Numerical methods for innovative seismic design and analysis of tunnel structures located in highly active seismic zones

摘要

This paper presents the state-of-the art and practice for "innovative" seismic design and analyses of the Tunnel structures located in a highly active seismic zone. Seismic hazard and seismic design criteria applicable to various types of tunnel structures are discussed. Implementation of the Response-Spectrum-Compatible Ground Motion time histories and nonlinear finite element method are used for the analysis and design of the tunnels. A two-step analysis procedure has been adopted to assess the performance of the tunnels liner subjected to a design earthquake. The first step is to compute seismic induced deformations of the tunnels without the presence of the liner due to seismic wave propagation through the rock and or soil medium. The second step involves imposing the free-field deformations of the tunnel onto the structural liner through springs which accounted for interaction between the liner and surrounding medium. The objective of the analysis is to estimate the responses of final lining configurations of the tunnels due to seismic excitations. Seismic analysis and design of tunnel linings using ovaling and or racking deformations as a result of seismic wave scattering mechanism that would lead to different modes of distortion on the tunnel cavity will be discussed.