Cumulative Deformation Analysis of Foundation of Mined-Out Areas under Dynamic Loading- a Case Study of Taijiao High-Speed Railway

Since there is a safety risk of cumulative deformation exceeding the limit when high-speed rail passes through the mined-out areas, for the special needs of risk control along the high-speed railway, taking the foundation of the mined-out areas of Dianshang coal mine under Taijiao high-speed railway as the background, the mechanical model of rotation structure of key block was established. The stability criterion of fracture structure rock of the mined-out area was proposed. Using self-developed similar model test and dynamic loading device, the evolution characteristics and deformation mechanism of foundation of the mined-out areas under long-term dynamic loading of the high-speed railway were analyzed. Results show that when the number of loading vibration exceeds 5 million times, the foundation of the mined-out areas will occur over all settlement and deformation. The cumulative deformation of the foundation in different buried depths has similar variation law with the increasing of excitation and all experience three stages: the slow growth stage, the fast growth stage, and the stable stage. The prediction model of cumulative deformation of the foundation of the mined-out areas with different damage degrees under the long-term dynamic loading was proposed. The model parameters are closely related to the damage degree of foundation of the mined-out areas. The conclusions obtained in this study provide a theoretical basis for the prediction and control of the cumulative deformation of the foundation of the mined-out areas under the dynamic loading of high-speed railway.