A 2.5D equivalent linear model for longitudinal seismic analysis of tunnels in water-saturated poroelastic half-space

This paper provides an efficient and rigorous model for 3D seismic analysis of long lined tunnels considering wave passage effects. By taking advantages of the 2.5D model, computation effort is considerably reduced. The water-saturated poroelastic half-space is modelled as two-phase media and soil nonlinearity is considered via the equivalent linear approach. This improved model is realized by a finite element-indirect boundary element (FEIBE) coupling method. The study reveals that the wave passage effect causes significant longitudinal deformation of the tunnel, and differences in the tunnel seismic responses between the two-phase half-space case and the single-phase half-space case are not negligible.