Three-dimensional nonlinear response of utility tunnels under single and multiple earthquakes

Abstract The behavior of utility lined tunnels under single and multiple earthquakes is studied under the assumptions of inelastic material behavior of the liner and the rock medium and full three-dimensionality. Inelasticity in both media is modeled by the theory of damage mechanics. The seismic response of the rock-structure-fluid system is parametrically studied in order to assess the degree of influence of the various parameters on that response. These parameters are material parameters, such as Poisson's ratio of concrete liner and rock, geometrical parameters, like depth of the tunnel from the ground surface or the liner thickness, seismic load parameters, like seismic intensity, multiplicity of earthquakes and seismic incident angle, and interaction parameters, like rock-structure interaction and fluid-structure interaction. Thus, the seismic response of utility tunnels, as influenced by the above parameters, is assessed and useful conclusions are drawn.