Building Around Tunnels - Case Histories
Abstract
This paper describes case studies of building developments around tunnels. The case studies highlight a number of fundamental issues that have to be addressed when assessing the potential interaction between building construction around existing tunnels.
Apart from safety, the over riding concern is the potential impact that the building excavation and imposed building loads will have on the adjacent underground structure and in particular the tunnel lining. In the case of rock, potential sliding along defects in deep basement excavations (as this may also affect the rock modulus properties assumed in the analysis, typically reported in Sydney's sandstone).
The commercial drivers for these building developments with deep basements, generally, is the need to maximise site utilisation where building height limits are imposed and also to minimise delays during the building approval process.
Basement excavation for buildings can induce unacceptably high stresses in tunnel linings and building foundation loads may have to be transferred below the tunnel to eliminate potential loading impacts on the integrity of the underground structure.
Author
Ted Nye