Three-dimensional dynamic response of a lined tunnel in a half-space of saturated soil under internal explosive loading

Blast waves have a random direction of propagation with reference to the axis of the tunnel and this renders the problem three-dimensional. Because tunnels are buried in a certain depth, a half-space model is more appropriate than a full space model in the dynamic analysis. In this paper, three-dimensional (3D) dynamic response of a lined tunnel buried in a half-space of soil due to blasting is studied analytically. The lining structure and the surrounding soil are treated as a homogeneous elastic medium and a saturated porous medium, respectively. The 3D solutions for displacement, stress and pore water pressure in the saturated soil and the displacement at the ground surface are derived in time domain by means of the Fourier and Laplace transforms. The effects of buried depth to these various dynamic responses are investigated numerically.