DYNAMICAL ANALYSIS OF A SATURATED SOIL-LINING SYSTEM WITH A DEEPLY BURIED CIRCULAR TUNNEL SUBJIECTED TO A BLAST LOAD

Considering the reflection and the effect of suction pressure of explosion wave on inner lining, and assuming the lining as the elastic medium, the axisymmetrical transient dynamic responses of a saturated soil-elastic lining coupled system with a deep tunnel, subjected to a blast loading, are investigated. First, based on the Biot theory and the elasticity, under the boundary conditions as well as the continuity conditions on the interface between the saturated soil and elastic lining, analytical expressions of the displacements and stresses of the saturated soil and elastic lining as well as the pore water pressure expression in the Laplace transformed domain are derived by means of the Laplace transform. Then the dynamical responses in the time domain of the saturated soil are obtained using the numerical inverse Laplace transform. The influences of the different tunnel models and different blast loading models on the dynamical responses of the saturated soil are numerically examined, and parameter studies are conducted. It is revealed that the effect of the suction pressure due to the explosion wave reflection on the dynamical responses of the saturated soil is significant. Furthermore, the response of the saturated soil-shell lining system, saturated soil-elastic lining system and saturated soil without lining are almost the same, but the periods and amplitudes of the responses are different.