Design and construction of retaining structures for Lane Cove tunnel

Paul Hewitt, Stephen Burkitt and Bas Baskaran

The Lane Cove Tunnel in Sydney connects the M2 Motorway at North Ryde with the Gore Hill Freeway and the Pacific Highway at Artarmon. Design and construction involved about 70 retaining structures which included braced and anchored bored pile walls, soil nailing, reinforced soil wall systems and post-tensioned cantilever walls. Significant challenges related to restricted site access, the need to minimise construction impacts and a tight design schedule.

Rigorous assessment of the effects of new construction on existing structures and construction safety utilised advanced numerical techniques to model ground-structure interaction. This paper discusses various geotechnical issues affecting design and construction, how the design was implemented in the field and documents results of performance monitoring.