Stochastic Dynamic Response and Long-Term Settlement Performance of Superstructure-Underground Tunnel System Subjected to Subway Traffic Excitation

The vibration impact force of a long-term operation of subways affects the comfort of the residents living above the superstructure and long-term settlement deformation of tunnel foundation. A method for evaluating the dynamic response of superstructure-tunnel systems is important, especially because of the randomness of vibration impact force. The coupling effect of the randomness of train vibration excitation and nonlinearity of the geotechnical properties subjected to dynamic action leads to challenges in the evaluation of performance of superstructure-tunnel foundation soil systems under train vibration. In this study starting with the establishment of a stochastic dynamics model of subway vibration load excitation, the time histories of the subway vibration excitation samples, with rich probability characteristics in the same set system, were generated. According to the nonlinear dynamic finite element analysis, several nonlinear dynamic responses of the deterministic superstructure-tunnel foundation-soil system were obtained. Finally, the probabilistic performance evolution of superstructure-tunnel foundation-soil system was obtained by integrating the first-passage and probability density evolution theories, and the long-term deformation performance of tunnel foundation was evaluated using time-varying reliability. This study provides a reference for the dynamic evaluation of superstructure-tunnel foundation-soil systems.