operations, soils softened or made unsuitable for subsequent construction due to exposure to weather. Excavations below indicated depths will not be permitted except to remove unsatisfactory material.

3.3.1 Structures With Spread Footings

Ensure that footing subgrades have been inspected and approved by the Contracting Officer prior to concrete placement. Fill over excavations with concrete during foundation placement.

3.3.2 Pipe Trenches

Excavate to the dimension indicated. Grade bottom of trenches to provide uniform support for each section of pipe after pipe bedding placement. Tamp if necessary to provide a firm pipe bed. Recesses shall be excavated to accommodate bells and joints so that pipe will be uniformly supported for the entire length. Rock, where encountered, shall be excavated to a depth of at least 150 mm below the bottom of the pipe.

3.3.3 Hard Material and Rock Excavation

Roughen level surfaces and cut sloped surfaces into benches for bond with concrete. Protect shale from conditions causing decomposition along joints or cleavage planes and other types of erosion. Removal of hard material and rock beyond lines and grades indicated will not be grounds for a claim for additional payment unless previously authorized by the Contracting Officer. Excavation of the material claimed as rock shall not be performed until the material has been cross sectioned by the Contractor and approved by the Contracting Officer. Common excavation shall consist of all excavation not classified as rock excavation.

3.3.4 Excavated Materials

Satisfactory excavated material required for fill or backfill shall be placed in the proper section of the permanent work required or shall be separately stockpiled if it cannot be readily placed. Satisfactory material in excess of that required for the permanent work and all unsatisfactory material shall be disposed of as specified in Paragraph

"DISPOSITION OF SURPLUS MATERIAL."

3.3.5 Final Grade of Surfaces to Support Concrete

Excavation to final grade shall not be made until just before concrete is to be placed. Only excavation methods that will leave the foundation rock in a solid and unshattered condition shall be used. Approximately level surfaces shall be roughened, and sloped surfaces shall be cut as indicated into rough steps or benches to provide a satisfactory bond.

Shales shall be protected from slaking and all surfaces shall be protected from erosion resulting from ponding or flow of water.

3.4 SUBGRADE PREPARATION

Trim, prepare, and maintain, subgrade surface to the required tolerances specified, free of depressions, cracking, laminations, organic inclusions, and other defects. Surface to be formed and maintained to be free draining, and suitable for proof rolling. Maintain and repair any damage to the prepared surface prior to placing further material.

Unsatisfactory material in surfaces to receive fill or in excavated areas shall be removed and replaced with satisfactory materials as

SECTION 31 23 00.00 20 Page 11 directed by the Contracting Officer. The surface shall be scarified to a depth of 150 mm before the fill is started. Sloped surfaces steeper than 1 vertical to 4 horizontal shall be plowed, stepped, benched, or broken up so that the fill material will bond with the existing material. When subgrades are less than the specified density, the ground surface shall be broken up to a minimum depth of 150 mm, pulverized, and compacted to the specified density. When the subgrade is part fill and part excavation or natural ground, the excavated or natural ground portion shall be scarified to a depth of 300 mm and compacted as specified for the adjacent fill. Material shall not be placed on surfaces that are muddy, frozen, or contain frost. Compaction shall be accomplished by sheepsfoot rollers, pneumatic-tired rollers, steel-wheeled rollers, or other approved equipment well suited to the soil being compacted. Minimum subgrade density shall be as specified herein.

For pavement subgrade, the exposed natural soils shall be tyned and moisture conditioned to approximate optimum moisture content for modified compaction over a depth of at least 300mm, then compacted to 95 percent relative to modified compaction at a moisture content within 1.5 percent of the optimum moisture content.

The subgrade soils should not be left exposed and allowed to dry, shrink and crack.

3.4.1 Proof Rolling

Proof rolling shall be done on an exposed subgrade free of surface water (wet conditions resulting from rainfall) which would promote degradation of an otherwise acceptable subgrade. Following re-compaction of the subgrade soils, the surface must be test rolled using a minimum 12 tonne deadweight roller, or an equivalent weight fully laden water cart, or similar.

Subgrade is deemed acceptable if it shows negligible (maximum 3mm) deflection.

Any wet, soft or weak areas identified during test rolling shall be removed and replaced with compacted filling.

3.5 SUBGRADE FILTER FABRIC

Place synthetic fiber filter fabric as indicated directly on prepared subgrade free of vegetation, stumps, rocks larger than 50 mm diameter and other debris which may puncture or otherwise damage the fabric.

Repair damaged fabric by placing an additional layer of fabric to cover the damaged area a minimum of 0.9 m overlap in all directions. Overlap fabric at joints a minimum of 0.9 m. Obtain approval of filter fabric installation before placing fill or backfill. Place fill or backfill on fabric in the direction of overlaps and compact as specified herein.

Follow manufacturer's recommended installation procedures.

3.6 FILLING AND BACKFILLING

Fill and backfill to contours, elevations, and dimensions indicated.

Compact each lift before placing overlaying lift.

3.6.1 Earthwork Pavements

For pavements, filling to raise the design subgrade level of the pavement footprint shall comprise of a well graded granular soil with a maximum particle size of not more than 75mm and a fines content of less than 25 percent.

SECTION 31 23 00.00 20 Page 12

Filling must be placed in layers of 300mm maximum loose thickness and compacted to the Nominated compaction to at least 95 percent of modified maximum dry density (mmdd) and within 1.5 percent of the optimum moisture content.

Placement of filling within pavement footprints shall be subject to level 2 geotechnical inspections and testing as per the requirements of

AS 3798-2007.

Refer NTG standard specification (v 4.1 - november 2019) for roadworks NTMTM NT, pavements and shoulders for pavement material properties, placement and testing requirements.

3.6.2 Earthwork Building Footprint

For building footprint, select fill shall be comprised of gravel, decomposed rock or broken rock, free from organic matter and lumps of clay. Any new filling shall comprise a well graded granular soil with a maximum particle size of 75mm, placed in layers of 300mm maximum loose thickness with each layer compacted to at least 95 percent of the modified maximum dry density (MMDD) and within 2 percent of the optimum moisture Content for modified compaction.

Conform to the following:

Table - Grading - Select fill

AS SIEVE (mm) PERCENT PASSING (DRY WEIGHT)

75.00 100

9.50 30-100

2.36 15-65

0.07 5-25

Table - Select Fill Properties

CBR, 4 day soaked at 95 percent MMDD to

AS 1289:

30 minimum

Plasticity Index 2-15 percent maximum

Linear Shrinkage 2-6 percent

For within 0.5m of building footprints, exposed subgrade soils should then be compacted to 98 percent relative to standard compaction at a moisture content within 1.5 percent of the optimum moisture content. A final test roll accompanied by careful visual inspection by an experienced geotechnical professional shall be undertaken to allow detection of any areas requiring removal or further Compaction.

3.6.3 Trench Backfilling

Backfill as rapidly as construction, testing, and acceptance of work permits. Place and compact backfill under structures and paved areas in 150 mm lifts to top of trench and in 150 mm lifts to 300 mm over pipe outside structures and paved areas.

SECTION 31 23 00.00 20 Page 13

3.7 BORROW

Where satisfactory materials are not available in sufficient quantity from required excavations, approved borrow materials shall be obtained as specified herein.

3.8 BURIED WARNING AND IDENTIFICATION TAPE

Provide buried utility lines with utility identification tape. Bury tape 300 mm below finished grade; under pavements and slabs, bury tape 150 mm below top of subgrade.

3.9 BURIED DETECTION WIRE

Bury detection wire directly above non-metallic piping at a distance not to exceed 300 mm above the top of pipe. The wire shall extend continuously and unbroken, from manhole to manhole. The ends of the wire shall terminate inside the manholes at each end of the pipe, with a minimum of 0.9 m of wire, coiled, remaining accessible in each manhole.

The wire shall remain insulated over it's entire length. The wire shall enter manholes between the top of the corbel and the frame, and extend up through the chimney seal between the frame and the chimney seal. For force mains, the wire shall terminate in the valve pit at the pump station end of the pipe.

3.10 FINISH OPERATIONS

3.10.1 Grading

Finish earthworks to a smooth compacted and uniform surface within the following limits:

a. Formation Width: Not less than specified.

b. Subgrade Surface: Maximum 25 mm below and not above specified level.

c. Subgrade Width: Not less than specified. Extend 150 mm minimum beyond the back of kerb. Refer to PROJECT SPECIFIC REQUIREMENTS in the RFT/RFQ.

d. Batter: Not steeper than the specified slope.

d. Maximum variation at any point from specified plane of batter shall be 150 mm in earth and 300 mm in rock.

e. Unpaved Areas / Table Drain Invert: Maximum 75 mm above or below specified level, free of depressions capable of ponding water.

Maximum 40 mm adjacent to kerbs.

Grade areas to drain water away from structures. Maintain areas free of trash and debris. For existing grades that will remain but which were disturbed by Contractor's operations, grade as directed.

3.10.2 Topsoil and Seed

Provide in accordance with landscape planting requirements.

3.10.3 Protection of Surfaces

Protect newly backfilled, graded, and topsoiled areas from traffic, erosion, and settlements that may occur. Repair or reestablish damaged grades, elevations, or slopes.

SECTION 31 23 00.00 20 Page 14

3.11 DISPOSITION OF SURPLUS MATERIAL

Remove from Government property surplus or other soil material not required or suitable for filling or backfilling, and brush, refuse, stumps, roots, and timber.

3.12 FIELD QUALITY CONTROL

3.12.1 Sampling

ake the number and size of samples required to perform the following tests.

3.12.2 Testing

Undertake testing in accordance with requirements of Standard Specification for Roadworks NTG (V 4.1) NTMTM NT.

-- End of Section --

SECTION 31 23 00.00 20 Page 15

2.6 DETECTION WIRE FOR NON-METALLIC PIPING