Elastic-slip interface effect on dynamic response of underwater convey tunnel in saturated poroelastic soil subjected to plane waves

In engineering construction, the elastic-slip interface often exists around the tunnel. An elastic-slip interface model is proposed to analyze the dynamic response of underwater convey tunnel, and the surrounding soil is assumed to be saturated poroelastic medium. The reflected, refracted and scattered waves in the free surface water, the surrounding soil medium and the tunnel are expressed by wave function expansion method. Based on Biot's dynamic theory, an elastic-slip interface is developed to analyze the scattering of P and SV waves around the tunnel. The interface coefficients (normal and tangential spring coefficients and slip coefficient) are introduced to analyze the elastic-slip interface effect on the dynamic stresses under different wave frequencies. It can be concluded that the effect of normal spring coefficient is greater than that of tangential spring coefficients. The interface effect in the region of low frequency is greater than that of high frequency. The interface effect under different surface water depths and embedded depths of tunnel is also examined. Comparison with existing numerical results validates this dynamic model.