Elastoplastic analysis of the seismic response of tunnels in soft soils

This paper presents an elastoplastic finite element analysis of the seismic response of tunnels constructed in soft soils. The behavior of the soil material is described using a cyclic elastoplastic constitutive relation involving both isotropic and kinematic hardening. The paper is composed of three parts. The first part includes a brief presentation of the numerical model used in the analysis; the second one concerns analysis of the seismic response of a tunnel constructed in a soft soil; the last one presents a study of the influence of the plasticity and soil dilatancy on the seismic response of tunnels. Analyzes show that the plastic deformations induce an important reduction in the seismic-induced bending moment in the tunnel, while the soil dilatancy moderately affects the bending moment in the liner.