Abstract:

The construction of buildings (structures) above existing tunnels will not only cause settlement or uplift of the tunnel，but also repeated changes in the load will cause cracking of the tunnel lining. Therefore, in the design and construction of the buildings (structures), rational measures should be taken to avoid or minimize the influence on the existing tunnels below. The extension line of a highway is designed to overcross an existing tunnel, for which three overcrossing options, i.e., overcrossing by means of rigid board, overcrossing by means of bridge and overcrossing by means of subgrade, are proposed. Comparison and contrast is made among the mentioned three overcrossing options, which shows that the option of overcrossing by means of rigid board has such advantages as being cost efficient and easy to be implemented. The implementation of overcrossing by means of rigid board is verified by means of numerical simulation. It is the first time in China that rigid board is adopted to overcross existing tunnel. The design of the works described can provide reference for similar works in the future.

Key words: existing tunnel, highway, settlement, rigid board, finite element