06/1168 - Change a Development Approval [As Published] · 132006.1168.02

=

Subsoil drains of the type specified or as directed by the Superintendent shail be installed at same grade
as kerb and channel.

Unless specified otherwise, subsoil drainage trenches shall incorporate geotextile material lining the
trench. in areas where the natural soil could cause blockage of the geotextile material and the ultimate
failure of the Pavement Subsoil Drainage system, the Superintendent may advise the following if
applicable:

» Whether the trench shall incorporate geotextile material.

» What type of alternative subsoil drainage backfill material (in accordance with this specification) shall
be used.

» Whether the spacing of the subsoil drainage clean out points can be decreased from the specified
requirements.

Subsoil Drainage clean outs shall be constructed in accordance with the construction drawings provided,
and shall preferably be located with the upstream flushing point internally within a stormwater gully pit or
manhole. The maximum spacing of subsoil drainage clean outs shall be not greater than 50 metres
apart.

No construction equipment shall stand or travel! directly on subsoil drain material or constructed drains
without approval.

Payment shall be made at the rate shown in the Schedule for the actual length installed.

Minimum cover for various compacters over the drain shall be unless approved otherwise:

Hand Held Units - 100 mm
Units <15 Tonnes - 200 mm
Units >15 Tonnes - 300 mm

4.2.2 Material Requirements

Trench backfill material shall be crushed or granular material that conforms to the grading requirements
shown below:

 

 

 

 

 

 

 

 

 

 

 

AS Sieve Size (mm) | Percentage Passing by Mass
19.0 85-100
9.5 0-20
4.75 0-5
1.18 :
0.30 -
0.15 -
41/22382/11840 Girraween Sports Precinct 26

Earthworks Package