Table 5.1 – Minimum cover requirements
-
Location of service
|
Minimum cover
|
Major Road Pavements
|
1200 mm
|
Minor Road Pavements
|
750 mm
|
Road verges, footpaths, bikeways
|
600 mm
|
All other areas
|
600 mm
|
Support of adjacent construction
Shoring of trench and excavation: Where required, erect and maintain shoring to prevent trench collapse or to provide supports to adjacent structures, 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.
If permanent supports for adjacent structures are necessary and are not described, give notice and obtain instructions.
Obstructions
Remove sharp projections from trenches. Remove other obstructions including stumps and boulders, which may interfere with services or bedding.
Before cutting back roots of street trees encountered in trenches to be clear of services, notify Council’s arboriculture officer.
Where the service trench passes between existing street trees and the road pavement, install Nylex Root Barrier, or approved equivalent, minimum of 600 mm depth to the tree side of the trench in accordance with Standard Drawing BSD-9082.
Dewatering
Keep trenches free of water. Place bedding material, services and backfilling on firm ground free of surface water.
Where surrounding material becomes saturated during excavation e.g. emergency repairs to water and sewerage services, remove saturated material surrounding the excavation to expose dry, stable material and replace with trench backfill in accordance with this Specification.
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.
Non-rippable Material
Where the methods of measurement require differentiation of non-rippable material, refer to Reference Specification S140 Earthworks.
Explosives
Do not use explosives.
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