Numerical simulation of deformation of strata and stacked tunnels under traffic loads of subway

The traffic loads of subway have a significant impact on the strata and stacked tunnels. However, the existing studies have rarely focused on the deformation response of stacked tunnels and consider the influences of the location of the traffic loads. By selecting a stacked tunnel project in Tianjin, the excitation force function is used to determine the traffic loads, and numerical simulations are conducted to analyze the deformation of stacked tunnels under the traffic loads of subway. The results demonstrate that the position where the traffic loads of subway are applied significantly affects the displacement of strata and deformation of tunnels. Both S_max and i values are related to the location of data extraction. The critical influence range of lateral displacement caused by the traffic loads of subway is 1.5D from the center of the tunnel. Under the three conditions, the longitudinal deformations of the tunnels are overall downward. When the traffic loads of subway are applied only to the upper or the lower tunnel, the transverse deformation of the tunnel under the loads is large. When the loads are applied to two tunnels synchronously, both the two tunnels deform at the bottom.