scope:

Mitigation of earthworks covers:

a) operational restrictions

b) temporary restraints

c) geotechnical instrumentation array (GIA) systems

d) alert/alarm systems.

This document does not cover the:

a) process for mitigation where an earthwork failure has resulted in the loss of track support or track geometry or loss of kinematic envelope

b) health and safety requirements applicable to operational safety

c) permanent installation of physical barriers and restraints or emergency works (other than the use of temporary restraints).

NOTE; Refer to NR/L3/CIV/071, and NR/L2/CIV/086/Mod04, for the implementation of permanent earthwork restraints (such as catch fences, catch netting, catch ditches, catch walls and avalanche shelters).

Purpose

Earthwork mitigations are measures carried out on or near an earthwork asset that do not change the likelihood that the asset might fail, but that manage the consequences of failure and hence reduce the overall earthwork safety risk.

This process outlines the procedures that manage the earthwork mitigation measures/controls, mitigating the risks of geotechnical slope failure leading to loss of kinematic envelope or track geometry.