Subsidance monitoring, Hume Highway, NSW, Australia
The NSW Government granted permission to BHP Billiton to extract coal by longwall mining at their Appin West Colliery. The longwalls extend beneath the Hume Highway and Main Southern Railway, north-east of Douglas Park. The highway carries more than 37,000 vehicles a day at speeds up to 110 km/h. The Main Southern Railway carries XPT services at 125 km/h as well as local trains. Some areas of the highway are expected to subside by up to 1.5 m.
PSM was engaged to assess and monitor potential movement along geotechnical structures, closure slots within the Hume Highway pavement and joint monitors on the Douglas Park Bridge.
engineering and technical OPPORTUNITIES
The impact and scale of potential disruptions attracted a high level of public interest of this main road infrastructure between Sydney and Melbourne.
Engineering and technical opportunities included:
- Minimising the impact to the road’s function
- Minimising impact on Main Southern Railway line due to mining
- Protecting the Douglas Park twin bridges which form part of the highway
- Calibrating the degree of subsidence using a scale of injury and fatality.
approach AND innovation
Following a rigorous site investigation and ground model development, PSM’s innovations included:
- Development and installation of early warning systems, including an in-place inclinometer, to continuously monitor subsidence
- Development of a new method of accommodating subsidence within the road pavement without disrupting traffic flow
- As part of a team, development of an innovative approach for real time in pavement monitoring that includes remote access to a series of 400 sensors collecting deformation data 24 hours a day.
Premier’s Award 2011
Successful development of an award-winning tailored monitoring system which fulfilled the client’s requirements.