Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
TABLE OF CONTENTS
1.0
1.1
1.2
1.3
1.4
2.0
2.1
2.2
2.3
3.0
3.1
3.2
3.3
3.4
3.5
3.6
4.0
4.1
4.2
4.3
GENERAL .......................................................................................................... 1
SECTION CONTENT ....................................................................................... 1
CROSS REFERENCES ................................................................................... 1
DEFINITIONS .................................................................................................. 1
MEASUREMENT ............................................................................................. 2
QUALITY ............................................................................................................ 2
INSPECTION ................................................................................................... 2
SAMPLES ........................................................................................................ 3
CONTRACTOR’S SUBMISSIONS ................................................................... 3
SITE MANAGEMENT ......................................................................................... 3
TREE PROTECTION ....................................................................................... 3
TREES TO BE RETAINED .............................................................................. 4
WORK NEAR TREES ...................................................................................... 4
EXISTING SERVICES ..................................................................................... 5
DEWATERING................................................................................................. 5
SITE RESTORATION ...................................................................................... 5
SITE CLEARING ................................................................................................ 6
SITE CLEARING.............................................................................................. 6
REMOVAL OF TOPSOIL ................................................................................. 6
STOCKPILES .................................................................................................. 6
5.0
TOLERANCES ................................................................................................... 7
6.0
COMPACTION.................................................................................................... 8
6.1
6.2
6.3
6.4
7.0
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
8.0
8.1
METHOD OF COMPACTION AND TESTING .................................................. 8
COMPACTED LAYER METHOD OF CONSTRUCTION .................................. 8
MECHANICAL INTERLOCK METHOD OF CONSTRUCTION......................... 9
DENSITY AND MOISTURE REQUIREMENTS ................................................ 9
EXCAVATION................................................................................................... 11
GENERAL...................................................................................................... 11
SURFACE DRAINAGE .................................................................................. 11
PROVISIONAL DEPTHS ............................................................................... 11
EXPLOSIVES ................................................................................................ 11
BEARING SURFACES .................................................................................. 12
REINSTATEMENT OF EXCAVATION ........................................................... 12
ADJACENT STRUCTURES ........................................................................... 12
NON-RIPPABLE MATERIAL.......................................................................... 13
FILLING ............................................................................................................ 14
FILL MATERIAL ............................................................................................. 14
December 2001
i
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
8.2
8.3
9.0
PREPARATION FOR FILLING ...................................................................... 14
PLACING FILL ............................................................................................... 15
SUBGRADE PREPARATION ........................................................................... 15
10.0 DRAINAGE AND OTHER SERVICE TRENCHES ............................................ 16
10.1 TESTING ....................................................................................................... 16
10.2 EXCAVATING ................................................................................................ 17
10.3 PIPE SURROUND ......................................................................................... 18
10.4 BACKFILLING................................................................................................ 18
10.5 TRENCH RESTORATION ............................................................................. 20
10.5.1 General ................................................................................................... 20
10.5.2 Surface Profile Tolerances ...................................................................... 20
10.5.3 Grassed Areas......................................................................................... 20
10.5.4 Unit Paving .............................................................................................. 20
10.5.5 Rigid (Concrete) Pavement...................................................................... 20
10.5.6 Flexible (Asphalt) Pavement .................................................................... 21
11.0 SERVICE CONDUIT INSTALLATION .............................................................. 24
11.1
11.2
11.3
11.4
11.5
GENERAL...................................................................................................... 24
BORING OR JACKING .................................................................................. 24
INSTALLATION ............................................................................................. 25
MARKING SERVICES ................................................................................... 25
TESTING ....................................................................................................... 25
12.0 GEOTEXTILES ................................................................................................. 26
13.0 GABIONS AND MATTRESSES ....................................................................... 27
13.1 MATERIALS .................................................................................................. 27
13.2 EXECUTION .................................................................................................. 28
14.0 ROCK SCOUR PROTECTION ......................................................................... 29
15.0 ROCK FILLING................................................................................................. 30
16.0 BARRIERS AND MEMBRANES....................................................................... 30
17.0 RETAINING WALLS ......................................................................................... 30
17.1 CRIB WALLS ................................................................................................. 30
17.2 EARTH REINFORCEMENT ........................................................................... 31
18.0 GROUND ANCHORS ....................................................................................... 32
18.1 GENERAL...................................................................................................... 32
18.2 EXECUTION .................................................................................................. 32
December 2001
ii
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
1.0
GENERAL
1.1
SECTION CONTENT
Ground works generally, protection of trees, site clearing, excavation, placing and
compacting fill, drainage and service trenches, installation of service conduits,
installation of geotextile, gabions and mattresses, sluiced rock fill, crib walls, earth
reinforcement and ground anchors.
1.2
CROSS REFERENCES
Refer to the following other Reference Specifications:
 S110 General Requirements: General technical requirements and interpretation of
terminologies.
 S120 Quality: Process control testing.
 S150 Roadworks: Kerb and channel, concrete paving, flexible pavement, other road
surface elements.
 S160 Drainage: Bedding requirements for drainage pipes.
 S170 Stonework: Stone pitching and scour protection.
 S180 Unit Paving: Base preparation and bedding requirements for unit paving.
 S190 Landscaping: Earth mounds, rock landscaping, subsoil preparation, placing
topsoil, and temporary grassing.
 S200 Concrete Work: Working bases, underlays to slabs on ground and
membranes.
 S300 Quarry Products: Subgrade replacement material, trench backfill material, and
filter material requirements for side drain, mitre drain, and pavement drainage
blanket course.
1.3
DEFINITIONS
Description and classification of soils: To AS 1726.
Bad ground: Ground unsuitable for the purposes of the Works, including filling liable to
subsidence; ground full of vegetative matter; ground containing cavities, faults or
fissures; ground contaminated by harmful substances including oil, cement and
chemicals; ground containing acid sulphate soil; or ground which is or becomes soft,
wet and unstable; and the like.
Non-rippable material: As defined in Clause 7.8.
Line of influence: A line extending downward and outward from the bottom edge of a
footing, slab or pavement and defining the extent of foundation material having
influence on the stability or support of the footings, slab or pavement.
Subgrade: The prepared formation on which a pavement or slab is constructed or the
top portion of earthworks immediately below the pavement or slab. Subgrade is
considered to be the top 150 mm in cuttings and the top 300 mm in embankment unless
stated otherwise.
Subgrade level: The top surface of the prepared subgrade on which a pavement or slab
is constructed.
Relative compaction: The ratio between the field bulk density and the bulk density of the
material when compacted in the laboratory.
December 2001
1
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
Critical zone (trees): The area described by the greater of the vertical projection of the
canopy or a radius of ten times the tree trunk diameter and extending to a depth of
750 mm below the ground.
1.4
MEASUREMENT
General
If provisional quantities are specified, or there have been variations to the contract
dimensions of excavations, do not commence backfilling or place any permanent work
in excavations until the quantities of excavation and backfilling have been agreed and
recorded.
Measurement of non-rippable material
If payment is to be claimed for excavation in non-rippable material, do not remove the
material until the level and (if applicable) class of material have been determined.
2.0
QUALITY
2.1
INSPECTION
Witness points
Refer annexure. Give sufficient notice so that inspection may be made of the following
stages:
 Protection measures in place for trees to be retained.
 Areas to be cleared and/or stripped of topsoil marked out.
 Excavation completed to contract levels or founding material.
 Subgrade material opened up so that its nature can be assessed.
 Geotextile in place prior to backfilling.
 Trenches excavated before laying the service or drain.
 Services or drains laid in trenches and ready for backfilling.
 Any boring or jacking operation.
 Service conduits ready for testing.
 Reinforced earth wall faces at the factory ready for delivery to site.
 At the commencement of installing reinforced earth wall faces.
Hold points
Refer annexure. Do not proceed without approval. Give sufficient notice so that
inspection may be made at the following stages:
 Subgrade ready to receive sub base, base, working base, geotextile or membrane,
as applicable.
Immediate notice
If rock or bad ground is encountered, give notice immediately and obtain instructions.
December 2001
2
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
2.2
SAMPLES
General
Refer annexure. Submit to the testing authority samples of the following:
 Each type of imported fill.
 Each type of excavated material, which is to be re-used as select fill or embankment
fill in the Works.
Identification
Attach a tag to each sample showing relevant information including description, source
and nominal size of material.
Earth reinforcement
Provide samples of the following, before fabrication commences:
 Facing unit (at the approval of the Superintendent, facing units of the same design
installed at a nearby project may be used in lieu of the facing unit sample).
 Reinforcing anchor to facing unit joint
2.3
CONTRACTOR’S SUBMISSIONS
Design
Ground anchors: Submit all details of the proposed ground anchor system prior to
commencement of work.
Earth reinforcement: Submit an engineer's certificate confirming compliance with
Queensland Department of Main Roads standard specification MRS11.06 Reinforced
Soil Structures and this specification.
Materials
Imported materials: Notify the supplier, source and suppliers description of all imported
materials.
Recycled products: Notify the nature, source, proportions and method of incorporation
of any added fillers or binders.
Imported fill: Submit certification or test results, which establish the compliance of
imported fill.
3.0
SITE MANAGEMENT
3.1
TREE PROTECTION
Warning sign
General: Display a sign, in a prominent position at each entrance to the site, warning
that trees and planting are to be protected during construction. Remove on completion.
Lettering: Road sign type sans serif letters, 100 mm high, in red on a white background,
to AS 1744.
December 2001
3
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
3.2
TREES TO BE RETAINED
Requirement
Retain all trees outside the site. Retain all trees within the site that are shown on the
Drawings to be retained and any others that it is not necessary to remove. Refer
annexure.
Marking
Mark trees to be retained within the site by visible, durable tags lettered to conform with
the tree number (if any) on the Drawings. Secure the tag to the tree by a loose band of
yellow plastic "barrier tape". Remove the tags on completion.
Protection and repair
Protection: Protect from damage the trees and shrubs that are to be retained, including
those beyond the site area, both above and below ground.
Repair: Repair trees damaged during the work by a certified arborist.
Tree enclosure
Location: Erect fence around trees to be retained within the site, and around trees
outside the site but within the operating range of machinery.
Fencing: Provide a minimum 1.8 m high rigid fence. Install protective device before
commencement of work and remove on completion.
Large ovate tree canopy: Erect fence at the tree drip line perimeter.
Column type tree canopy: Erect fence at varying distances from the stem, depending on
the tree diameter in terms of depth breast height. Provide minimum clear distances of
3 m for tree diameter up to 30 cm, 4 m for tree diameter greater than 30 cm and up to
50 cm, and 5 m for diameter larger than 50 cm.
Removal
If repair work is impracticable, or is attempted and is rejected, remove the tree
(including the root system if directed), make good, and either replace the tree with a
replacement tree of the same species and similar size, or pay damages. The value of
any tree removed must be calculated in accordance with the publication A System of
Assigning a Monetary Value to Amenity Trees (Australian Institute of Horticulture Inc,
Technical Memorandum No. 2, 1996). Refer annexure.
3.3
WORK NEAR TREES
Harmful materials
Do not store or place harmful materials under or near trees.
materials such as cement from harming trees and plants.
Prevent wind-blown
Damage
Prevent damage to tree bark. Do not attach stays, guys and the like to trees.
December 2001
4
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
Work under trees
General: Do not add or remove topsoil within the drip line of trees. Do not fill against
tree trunks, even temporarily.
Excavation: Open up excavations under tree canopies for as short a period as possible.
Hand methods: Use hand methods to locate, expose and cleanly remove the roots on
the line of excavation. If it is necessary to excavate within the critical zone, use hand
methods such that root systems are preserved intact and undamaged.
Roots
Where it is necessary to cut tree roots in excess of 50 mm diameter, use means such
that the cutting does not unduly disturb the remaining root system. Immediately after
cutting, apply a bituminous fungicidal sealant to the cut surface.
Backfilling
Backfill excavations around tree roots with a mixture consisting of three parts by volume
of topsoil and one part of well rotted compost with a neutral pH value, free from weed
growth and harmful materials. Place the backfill in layers each of 300 mm maximum
depth and compact to a dry density similar to that of the surrounding soil. Immediately
after backfilling, thoroughly water the root zone surrounding the tree.
Compacted ground
Avoid unnecessary compaction of the ground under trees. Do not stockpile materials
within the drip line. Do not permit vehicles or machinery to be parked within the drip
line. Do not permit vehicles or machinery to pass under trees if practicable alternatives
exist. If compaction (of areas within the drip line but not occupied by the Works)
nevertheless occurs, seek instructions.
3.4
EXISTING SERVICES
Marking
Before commencing ground works, locate and mark existing underground services in
the areas that will be affected by the earthworks operations.
3.5
DEWATERING
Keep earthworks free of surface water. Provide and maintain slopes, crowns and drains
on excavations and embankments to ensure satisfactory drainage. Place construction
including filling, paving, structures and services, on ground from which surface water
has been removed. Protect freshly laid work from water damage.
3.6
SITE RESTORATION
Requirement
Where existing ground surfaces are not required to be varied as part of the Works,
restore them to the condition existing at the commencement of the work under the
Contract.
December 2001
5
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
4.0
SITE CLEARING
4.1
SITE CLEARING
Timing
Do not clear any area until commencement of other work in the area is imminent.
Extent
General: Clear only the site areas to be occupied or affected by the Works and any
other areas that the Contract specifically requires to be cleared.
Contractor's site areas: If not included within the areas specified above, clear generally
only to the extent necessary for the performance of the Works.
Clearing operations
General clearing: Remove everything on or above the site surface, including rubbish,
vegetable matter and organic debris, scrub, trees, timber, stumps, boulders and rubble.
Remove standing grass to a depth just sufficient to include the root zone. Strip surface
grasses with the topsoil.
Grubbing: Grub out stumps and roots over 75 mm diameter to a minimum depth of
500 mm below subgrade under buildings and pavement, or 300 mm below finished
surface in other areas.
Old works: Remove old slabs, foundations, retaining walls, paving, abandoned services
and the like to a depth of 300 mm below existing or finished surface or 500 mm below
subgrade level (whichever is lower).
Refilling: Unless otherwise specified, refill grub holes and the like with material similar to
the surrounding soil.
4.2
REMOVAL OF TOPSOIL
Extent
Remove topsoil to a depth of 100 mm from site areas to be occupied or affected by
Works such as structures, paving, excavations, embankments and regrading and any
other areas the Contract requires. If topsoil extends to a depth greater than 100 mm,
obtain direction.
4.3
STOCKPILES
Wherever practical, transfer topsoil directly for use as planting media. Where
stockpiling of topsoil is required, establish stockpiles in approved locations, to heights
not exceeding 1.5 m. Provide adequate drainage and erosion protection. Do not burn
off to remove plant growth that may occur during storage. Do not allow traffic on
stockpiles. If a stockpile of topsoil is to remain for more than four weeks, sow with
temporary grass.
December 2001
6
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
5.0
TOLERANCES
Surface level
General: Provide finished subgrade that is evenly graded between level points, free
draining and conform to the required tolerances.
Smoothness: As normally produced by a grader blade (except for batters without
topsoil).
Tolerances: The limits in the Table 5.1 apply to the finished surface unless overridden
by the requirements for the finished level and thickness of the surfacing.
Table 5.1 - Tolerances
Item
Absolute
Level tolerance
Relative to a 3 m straightedge*
Cut subgrade level in earth and fill
subgrade level
+ 0 mm
- 50 mm
15 mm
Cut subgrade in rock
+ 0 mm
- 75 mm
Unspecified
* Limits to incorporate due allowance for design shape where relevant
Other ground surfaces
Absolute level tolerance:  50 mm, provided the area matches adjacent construction.
Horizontal surfaces
Absolute tolerance:  50 mm, except where alignment with an existing road structure is
necessary. Join new construction to the existing work in a smooth manner.
Batters
Slope: Average slope not steeper than shown on the Drawings nor more than 10
flatter, provided that flatter slopes do not encroach on abutting property.
Absolute level tolerance: For cut batters in earth,  150 mm and for cut batters in rock
and for fill batters,  300 mm; both measured from the average slope plane.
Topsoil to batters: Absolute level tolerance  50 mm, provided the area matches
adjacent construction.
December 2001
7
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
6.0
COMPACTION
6.1
METHOD OF COMPACTION AND TESTING
Requirement: Select the methods of compaction and compliance testing to suit the
material category listed in Table 6.1.
Table 6.1 - Compaction method
6.2
Material category
Compaction method
Density compliance tests
1.
Cohesionless sand
Compacted layer
method
Relative dry density or
density index (if RDD gives
meaningless answers)
2.
Soils other than 1 above which, after
compaction, have less than 20% of
stone retained on the 37.5 mm sieve
Compacted layer
method
Relative dry density
3.
Coarse granular soils with more than
70% of stone retained on the
37.5 mm sieve
Mechanical interlock
method
Nil on material in general
4.
Soils other than 3 above which, after
compaction, have 20%-70% of stone
retained on the 37.5 mm sieve
Compacted layer
method
or
Mechanical interlock
method
Relative dry density
RDD where appropriate on
the finer grained materials
which completely fill the
voids between rocks
COMPACTED LAYER METHOD OF CONSTRUCTION
Stone size: Limit stone size in fill material to less than two-thirds of the uncompacted
layer depth.
Execution: Place and compact fill material uniformly in layers.
Compaction layer thickness: Comply with Table 6.2 for the allowable loose layer
thickness for the location and properties of the material being compacted. Where the
uncompacted thickness of a layer would otherwise be less than the specified minimum
thickness, a lesser thickness of newly placed material may be employed by loosening
the underlying material to give a total depth equal to the minimum thickness.
Table 6.2 - Layer thickness for compaction
Loose layer thickness (mm)
Minimum
Maximum
Material/ location
General fill in road embankment
150
300
Clay fill in water retaining structures
150
200
Subgrade
100
200
-
100
150
300
Backfill other than sand
Sand backfill
December 2001
8
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
6.3
MECHANICAL INTERLOCK METHOD OF CONSTRUCTION
Execution: Place and compact coarse granular fill material uniformly in layers. Roll
each layer until no permanent visible lowering of the surface occurs.
Minimum thickness of uncompacted layers: Greater of 150 mm or 1.5 times the
maximum rock size in the layer.
Maximum thickness of uncompacted layers: Comply with Table 6.3 for the specified
module weights, which apply to both drawn and self-propelled single drum rollers.
Interpolate layer thickness for module weights between the listed values.
Table 6.3 - Maximum thickness of uncompacted layers
Static module weighty or vibrating
drum equivalent (tonnes)
*
6.4
Maximum thickness of uncompacted layer (mm)
Voids not filled
Voids filled*
5
400
300
10
600
400
15
900
600
20
1200
800
Proportion of finer grained materials to completely fill the voids between rocks
DENSITY AND MOISTURE REQUIREMENTS
Density requirements: Compact fill and unbound subgrade material to the relevant
standards specified in Table 6.4. Refer annexure.
Moisture content: Unless specified otherwise in the annexure, adjust moisture content of
fill and unbound subgrade material as necessary to within 80-100% of the optimum
moisture content (determined by AS 1289.5.1.1) to achieve the required compaction.
Maintain moisture content of the compacted material within the specified range until
covered with subsequent layers. Refer annexure.
December 2001
9
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
Table 6.4 - Minimum density schedule
Minimum relative
compaction (standard)
(Cohesive soils generally)
(see Notes 1, 2, 3, 4)
Minimum density index
(Cohesionless soils)
(see Notes 1, 5)
Single one or two storey residential
dwelling sites
(a) Allotment fill
(b) Building pad (see Note 6)
95%
100%
65%
80%
Commercial, industrial and multi
unit residential developments
(a) Allotment fill
(b) Building pad (see Note 6)
98%
100%
70%
80%
Road and structural (other than
building) formations including
embankments, footpaths, paved
areas and shoulders (see Note 7)
(a)  0.3 m below subgrade level
(b)  0.3 m below subgrade level
95%
100%
65%
80%
All other areas eg parks
(a)  0.3 m below design level
(b)  0.3 m below design level
90%
95%
62%
65%
Replacement of unsuitable or overexcavated subgrade material
100%
80%
Backfilling of grub holes
100%
80%
Location
Notes:
1.
2.
3.
4.
5.
6.
7.
Field dry density to AS 1289.5.3.1, AS 1289.5.3.5 or AS 1289.5.8.1. If using AS 1289.5.8.1,
calibrate the surface moisture-density gauge in accordance with AS 1289.5.8.4 before use on
site.
Standard maximum dry density to AS 1289.5.1.1.
Relative compaction (% of maximum dry density) to AS 1289.5.4.1.
For plastic soils, compact soils designated under the unified classifications system as OH CH
MH to not less that 92% nor greater than 96% of standard maximum dry density at moisture
contents of between 90% and 120% of optimum moisture content.
Density index to AS 1289.5.6.1. Maximum and minimum dry densities to AS 1289.5.5.1.
Average imposed bearing pressure of floor slab not to exceed 20 kPa. Imposed bearing
pressures of strip and pad footings not to exceed 100 kPa.
In the context of this specification, road formation is deemed to include all the area within the
designated road reserve. Structural formation is deemed to include the area under the
paving plus a nominal 1 m from the edge of the paved area.
December 2001
10
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
7.0
EXCAVATION
7.1
GENERAL
Extent
Site surface: Excavate over the site to give correct levels and profiles as the basis for
construction, paving, filling, landscaping and the like. Make allowance for compaction
or settlement.
Footings: Excavate for footings, pits, wells, shafts and the like, to the required sizes and
depths. Confirm that the bearing capacity is as specified.
Preparation
Prior to excavating, cut any pavement wearing surface, concrete footpath, kerb and
channel or the like by saw or other approved means to give a clean break line along the
edge of excavation.
Existing footings, slabs and pavements
If excavation is required below the line of influence of an existing footing, slab or
pavement, use methods that maintain the support of the footing, slab or pavement and
ensure that the structure and finishes supported by the footing are not damaged. Refer
annexure.
7.2
SURFACE DRAINAGE
Catch drains
Construct catch drains at the top of cuttings. Grade and trim the catch drains to ensure
the free flow of water and connect to the drainage system. Install erosion protection
measures where necessary.
Table drains
Profile: Neatly trim earth table drains to the required profile, grade and alignment.
Install erosion protection measures where necessary.
Grading: Construct table drains with a minimum grade of 0.5% and with a maximum
length of 50 m before diversion to drainage system.
7.3
PROVISIONAL DEPTHS
Contract depths
The footing or pier depths shown on the Drawings are only a basis for measurement of
quantities. Actual excavation levels will be determined on the basis of material
encountered.
7.4
EXPLOSIVES
Do not use explosives. Refer annexure.
December 2001
11
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
7.5
BEARING SURFACES
General
Provide horizontal bearing surfaces for load bearing elements including footings. Step
to accommodate level changes. Make the steps to the appropriate courses if
supporting masonry.
Deterioration
If the bearing surface deteriorates after approval, excavate further to a sound surface
before placing the load bearing element.
7.6
REINSTATEMENT OF EXCAVATION
General
Where excavation exceeds the required extent, whether as a result of bad ground (and
where footing levels or the like are not varied) or as a result of excess excavation,
reinstate to the correct depth and required bearing value.
Particular
Within the ‘line of influence’ of footings, beams or other structural elements: Refill overexcavation with concrete of strength appropriate to the loading, minimum 15 MPa.
Refer annexure.
Below slabs or pavements: Refer to Clause 9.0.
7.7
ADJACENT STRUCTURES
Temporary supports
General: Provide supports to adjacent structures where necessary, sufficient to prevent
damage arising from the works.
Lateral supports: Provide lateral support using shoring.
Vertical supports: Provide vertical support where necessary using piling or underpinning
or both.
Permanent supports
If permanent supports for adjacent structures are necessary and are not described, give
notice and obtain instructions.
Encroachments
If encroachments from adjacent structures are encountered and are not shown on the
drawings, give notice and obtain instructions.
Rock bolting
Provide proprietary high strength steel bars or tubes anchored into holes drilled in the
rock and tensioned against plates bearing on the rock face to provide temporary or
permanent support for the rock face. Refer Clause 18.0.
December 2001
12
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
7.8
NON-RIPPABLE MATERIAL
General
Where the methods of measurement require differentiation of non-rippable material, the
following criteria apply. Machine classification to AS 2868.
Confined excavation
Definition: Excavation of trenches and to broader areas less than 1000 m2 in extent.
Classification: Classify material as non-rippable if any of the nominated classes of
crawler excavator fitted with a heavy duty bucket, cannot rip at a production rate (in situ
volume) exceeding the nominated values. Fit bucket teeth with high penetration boots,
approved by the machine manufacturer for use on the particular machine in rock.
Class 55 crawler excavator fitted with a maximum 450 mm wide bucket: Maximum
production rate 1.5 m3 per hour.
Class 85 crawler excavator fitted with a maximum 600 mm wide bucket: Maximum
production rate 3 m3 per hour.
Class 115 crawler excavator fitted with a maximum 750 mm wide bucket: Maximum
production rate 4.5 m3 per hour.
Class 155 crawler excavator fitted with a maximum 900 mm wide bucket: Maximum
production rate 7 m3 per hour.
Class 200 crawler excavator fitted with a maximum 1050 mm wide bucket: Maximum
production rate 10 m3 per hour.
Other excavation
Classification: Classify material as non-rippable if the nominated classes of crawler
tractor, equipped with a heavy duty, single tine parallelogram ripper (approved by the
machine manufacturer for use on the particular machine in rock), cannot rip at a
production rate (in situ volume) exceeding the nominated values.
Class 150C crawler tractor: Maximum production rate of 50 m3 per hour.
Class 200C crawler tractor: Maximum production rate of 75 m3 per hour.
Class 300C crawler tractor: Maximum production rate of 90 m3 per hour.
Class 400C crawler tractor: Maximum production rate of 105 m3 per hour.
Class 500C crawler tractor: Maximum production rate of 120 m3 per hour.
Class 600C crawler tractor: Maximum production rate of 135 m3 per hour.
December 2001
13
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
8.0
FILLING
8.1
FILL MATERIAL
General
Material type: Inorganic, non-perishable material.
Sulphur content: Do not use filling with sulphur content exceeding 0.5% within 0.5 m of
cement bound elements (for example concrete structures or masonry), unless such
elements are protected by impermeable membranes or by other suitable means.
Sources
Where directed, re-use material recovered from excavations on the site.
recovered material as necessary prior to use.
Dry out
Fill types
General fill: Well graded material, maximum particle size 75 mm, plasticity index  55%.
Select fill: Granular material complying with the following properties.
 Particle size: 75 mm maximum.
 Proportion passing 0.075 mm sieve: 25% maximum.
 Plasticity index:  2%,  15%.
 Soaked CBR: Not less than 15.
Road embankment fill: Well graded material with maximum plasticity index 35% and
maximum particle size determined by location and layer thickness, but not exceeding
two-thirds of the uncompacted layer thickness.
Fill subgrade: Use class 3 material or select fill.
Special fill: Refer annexure.
8.2
PREPARATION FOR FILLING
General
Remove loose material, debris and organic matter.
Benching
If filling is to be placed against a ground surface that slopes more than 1V:4H, bench
into the natural surface for at least 1 m at every 1 m change of level to form a key for
the filling.
Under ground slabs, pavements and other load bearing elements
Under filling that will support slabs, pavements and other load-bearing elements,
compact the stripped surface as for filling. If necessary loosen the material to a depth of
200 mm and adjust the moisture content.
Under earth mounds
Cultivate the ground by ripping to a depth of 200 mm before mound formation.
Rock
Remove any overhanging rock ledges. Remove any loose or unstable blocks of rock.
December 2001
14
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
8.3
PLACING FILL
General
Layers: Place and compact fill in accordance with the compacted layer method of
construction specified in Clause 6.2 to achieve the density specified in Clause 6.4.
Placing at structures
General: Place and compact filling in layers simultaneously on both sides of structures,
culverts and pipelines to avoid differential loading. Commence compaction of each
layer at the structure and proceed away from it.
Placing against concrete: Do not place fill against concrete until the concrete strength is
more than 80% of the specified strength.
Supports: Remove any temporary supports to excavations progressively as backfilling
proceeds.
9.0
SUBGRADE PREPARATION
General
Trim the subgrade to an even surface free from loose material.
Compaction
Compact, or recompact, subgrade material to obtain the density specified in Clause 6.4.
Subgrade affected by moisture
Where the subgrade is unable to support construction equipment, or it is not possible to
compact the overlying pavement because of a high subgrade moisture content, perform
one or more of the following:
 Allow the subgrade to dry until it will support equipment and allow compaction.
 Scarify the subgrade to a depth of 150 mm, work as necessary to accelerate drying,
and recompact when the moisture content approximates the optimum.
 Excavate the wet material and replace with class 3 material or select fill.
 Treat the material with lime mixed in by approved specialised plant.
Side drain, mitre drain and blanket course
General: Construct pavement drainage system to comply with Standard Drawing
UMS 261. For roads, construct side drains on both sides unless directed otherwise.
Material: Conform to the filter material requirements of S300 Quarry Products
Clause 4.4.
Construction: Do not allow construction equipment to travel or stand directly on
constructed subsoil drains.
Springs or seeps
If springs or seeps are found, provide drainage as directed.
Draining depressions
If subgrade is replaced, grade depressions in the native material to drain to the subsoil
drainage system or connect by mitre drains.
In rock subgrades, drain depressions with subgrade drains at least 150 mm wide,
backfilled with coarse filter, and connected to the subsoil drainage system.
December 2001
15
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
Unsuitable material
Remove roots, boulders, silt, organic matter and other unsuitable materials.
Remove or lime treat subgrade with a soaked CBR less than 3 to a depth of 150 mm. If
removed, replace with class 3 material or select fill.
Backfilling
Reinstate over-excavation, including excavation for grub holes to the correct level with
class 3 material or select fill and compact to comply with Clause 6.4.
Rectification
If a section of subgrade material fails to meet the required density after compaction,
rework or rectify as follows:
 Fill subgrades: Remove the non-complying material, replace with class 3 material or
select fill and recompact.
 Cut subgrades: Rework the material, or replace with class 3 material or select fill
and recompact.
Proof rolling
Timing: Following completion of subgrade compaction and trimming, inspect the whole
of the subgrade area by proof rolling with a fully loaded single rear axle truck (or
acceptable equivalent).
Acceptance of subgrade: No visible signs of deformation or instability in the subgrade
during proof rolling.
10.0 DRAINAGE AND OTHER SERVICE TRENCHES
10.1 TESTING
General
Scope: Testing is not required for isolated patches less than 2 m2 in size. Patches are
usually associated with the installation of service connections or carrying out repair
work. Patches are typically characterised by width to length ratios less than two.
Test frequencies
Backfilling: 1 field density test per 2 layers for every 40 linear metres of trench or for the
part thereof.
Unbound pavement: 1 in situ density test per single compacted layer of work for every
40 linear metres of trench or for the part thereof.
Asphalt: 1 density test per single compacted layer of work for every 40 linear metres of
trench or for the part thereof.
December 2001
16
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
10.2 EXCAVATING
Existing surfaces
Saw cutting: Before excavating trenches, saw cut existing concrete and bituminous
surfaces to provide a straight even joint during the work. In road carriageway, saw cut
at least 150 mm clear of the trench walls. In road verge, saw cut at least 75 mm clear of
the trench walls. Position saw cut to coincide with any grooved pattern line or
contraction joint or expansion joint in concrete paving, if the saw cutting is undertaken
within 600 mm of these elements.
Unit paving: Lift and store unit paving for later reinstatement.
Excavation
Alignment: Excavate for underground services to the required lines, levels and grades.
Generally make the trenches straight between personnel access ways (manholes),
inspection points and junctions, with vertical sides and uniform grades.
Timing: Unless approved otherwise by the Superintendent, excavate trench before any
paving or topsoiling and grassing operations.
Trench widths
Keep trench widths to the minimum consistent with the laying and bedding of the
relevant service and construction of personnel access ways and pits. For drainage
trenches, comply with Standard Drawing UMS 311.
Trench depths
Excavate as required by the relevant Service Authority to achieve at least the minimum
cover specified in Clause 11.1.
Shoring of trench and excavation: Where required, erect and maintain shoring where
the depth of excavation exceeds 1.5 m.
Support of adjacent construction
Provide support in accordance with Clause 7.7.
Obstructions
Clear trenches of sharp projections. Cut back roots encountered in trenches to at least
600 mm clear of services. Remove other obstructions including stumps and boulders,
which may interfere with services or bedding.
Dewatering
Keep trenches free of water. Place bedding material, services and backfilling on firm
ground free of surface water.
Excess excavation
If trench excavation exceeds the correct depth, ensure that the surface of the native
material is uniformly graded (that is free of low spots) and reinstate to the correct depth
and bearing value using compacted bedding material or grade N20 concrete.
December 2001
17
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
10.3 PIPE SURROUND
Provide a continuously supported pipe surround (comprising pipe bedding, haunch, side
and overlay zones) in accordance with the requirements of the relevant Service
Authority. For drainage pipes, comply with the requirements of S160 Drainage
Clause 3.2.3.
10.4 BACKFILLING
General
Extent of backfill: Above the pipe surround but terminate at the underside of the
pavement, that is, at the subgrade level. Do not cause discontinuity in the pavement
structure.
Timing: Backfill trenches as soon as possible after the pipe or service has been laid and
bedded, if possible on the same working day.
Compaction standard: In accordance with Clause 6.4.
Puddling and jetting: Do not employ construction operations that involve puddling or
jetting of material, unless prior approval is obtained from the Superintendent.
Construction loads: Select an appropriate compaction plant compatible with the
minimum pipe cover to the service. Comply with the requirements of Standard Drawing
UMS 301 or UMS 302 for concrete pipes.
Permitted materials
Material selection: Choose backfill material to suit the permeability characteristics of the
surrounding soil to ensure that the completed trench does not hold water nor obstruct
existing drainage paths through the soil.
Under road carriageways: Granular fill in stormwater drainage trenches or trenches in
permeable soils (Figures 10.1 and 10.3). Class 3 material or stabilised sand or
controlled low strength material or lean mix concrete in trenches where free drainage
points are not available or trenches in impermeable soils (Figures 10.2 and 10.4). Lean
mix concrete in isolated patches less than 2 m2 in size.
Under footpaths and bikeways: Excavated material, provided adequate compaction can
be obtained. Alternatively use class 3 material or stabilised sand or controlled low
strength material or lean mix concrete in trenches where free drainage points are not
available or trenches in impermeable soils. Use granular fill or sand in trenches where
free drainage points are available or trenches in permeable soils.
Permeability characteristics
Field test: Collect a handful of representative soil material, discarding particles larger
than 10 mm in diameter. Spray a fine water mist evenly throughout the soil particles to
achieve the optimum moisture content. Mould the moist sample by hand pressure. The
soil material is considered relatively impervious if the moulded sample remains intact
after being tossed lightly from one hand to the other. The soil material is considered
relatively permeable if there is difficulty in maintaining the moulded shape or the
moulded sample crumbles after being tossed lightly from one hand to the other.
Permeable soils: Generally coarse grained soils including sand, gravel, sand-gravel
mixture. A soil is of basic type sand or gravel if, after the removal of any cobbles or
boulders, over 65% of the material is of sand and gravel sizes.
December 2001
18
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
Impermeable soils: Generally fine grained soils including clay, silt, gravelly or sandy
clay, gravelly or sandy silt. A soil is of basic type silt or clay if, after the removal of any
cobbles or boulders, over 35% of the material is of silt and clay sizes.
Material characteristics
Granular fill: Crushed rock 75 mm maximum size, non plastic open graded material or
crusher run recycled concrete.
Class 3 material: Comply with the requirements of S300 Quarry Products.
Excavated material: Well graded inorganic non-perishable material, maximum size
75 mm, plasticity index  55%.
Stabilised sand: 1 part either Type GP or Type GB cement to 12 parts sand (by volume)
mixed with a minimum quantity of water sufficient to allow ease of placement and
compaction.
Controlled low strength material: An approved proprietary cementitious flowable fill.
Provide 28 day compressive strengths of 0.5 - 2.0 MPa under footpaths and 3 - 5 MPa
under roads. Place material by discharging directly from a concrete agitator truck.
Alternatively use a concrete pump where access is a major problem.
Lean mix concrete: Achieve 28 day characteristic compressive strength of 5 MPa for
concrete. Use nominal maximum aggregate size of 40 mm. Achieve target slumps of
80 - 100 mm for wet concrete and less than 15 mm for dry concrete.
Sand: Natural sand or manufactured sand or a blend of natural and manufactured sand,
comprising hard durable particles. Comply with Table 10.1 for material properties.
Table 10.1 - Sand properties
Natural sand
Blended and
manufactured sand
100
100
% by weight passing the 0.075 mm A.S. sieve
5 maximum
20 maximum
Plasticity index
5 maximum
10 maximum
Property
% by weight passing the 6.7 mm A.S. sieve
Execution
Compacted layer method of construction: As specified in Clause 6.2. This construction
method applies to class 3 material, excavated material, dry stabilised sand, and dry lean
mix concrete.
Mechanical interlock method of construction: As specified in Clause 6.3.
construction method applies to granular fill.
This
Concrete compaction method: Deposit concrete in horizontal layers not exceeding
400 mm thick. Commence compaction of concrete immediately after deposition. Use
high frequency immersion vibrators to achieve compaction. This construction method
applies to wet lean mix concrete.
Puddling and jetting: Compact by flooding and the use of immersion vibrators. Flooding
is only permitted provided that the process does not cause damage to adjacent works.
This construction method applies to sand.
December 2001
19
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
10.5 TRENCH RESTORATION
10.5.1 General
Scope: This clause applies to trench restoration work associated with the installation
and maintenance of services placed in existing road carriageways, footpaths and
bikepaths.
Reinstatement of surfaces: Reinstate existing surfaces removed or disturbed by trench
excavations to match the texture, surface type and colour of the existing and adjacent
work. Join smoothly to adjacent work. Reinstate paved surfaces and other surface
features (such as line marking) disturbed or removed during excavation of trenches to
provide a structural adequacy and serviceability that is at least equal to that in existence
prior to the disturbance.
Sub-surface pavement drainage: Reinstate existing sub-surface drainage to comply with
Standard Drawing UMS 261.
Minor roads: Roads classified as local access (pavement types A or B) and
neighbourhood access (pavement type C).
Major roads: Roads classified from district access to arterial routes (pavement types D
to G).
10.5.2 Surface Profile Tolerances
Timing: Record surface profile tolerance measurement following completion (if required)
and within 30 days preceding the expiry date of the maintenance or defects liability
period. This period is deemed to be 12 months from the work completion date.
Paved roadway and paved pedestrian surfaces: Reinstate surfaces to match existing
features such as pit covers or driveways so that the pavement edges are within - 0 mm
to + 5 mm. Limit the maximum deviation relative to a 1.2 m straightedge to 5 mm,
unless the crown camber overrides this requirement.
Unpaved pedestrian areas: No visual evidence of surface irregularities.
10.5.3 Grassed Areas
Provide 100 mm of loam and turf over trench and other disturbed areas.
10.5.4 Unit Paving
Provide base course and bedding to match the existing. Reinstate using whole paving
units. Do not use concrete infill.
10.5.5 Rigid (Concrete) Pavement
Requirement: Reinstate concrete surfaces to the original level. Where specified, epoxy
grout steel dowels into the adjacent concrete and provide reinforcement to prevent the
reinstated concrete from subsiding or cracking. Comply with the requirements of
Table 10.2.
December 2001
20
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
Table 10.2 - Reinstatement of concrete pavement
Location
Concrete
type
Steel reinforcement
Thickness
Road
carriageways
Grade N32
minimum
Steel reinforcement as required by
Match adjacent concrete
design, provide 500 mm long (full length)
Y20 dowels spaced at 400 mm centres
Reinforced
concrete
footpaths
Grade N25
F72 mesh placed centrally, 300 mm long 100 mm or the adjacent
(full length) R12 dowels spaced at
concrete thickness,
400 mm centres
whichever is greater
Unreinforced
concrete
footpaths
Grade N25
Not required
Reinforced
concrete
bikepaths
Grade N25
F72 mesh placed centrally, 300 mm long 125 mm or the adjacent
(full length) R12 dowels spaced at
concrete thickness,
300 mm centres
whichever is greater
Unreinforced
concrete
bikepaths
Grade N25
Not required
75 mm or the adjacent
concrete thickness,
whichever is greater
100 mm or the adjacent
concrete thickness,
whichever is greater
10.5.6 Flexible (Asphalt) Pavement
Asphalt supply and placement
Asphalt manufacture: In accordance with S310 Supply of Dense Graded Asphalt.
Asphalt transportation and placement: In accordance with S320 Laying of Asphalt.
Tack coat (0.2 L/m2 residual bitumen) the sides and bottom. Lay and compact hot mix
asphalt so that the edges (saw cut or edge planed) are flush with the existing pavement.
A slight crown (maximum camber above the existing pavement of 5 mm for trench
 0.5 m wide or 10 mm for trench  0.5 m wide) may be formed to allow for subsequent
consolidation of the trench.
Asphalt spreading: Use hand spreading method for trenches less than 1 m wide and
machine spreading method (use a tamper spreader) for trenches more than 1 m wide.
Compaction: Select rollers or plates (such as vibrating plate compactor, vibrating
rammer, pedestrian roller, small tandem vibrating roller) to suit the size of the job. Keep
the drum or plate moist to prevent the adherence of asphalt. Complete rolling while the
mix temperature is above 95C. The relative compaction (ratio of the in situ density or
the compacted asphalt and the representative maximum density of the asphalt) must
not be less than 91%.
Surfacing course
Asphalt surfacing course: BCC type 1 mix (5 mm nominal aggregate size) or BCC type
2 mix (10 mm nominal aggregate size) or BCC type 3 mix (18 mm nominal aggregate
size) as specified. Limit the thickness of each compacted layer to 15 - 25 mm for BCC
type 1 mix and 25 - 40 mm for BCC type 2 mix, and 40 - 60 mm for BCC type 3 mix.
Permitted materials: Comply with the requirements of Table 10.3.
December 2001
21
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
Table 10.3 - Surfacing course reinstatement
Location
BCC asphalt mix Thickness
Footpaths
Type 1
25 mm or the adjacent asphalt thickness, whichever is greater
Bikepaths
Type 1 or 2
25 mm or the adjacent asphalt thickness, whichever is greater
Minor roads
Type 2
50 mm or the adjacent asphalt thickness, whichever is greater
Major roads* Type 3
75 mm or the adjacent asphalt thickness, whichever is greater
*
Where the trench runs longitudinally along the road with more than one half of the traffic lane
affected, extend asphalt resurfacing to the whole traffic lane. Provide 50 mm thick asphalt to
the remainder of cold planed surfaces.
Base course
Material selection: Choose base course material to suit the permeability characteristics
of the existing pavement base to ensure that the reinstated pavement does not hold
water nor obstruct existing drainage paths through the pavement.
Field test: Collect a handful of representative unbound pavement material, discarding
particles larger than 10 mm in diameter. Spray a fine water mist evenly throughout the
soil particles to achieve the optimum moisture content. Mould the moist sample by
hand pressure. The unbound pavement material is considered relatively impervious if
the moulded sample remains intact after being tossed lightly from one hand to the other.
The unbound pavement material is considered relatively permeable if there is difficulty
in maintaining the moulded shape or the moulded sample crumbles after being tossed
lightly from one hand to the other.
Existing permeable unbound pavement material: Typically the blue-grey fine crushed
rock material sourced from Council’s Mt Coot-tha quarry.
Existing impermeable unbound pavement material: Typically the yellow-orange or light
brown aggregates sourced from Council’s Pine Mountain quarry.
Structural asphalt: BCC type 3 mix (18 mm nominal aggregate size) or BCC type 4 mix
(35 mm nominal aggregate size). Limit the thickness of each compacted layer to 40 80 mm for BCC type 3 mix and 70 - 100 mm for BCC type 4 mix.
Class 1 unbound pavement material: Grading B or C and material properties in
accordance with S300 Quarry Products. Alternatively, this material may be substituted
with Queensland Department of Main Roads type 2 unbound material, subtype 2.1.
Achieve a minimum relative compaction of 95% of the modified maximum dry density to
AS 1289.5.2.1.
Lean mix concrete: In accordance with Clause 10.4.
Permitted materials: Comply with the requirements of Table 10.4. For isolated patches
less than 2 m2 in size, use lean mix concrete.
December 2001
22
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
Table 10.4 - Base course reinstatement
Subsoil
condition
Existing base course
Permitted material
Thickness
Reference
Permeable
Permeable unbound
pavement (gravel)
-
Class 1 unbound
pavement material
Match adjacent
base course
Figure 8.1
Impermeable
Permeable unbound
pavement (gravel)
-
Class 1 unbound
pavement material
Match adjacent
base course
Figure 8.2
Permeable
Impermeable unbound
pavement (gravel)
-
Match adjacent
base course
Figure 8.3
-
Class 1 unbound
pavement material
Structural asphalt
Lean mix concrete
Figure 8.4
Impermeable
Impermeable unbound
pavement (gravel)
-
Structural asphalt
Lean mix concrete
Match adjacent
base course
Permeable
Structural asphalt
-
Structural asphalt
Match adjacent
base course
Impermeable
Structural asphalt
-
Structural asphalt
Match adjacent
base course
AC surfacing course
AC surfacing course
Permeable
road base
-Class 1 material
Saw cut neatly
on both sides
-Class 3
-Stab. sand
-Flowable fill
-Lean mix
-Granular fill
Permeable
sub-surface
strata
Trench
backfill
Trench
backfill
Impermeable
sub-surface
strata
Figure 10.2 (Permeable road
base in impermeable subsoil)
Figure 10.1 (Permeable road
base in permeable subsoil)
AC surfacing course
AC surfacing course
-Structural asphalt
-Lean mix concrete
Impermeable
road base
-Class 3
-Stab. sand
-Flowable fill
-Lean mix
Saw cut neatly
on both sides
-Granular fill
Trench
backfill
Saw cut neatly
on both sides
Pipe/conduit surround
(bedding, haunch, side
and overlay zones)
Pipe/conduit surround
(bedding, haunch, side
and overlay zones)
-Class 1 material
-Structural asphalt
-Lean mix concrete
Permeable
road base
-Class 1 material
Permeable
sub-surface
strata
Trench
backfill
Pipe/conduit surround
(bedding, haunch, side
and overlay zones)
Figure 10.3 (Impermeable road
base in permeable subsoil)
December 2001
23
Impermeable
road base
Saw cut neatly
on both sides
Impermeable
sub-surface
strata
Pipe/conduit surround
(bedding, haunch, side
and overlay zones)
Figure 10.4 (Impermeable road
base in impermeable subsoil)
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
11.0 SERVICE CONDUIT INSTALLATION
11.1 GENERAL
Scope: This clause does not apply to the installation of a reticulated pipe network
system nor does the clause apply to the installation of conduits conveying combustible
or flammable liquids.
Alignment: Locate services within the designated corridors and provide minimum pipe
covers to comply with the relevant Standard Drawing UMS 121 and UMS 122 or
UMS 123 and UMS 124. Provide conduits that pass inspections and tests required by
the appropriate Service Authority.
Electricity conduit: Supply conduit to comply with the “Heavy Duty” requirements of
AS 2053.
Also refer to Energex publication titled Underground Distribution
Construction.
Gas conduit: Supply conduit to comply with AS 4130.
Water conduit: Supply conduit to comply with AS 1477.
Telecommunications conduit: Supply conduit to comply with AS 1477.
11.2 BORING OR JACKING
Execution: Undertake boring or jacking by specialist operators with experience in similar
works (diameter, length, ground conditions), using purpose-made equipment capable of
maintaining correct lines and levels of completed conduits. Ensure a tight fit to the
service pipe or casing.
Protective conduits, concrete encasement, ducts or enveloping pipes: Extend protective
casing a suitable distance beyond batters, table drains and kerb. Provide protective
casing to all pressurised services (such as high pressure gas, combustible fluids, water
mains and rising sewer mains); any service that conveys potentially hazardous
substances which may be damaged during construction or maintenance operations; and
in any one of the following instances:
- Where the cover provided is less than minimum requirement.
- Near the footings of a bridge or other structure.
- Near other locations where there may be a hazard.
Cased bore hole: The diameter of the bored hole must not exceed the diameter of the
pipe or service by more than 50 mm.
Uncased bore hole: The diameter of the uncased hole must not exceed 100 mm under
existing roadways.
Cavities and voids: Fill cavities and voids by pressure grouting. Fill voids between the
bored hole and the pipe or service and where required, between the service and the
enveloping casing.
December 2001
24
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
11.3 INSTALLATION
UPVC pipe systems: Conform to the installation requirements of AS 2032 except where
specified herein.
Polyethylene pipe systems: Conform to the installation requirements of AS 2033 except
where specified herein.
Bedding material: Bedding sand consisting of clean sharp washed river sand or 5 7 mm nominal size screenings (recycled concrete or clean crushed rock) free of salt,
clay or organic contaminants. Comply with Table 11.1 for grading requirements.
Pipe support: Use identical bedding material for pipe underlay, side support and
overlay. Place pipe on a minimum 75 mm thick compacted underlay. Extend bedding
material to provide a minimum cover of 150 mm over the conduit.
Draw rope: Provide a 4 mm diameter synthetic polypropylene filament rope. Install
draw ropes with a minimum of 1.5 m of slack in each pit and rope ends firmly secured to
prevent the ends being lost in the conduit. Provide joints in the rope capable of resisting
the same tensile load as the unjointed rope and that do not appreciably increase the
diameter of the rope.
End plugs: Plug or cap the ends of all conduits with suitable fittings to prevent the entry
of foreign matter.
Table 11.1 - Grading of bedding material
A.S. sieve (mm)
Percentage passing by weight
Bedding sand
5 - 7 mm screenings
9.50
100
6.70
85 - 100
4.75
100
30 - 85
2.36
80 - 100
0 - 30
1.18
0.075
0-5
0 - 15
11.4 MARKING SERVICES
Temporary markers: Provide clearly labelled 50 mm x 50 mm stakes directly above the
ends of each conduit run.
Underground marking tape: Provide buried marking tape to all public utility services in
accordance with the requirements of AS/NZS 2648.
Brass marker discs: Install brass marker discs embossed with the relevant symbols at
the kerb and channel to indicate location of conduit crossings. In location where there is
no kerb and channel, construct 225 mm wide x 450 mm long x 75 mm thick grade N25
concrete block, with indentation for the indicator disc to be centrally placed on the top
face of each block.
11.5 TESTING
Time: Test all conduits after completion of subgrade preparation and before
commencement of pavement construction.
Test: A circular plug with a diameter 8 mm less than the internal diameter of the conduit,
must be able to be drawn freely through the conduit.
December 2001
25
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
12.0 GEOTEXTILES
General
Testing: To AS 3706.
Base materials: Polyamide, polyolefines, polyester and polyvinyl materials, either singly
or in combination.
Filament properties: Rot-proof, chemically stable and with low water absorbency. Nonwoven geotextiles must have the filaments bonded by needle punching, heat or
chemical bonding processes. Woven geotextiles must have the filaments interlaced in
two sets, mutually at right angles. One set must be parallel to the longitudinal direction
of the geotextile.
Ultraviolet radiation resistance
Exposed conditions: For use such as silt fence, retain 90% of its original strength after
three months exposure to sunlight.
Unexposed conditions: Retain 90% of its original strength after one month exposure to
sunlight.
Applications
Type 1, non woven: Material properties to comply with Table 12.1. Suitable for filter
drain in granular soils subject to light compactive equipment. Limit the maximum
aggregate size in contact with the geotextile to 37.5 mm.
Type 2, non woven: Material properties to comply with Table 12.1. Suitable for filter
drain for side drains in roadwork and general non-roadwork applications. Limit the
maximum aggregate size in contact with the geotextile to 75 mm.
Type 3, non woven: Material properties to comply with Table 12.1. Suitable for general
use in roadwork (other than side drains), crib walls, and gabions. Limit the maximum
aggregate size in contact with the geotextile to 200 mm.
Type 4, non woven: Material properties to comply with Table 12.1. Suitable for scour
protection works, where the maximum rock size exceeds 200 mm.
Table 12.1 - Material properties
Wide Strip
Tensile
Strength
5 percentile
value (kN/m)
Trapezoidal
Tear Strength
5 percentile
value (N)
G Rating
(Note)
Pore Size
EOS (m)
Permittivity
(s-1)
Type 1, non woven
 5.0
 180
 1000
 250
 1.00
Type 2, non woven
 9.0
 270
 2000
 180
 1.00
Type 3, non woven
 13.0
 360
 3000
 180
 1.00
Type 4, non woven
Note:
 20.0
 550
 5000
 160
 1.00
Designation/type
G Rating =
H50 =
L=
Geotextile Strength Rating = (H50 x L)0.5
Normalised drop height (mm), as determined using the Drop Cone Test procedure
in AS 3706.5
Plunger failure load (N), as determined using the CBR Plunger Test procedure in
AS 3706.4.
December 2001
26
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
Filter tube: Non woven or woven geotextile suitable for sump protection boom.
Minimum weight 285 g/m2, pore size EOS < 75 m, permittivity > 0.2 s-1.
Silt fence: Non woven or woven geotextile. G rating > 2500, wide strip tensile strength
(5 percentile value) > 4 kN/m, permittivity > 0.2 s-1.
Storage
Store geotextile under protective cover or wrapped with a waterproof and ultraviolet
protective sheering. Do not store geotextile directly on the ground or expose them to
excessive heat.
Preparation
Before placing geotextile, trim the ground to a smooth surface free from cavities and
projecting rocks.
Placing
Fixing: Lay the material flat, but not stretched tight, and secure it with anchor pins.
Overlap joints at 300 mm minimum.
Traffic: Do not allow vehicles and construction equipment on the geotextile until it has
been covered with a layer of fill or pavement material at least 150 mm thick.
Sunlight: Do not expose the material to sunlight for more than 14 days.
13.0 GABIONS AND MATTRESSES
13.1 MATERIALS
Wire, gabions and mattresses
General: Comply with AS 2423. Galvanise all wire to AS 4534. Coat all components
with polyvinyl chloride to a minimum thickness of 0.5 mm.
Gabions: Use mesh with a wire diameter not less than 2 mm. Provide appropriate mesh
size to retain the rock filling. Provide selvedge wires with a diameter not less the
3.15 mm and binding wire with a diameter not less than 2.5 mm.
Mattress: Use mesh with a wire diameter not less than 2 mm. Provide appropriate
mesh size to retain the rock filling. Provide selvedge wires with a diameter not less than
2.5 mm and binding wire with a diameter not less than 1.6 mm.
Rock fill
General: Clean, hard, durable crushed rock, rock spalls or river gravel, with minimum
size larger than the maximum opening size of the mesh or fabric forming the basket.
Rocks must be cubical where possible. The smallest dimension must not be less than
half the greatest dimension.
Properties: Wet/dry strength variation tested in accordance with QDMR Q205C or
AS 1141.22 must not exceed 35%. Ten percent fines value tested in accordance with
QDMR Q205B or AS 1141.22 must not be less than 140 kN.
Gabions: Provide rock of nominal size between 120 mm and 200 mm. Rock must be
uniformly graded, with greater than 80% by number exceeding the 150 mm nominal
size.
Mattresses: Provide rock of nominal size between 75 mm and 150 mm. Rock must be
uniformly graded, with greater than 80% by number exceeding the 100 mm nominal
size.
December 2001
27
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
Anchor plates, bolts and pickets (mattresses)
Anchor plates: Grade 250 steel to AS 1594. Smooth all sharp edges and curves prior to
galvanising. Galvanise to comply with AS 4680 after fabrication.
Anchor bolts: Supply hot dip galvanised anchor bolts to secure the anchor plates to the
concrete.
Anchor pickets: Supply star pickets 1.8 m long.
13.2 EXECUTION
Gabions
General: Construct gabion protection work in the locations and in accordance with the
details shown on the drawings.
Surface preparation: Trim areas on which gabions are to be positioned to the specified
shapes within a tolerance of  50 mm. Trimmed surfaces must be free of roots, stumps,
brush, rocks and the like protrusions.
Geotextile fabric: Place type 3 geotextile behind all gabions.
Assembly: Assemble to comply with the drawings and recommendations of the
manufacturer.
Positioning: Position assembled gabions empty in the works. Securely position the first
row of gabions and fill before gabions in other rows are positioned.
Rock fill: Hand pack the exposed faces of the basket. The remainder may be filled
using machine methods. Place the rock to produce a dense, evenly distributed filling
with a minimum of voids. Maintain the tolerances and shape specified. Tie together the
outer and inner panels of the gabions during the placing operation to minimise
distortions where necessary.
Damage: During the placing, do not damage the gabion mesh or geotextile.
Mattresses
General: Construct mattress protection work in the locations and in accordance with the
details shown on the drawings.
Surface preparation: Trim areas on which gabions are to be positioned to the specified
shapes within a tolerance of + 50 mm to – 50 mm, except where the provision of such
tolerances will not permit the tops of the mattresses to join neatly to the inverts of
adjacent culverts. Trimmed surfaces must be free of roots, stumps, brush, rocks and
the like protrusions.
Geotextile fabric: Place type 3 geotextile behind all mattresses.
Assembly: Assemble to comply with the drawings and recommendations of the
manufacturer.
Positioning: Position assembled mattresses empty in the works. Fix the upstream edge
(if any) and the top edge of each mattress using star pickets at 1 m centres. Make
neatly cut openings for the pickets in the geotextile. Drive pickets to refusal or full
depth. Finish the pickets level with the tops of the mattresses.
December 2001
28
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
Rock fill: Fill each row of mattresses before following rows are placed. Tension the
mattresses before filling. Place fill to produce a dense evenly distributed filling with
minimum voids and distortion of the mattress shape. Release tension on the mattress
when the mattress has sufficient rock filling to prevent the mesh from slacking after
release.
Damage: During the placing, do not damage the mattress or any geotextile under the
mattresses.
Construction tolerances
General: Construct gabions and mattresses in the locations and in accordance with the
details shown on the Drawings.
14.0 ROCK SCOUR PROTECTION
Application
Ungrouted rock lining to provide scour protection to open channels and other areas as
specified. Refer annexure.
Rock
Use clean, hard, durable, well graded rock spalls with a nominal size of 200 mm or
more. At least 50% of rocks must be larger than a size twice the specified nominal size.
Wet/dry strength variation tested in accordance with QDMR Q205C or AS 1141.22 must
not exceed 35%. Ten percent fines value tested in accordance with QDMR Q205B or
AS 1141.22 must not be less than 140 kN. The breadth and thickness of a single stone
must not less than one-third its length. Refer annexure.
Thickness
The thickness of the rock facing must be at least twice the nominal rock size. Refer
annexure.
Excavation
Excavate the area to be rock faced so the final rock surface finishes level with the
surrounding ground level.
Placing
Minimise the chances of rocks running loose and damaging adjacent areas. Recover
any rocks deposited outside the rock protection zone. Place rocks in a manner that
ensures that the larger rocks are uniformly distributed throughout the protection works,
and that the smaller rocks effectively fill the spaces between the large rocks without
leaving any large voids. Layers of placed rock must have even thickness and even
grading.
Geotextile
Install type 4 geotextile over the area to be rock-faced. Place rock to avoid damage to
the geotextile.
December 2001
29
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
15.0 ROCK FILLING
Application
Rock filling to provide low settlement at structures and other areas as specified.
Rock
Use clean, hard, durable, well graded rock spalls with a nominal size of 200 mm.
Wet/dry strength variation tested in accordance with QDMR Q205C or AS 1141.22 must
not exceed 35%. Ten percent fines value tested in accordance with QDMR Q205B or
AS 1141.22 must not be less than 140 kN. Rocks of length greater than 100 mm must
have breadth and thickness not less than one-third of the length.
Placing
Layering: Place rock in layers no deeper than 750 mm. Construct layers horizontally.
At structures, avoid differences in surface levels that would cause horizontal loading on
the structure.
Exposed faces: Hand pack all exposed faces with selected aggregate. Place the rocks
with their greatest dimension perpendicular to the face, breaking the joints vertically.
Compaction
General: During the placing of the rock, continuously sluice with water pumped from a
50 mm pump through a 50 mm hose and nozzle and compact with a vibrating roller of
static weight 5 tonnes to ensure rock to rock contact throughout.
Confined spaces: Where the use of a 5 tonne roller is impracticable, use a 1 tonne
vibratory roller or, if necessary, a mechanical rammer.
16.0 BARRIERS AND MEMBRANES
Protective covering: Do not disturb or damage the protective covering of membranes
during backfilling.
17.0 RETAINING WALLS
17.1 CRIB WALLS
Proprietary system of interlocking precast concrete or preservative treated timber cribs
with backfill as specified by the manufacturer, placed and compacted progressively with
the crib to form a retaining wall. Refer annexure.
December 2001
30
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
17.2 EARTH REINFORCEMENT
Scope
Reinforced soil structures consisting of proprietary systems of reinforcing strips placed
in layers with compacted select fill and connected to precast concrete facing panels to
form vertical retaining walls. Refer annexure.
Design
Standard: To Queensland Department of Main Roads standard specification MRS11.06
Reinforced Soil Structures.
Design life: 120 years. Refer annexure.
Wall movement: The maximum long term incremental lateral deflection of any part of
the wall facing, occurring at any time, must not exceed 20 mm. Refer annexure.
Facing units: Concrete Grade N32 to AS 3600 with surface finish to Class 2 to comply
with AS 3610.
Fill
Comply with Queensland Department of Main Roads standard specification MRS11.06
Reinforced Soil Structures.
Accessories
Provide the necessary accessories including levelling pad, bearing pads and joint fillers
or covers to keep the fill material out of the panel joints. Refer annexure.
Construction
Comply with Queensland Department of Main Roads standard specification MRS11.06
Reinforced Soil Structures.
Completion
Provide as constructed drawings, including sections at 5 m centres.
December 2001
31
Urban Management Division
Reference Specifications for Civil Engineering Work
S140 Earthworks
18.0 GROUND ANCHORS
18.1 GENERAL
Application: Permanent or temporary ground anchors, placed in any aspect, which use
a prestressing tendon anchored in rock or soil at one end and stressed at the other end.
Refer annexure.
Materials and design: To AS 3600.
18.2 EXECUTION
Soft ground
Temporarily line holes in soft or loose ground to prevent collapse. Do not use wrapped
tendons.
Stressing
Stress each anchor to a test load of 85% of the ultimate strength of the tendon, hold for
a minimum of five minutes, and then reduce the stress to the lock-off load. If the anchor
fails to maintain the load for five minutes, replace it. Refer annexure.
Tendon protection
Grout the free length of tendon inside sheath of permanent anchors as soon as possible
after they have been stressed.
Protection of stressing anchorages
Protect the stressing anchorage of permanent anchors by filling the anchorage blockout with concrete after final stressing. Trim tendons to give a cover of 50 mm. If no
block-out is provided, construct concrete protection to give a minimum cover of 50 mm
to all steel components.
Temporary anchors
De-stress tendons and remove wedges on completion of use of the anchor.
Completion
Provide as constructed drawings showing the lock-off load, position, direction and
length of permanent ground anchors.
December 2001
32