Numerical Analysis of the Dynamic Response of a High-Speed Railway Foundation across a Ground Fissure Zone—A Case Study of the Datong–Xi’an High-Speed Railway Crossing a Ground Fissure in the Taiyuan Basin, China

The interaction between train vibration load and ground fissure disasters affects the safe operation of trains. However, the interaction between the high-speed railway foundation and the train vibration in the cross-ground fissure zone is not clear. To reveal the dynamic behavior characteristics of train vibration load crossing the ground fissure zone, the Da’xi high-speed railway passing through the ground fissure zone in the Taiyuan Basin is taken as the research object; the dynamic response of the high-speed railway foundation crossing the ground fissure zone at different angles was analyzed through dynamic finite element numerical simulation and orthogonal tests. The results show that when the high-speed railway crosses the ground fissure, the dynamic response fluctuates greatly at the ground fissure, which is manifested in the displacement and acceleration increase in the hanging wall and decrease in the footwall. The composite foundation reduces the fluctuation range and influences the scope of displacement, acceleration, and stress in the foundation of the ground fissure zone. The smaller the intersection angle between the high-speed railway and the ground fissure, the larger the influence range of displacement and stress, and the stability of acceleration at the hanging wall and footwall is poor. It is suggested that the high-speed railway pass through the ground fissure at a large angle. Additionally, the displacement fluctuation of the hanging wall and footwall can be controlled by increasing the pile length in the active area of the ground fissure.