Numerical modeling of a nonlinear deformational behavior of a tunnel with shallow depth

A new finite element analysis procedure is proposed for simulation of deformational behavior around a shallow tunnel. The method incorporates reduction of shear stiffness, as well as strain softening effects of a given material. An illustrative example is shown in which the proposed method is applied to simulate an excavation process of a tunnel made of aluminum bars, Results obtained indicated that surface settlement, ground reaction curve, minimum supporting pressure, and formation of kinematic collapse are in good agreement with experimental results. The typical deformational mechanism observed in the experiment is also seen in the field, which is hopefully modeled with accuracy by the proposed numerical procedure.