Influence of tectonic stress on the structural safety of mountain tunnel under the strike-slip faulting

The distribution of tectonic stress around the fault is very complicated, which may affect tunnel behavior under the dislocation of fault. Therefore, this paper aims to investigate the influence of tectonic stress on the structural safety of mountain tunnel under the strike-slip faulting. Variable lateral stress coefficients from 0.3 to 3.0 are considered via a series of three-dimensional finite element models. Safety assessment indices based on the overall lining damage in compression/tension and the ovalization of the tunnel cross-section are used to evaluate the damage of tunnel structure subjected to fault movement quantitatively. The results show that the cross-sectional damage and ovalization of tunnel lining mainly distribute around the fault plane, and the tectonic stress plays a crucial role in the tunnel's response to strike-slip faulting. With the increasing lateral pressure coefficient, both the value and distribution scope of the cross-sectional compressive damage in the longitudinal direction increase; while the value and distribution of cross-sectional tensile damage decrease when the coefficient is larger than 1.0, and its damage is slighter than compressive damage. The cross-sectional ovalization of the tunnel is also significantly affected by the lateral pressure coefficient, especially when the coefficient is larger than 1.0.