Deformation stability analysis of foundation of Taijiao high-speed railway above the mined-out area affected by rainfall

Aiming to the requirements of potential safety risk control along the high-speed railway, taking the foundation of Taijiao high-speed railway above the mined-out area of Dianshang, China as the engineering background, a mechanical model of composite rock strata of the foundation was established based on the theory of thin plate. Combined with the catastrophe theory, the evaluation system of the foundation stability was constructed. Using the selfdeveloped similar model test and rainfall device, the deformation stability of the foundation under the condition of heavy rainfall and dynamic loading of the high-speed railway was analyzed. Results show that the maximum influence depth of the dynamic loading and heavy rainfall on the foundation is about 20 m, and the further compaction of the foundation cracks is the main factor leading to the subsidence of the foundation above the mined-out area. In addition, the increase of the number of longitudinal tensile cracks in the foundation, which gradually plays a dominant role in the new cracks, shows an exponential growth trend. Being affected by the continuous heavy rainfall, the deformation evolution of the foundation displays four stages: the initial stabilization, the slow deformation, the first sudden-jump, and the secondary sudden-jump stages. Among them, the surface's maximum deformation occurs in the secondary sudden jump stage. The conclusions obtained in this study provide a theoretical basis for the stability evaluation and treatment of the foundation of the high-speed railway above the mined-out area.