Passenger ride comfort in subway due to new subway excavation below

Abstract

New tunnel excavation below existing tunnel deforms the rails inside the existing tunnel. The settlement-induced rail irregularity intensifies the wheel-rail interaction, which reduces passenger ride comfort of the existing tunnel. This research investigates the passenger ride comfort of the existing tunnel due to new tunnel excavation. A project of new twin tunnels excavation below existing triple tunnels is introduced. According to the field monitoring data, the settlement of each of the existing tunnels, although supported by different types of lining, can be fitted by the Gaussian function. Then numerical simulation is performed to study the deformation characteristics of the existing rails, which is difficult to monitor in the field. The simulation results show that the tunnel deformation can well represent the rail deformation. After that, train ride comfort is adopted to evaluate passenger comfort indirectly. The vehicle dynamic performance due to settlement-induced track irregularity is studied by a general multibody system simulation software. The results show that the vertical acceleration of the car body increases linearly with the increase of the settlement amplitude and decreases exponentially with the increase of the trough width i. When the trough width i is larger than 15 m, the vertical accelerations produced by new tunnel excavation are negligible compared to those produced by track irregularity. The settlement amplitude limits considering the passenger ride comfort in subway due to new subway excavation below are obtained.