Deformation Characteristics and Dynamic Response of Prestressed Subgrade Structures

To investigate the reinforcement performance and dynamic response of a novel prestressed railway subgrade structure, a three-dimensional numerical model was established using FLAC3D and validated against scaled model test results. The effects of prestress level, reinforcement configuration, and train axle load on lateral deformation, subgrade-surface settlement, and dynamic response were systematically analyzed. Train-induced dynamic loading was simulated using an artificial excitation-force function. The results show that prestressing effectively increases the lateral confinement of the subgrade, suppresses outward slope deformation, and reduces surface settlement. Increasing the prestress level improves the overall settlement-control performance, while the reinforcement effect is influenced by the arrangement position of the lateral pressure plates and gradually decreases with increasing axle load. Under dynamic train loading, prestressing reduces both the dynamic-displacement amplitude of the subgrade surface and the acceleration peaks within the subgrade. These results demonstrate that the proposed prestressed reinforcement system can improve both the static deformation resistance and dynamic stability of railway subgrades and provide a reference for reinforcement design and parameter optimization.