An approach for ground risk management during construction of road tunnels in New South Wales.

Risks related to the ground are generally regarded as critical technical risks on tunnelling projects. In the context of this paper, ground related risks cover geotechnical, hydrogeological, and environmental risks related to the ground. Transportation related tunnelling projects in New South Wales are generally procured with contracts that assign all ground related risk to the contractor. In more recent times, instances of incentivised target cost procurement models, where risk allocation is more generally shared, have been utilised. However, within the contractor's team, it is often not clear who owns ground related risk. For instance, is the risk related to a design issue or a construction issue; and where there are numerous designers used on projects, which designer is responsible for managing a particular risk? Recent litigation (NSWSC, 2016) and prosecutions (ICNSW 2009a, 2009b, IRCNSW 2012a, 2012b, 2012c) have identified a lack of clarity as to how ground related risk has been managed on projects. This lack of clarity has resulted in significant incidents from which lessons should be learned and applied. This paper discusses an approach applied to the management of ground related risk on road tunnels in New South Wales. The approach includes identification of all credible ground related hazards that are assessed as project risks with mitigation strategies identified for risks that could impact the project or third-party infrastructure. The approach also requires the workflow associated with ground related construction processes from data collection through to data validation to be identified; and accountabilities and responsibilities assigned for each stage in the workflow. [ABSTRACT FROM AUTHOR]