Transient dynamic response of tunnels subjected to blast loads in saturated soil

Using an analytical method, the dynamic response of a circular tunnel in the saturated soil is investigated. Assuming that the blast occurs in the center of the tunnel, a model is established using simplified blast loads. The motions of the liner are considered specially based on the Flügge theory. The Biot’s theory is used to describe the saturated soil. By introducing two potential functions, the analytical solutions of displacement and hoop stress induced by the blast loads are derived in Laplace transforms domain．Numerical results are obtained by inversion of Laplace transforms presented. The influences of permeable property of interface between the liner and soil on dynamic response of the tunnel are analyzed. Also, the influences of the parameters of the saturated soil and the relative rigidity of the liner are discussed. It is shown that the maximum stresses and displacements are both higher under impermeable conditions than those under permeable conditions. The parameter
has a significant effect on the amplitude of hoop stress. What’s more, the attenuation of the responses becomes more apparent as the rigidity of liner increases.