Crossing of the M1 Freeway at Wyong, NSW

The original bore design was flagged by the client due to concerns with safe depth under road and size of required bore hole, ground conditions to be encountered and the safety and practicality of crossing the existing 500mm high pressure gas trunk main and a 300mm Caltex petrol pipeline.

Original bore was designed to included a 750mm casing pipe to house a 450mm water main which would then require a borehole of approx. 950mm. This design had the pipeline above the rock shelve and within close proximatey to the road surface (2-3m) placing a high risk of Frac-out and or bore hole collapse during its construction.

After a detailed review of the project including geotechnical and existing services, Trenchless Advisors re-design the bore placing it approx. 8m below the surface of the road and within the sandstone ground conditions. As the bore was now within the rock, a casing was not required (after the confirmation of a settlement analysis) so the casing was eliminated requiring a smaller bore hole of approx. 550-600mm. A safe boring clearnace was placed around the existing petrol and gas pipelines as well as a suitable and achievable bend radius.