3-Dimensional Numerical Modelling of a Deep Basement Excavation Adjacent to Rail Tunnels and Geological Fault Zone in Sydney CBD

摘要

A geotechnical 3-dimensional analysis was undertaken to assess the impacts of a proposed basement excavation and ground loadings for a retail and commercial redevelopment site in Sydney CBD on existing rail tunnels. There is a known presence of a geological fault zone and an area of additional jointing parallel to the fault zone which traverses the site. The design of the retention system for the excavation boundary was not finalised and therefore reasonable assumptions of the behaviour of the retention system had to be made. Geotechnical analysis was carried out to assess the changes in rail tunnel stresses and likely deformation induced by the proposed redevelopment. The analysis assesses the potential impacts of the relief of relatively high in-situ horizontal locked in stresses in the Hawkesbury Sandstone and the lateral movements of the excavated faces on the tunnel behaviour.