Modeling of Vehicle-Track-Tunnel-Soil System Considering the Dynamic Interaction between Twin Tunnels in a Poroelastic Half-Space

The vibration prediction of a vehicle-track-tunnel-soil dynamic system is quite meaningful in engineering practice. However, the complexity involved in modeling the underground environment makes most previous studies ignore the impact of a neighboring tunnel. In this paper, a three-dimensional analytical model is presented to predict the vibrations of the vehicle-track-tunnel-soil system in a poroelastic half-space, with the dynamic interaction of two neighboring tunnels being considered. The vehicle was considered as a multibody system, and the slab and rail were simulated as Euler–Bernoulli beams. The twin tunnels were simplified as cylindrical thin shells, and the soil surrounding the tunnel was simulated as a saturated porous medium. Wave translation and transformation were applied to satisfy the boundary conditions of the interfaces between the tunnels and soil as well as the ground surface. By coupling the twin-tunnel model with the vehicle-track model, an analytical model for the vehicle-track-tunnel-soil system was obtained. The proposed model was validated by means of comparison with the existing solution. The numerical results demonstrate that the neighboring tunnel and water saturation have a significant effect on soil vibrations.