Study on Stability of Long and Deep Foundation Pit of Railway under Rainfall

In this study, the influence of rainfall conditions on the stability of foundation pit and the mechanical behavior of supporting structure was analyzed by numerical simulation. The results show that dewatering excavation can reduce the pore water pressure of soil by lowering the groundwater level, and effectively restrain the deformation of supporting structure and surface settlement. Heavy rainfall (such as once-in-a-decade and once-in-a-century rainfall) significantly aggravates the surface settlement and deformation of supporting structures, especially the deep supporting structures. With the increase of rainfall intensity, the mechanical properties of soil tend to be stable after saturation, and the increase of settlement and deformation gradually slows down. The research shows that dewatering excavation and reasonable support design can effectively improve the stability of foundation pit under complex hydrological conditions, which provides theoretical support for engineering practice.