Development and Verification of a Pseudo-Static Solution for Evaluation of Seismic-Induced Deformations of Rectangular Tunnels

An iterative procedure is proposed to estimate seismic-induced distortions in cut and cover rectangular structures. The procedure is based on an existing analytical solution for deep rectangular structures. The existing solution assumes elastic behavior of soil and structure, tied contact at soil-structure interface, and static loading. The new procedure builds on the analytical solution and approximates dynamic response with a pseudo-static analysis, and soil-stiffness degradation through an iterative procedure where the soil's shear modulus is changed in each iteration based on the shear strain of the soil obtained in the previous iteration. Predictions obtained from the analytical solution have been verified by a series of numerical tests which include the response of. the Daikai station during the 1995 Kobe earthquake. The relative errors in terms of deformation between analytical and numerical results are less than 15%.