The Wambo Rail Spur located near Singleton, New South Wales, Australia, runs
for approximately 14 km linking the Mt Thorley rail loop and the Wambo Coal
Mine. The project involves a 260 m long tunnel in weathered sedimentary and
intrusive materials. The tunnel has a low cover and runs under a main
This second paper on the project looks into one aspect of the tunnel in
detail: the use of shotcrete arch as the primary support for part of the tunnel
excavation. The use of shotcrete instead of steel arch, formulation of the
material specification, construction sequencing, installation at the excavated
face and material testing for verification related to this facet of the project
will be discussed in this paper.
The tunnel opened in April 2006, and two years on, we briefly reflect on the
impact of this design decision on the overall project.