Aerodynamics behavior and evolution mechanism of high-speed railway tunnel lining falling block

With the high-quality development of China’ s high-speed railway construction technology, the running speed of high-speed trains is constantly improving. Under the influence of high train speed and long service time, lining cracks and falling blocks in high-speed railway tunnels are increasingly prominent during the service period, seriously endangering the driving safety of high-speed trains. In order to investigate the influence of train wind and its flow field structure on the falling process of tunnel lining falling block under driving environment, a 3D air-solid coupling model of train-falling block-air was established to simulate the whole process of falling block moves from tunnel vault to ground under driving environment. The results are drawn as follows. (1) The falling process of lining falling blocks includes translation and rotation in three directions. The translational motion is mainly along the longitudinal motion of the train, the displacement of the longitudinal motion is approximately 4 times of the lateral displacement. The rotation is mainly along the horizontal axis. (2) The train wind and the lining falling block interact with each other. When the train wind acts on the falling block, the flow field around the falling block appears vortex and flows around, and then changes the motion posture and direction of the falling block. At the same time, the movement of the falling block further changes the structure of the flow field around it, which is repeated until it falls to the ground. (3) The longitudinal direction of the train is the main flow direction of the flow field structure. The train wind acts on the falling block, pushing its movement. As a result, the main movement direction of the lining falling block is along the longitudinal direction of the train. The lining falling block has different angle and different strength flow around the flow field structure with the change of time, so the rotation of the lining falling block is dominated by the horizontal axis. The research results have certain reference value for the prevention and control of the tunnel falling block disease and improvement of driving safety. © 2023, Central South University Press. All rights reserved.