Investigation of the Effect of Track on the Dynamic Stress in Saturated Soils Induced by the Moving Train Loads in a Shield Metro Tunnel

This study proposed an improved tunnel model for evaluating the dynamic stress in saturated soils subjected to moving train loads. The lining and grouting layer of the shield tunnel are modeled as a Flugge double cylindrical shell. The saturated soils are modeled as a poroelastic medium using the Biot's theory. The infinite rail and track slab are simplified as Euler-Bernoulli beams, and the track slab is coupled to the tunnel via one line of uniform supports. The rail, track slab, tunnel and soil medium are coupled by the compatibility of force and displacement at the contact surface. The developed tunnel model is validated against an existing tunnel model. Based on this model, the effect of railway track on the train-induced dynamic stress in the saturated soils is investigated by the proposed model. The model reveals that the track has significant influence on the magnitude and stress path of the dynamic stress in saturated soils.