An experimental investigation of pressure variation during train passage in tunnel

Abstract

When a train travels through a tunnel at high speed, large pressure variations are generated in the tunnel. They impose loads on tunnel lining, equipment inside the tunnel, and the train. It is thus necessary to accurately estimate these pressure variations in order to specify the design loads for them. Model experiments are effective in investigating these pressure variations. In the model experiments, we have used axisymmetric train models, because the train model is launched by friction drive consisting of some pairs of vertically aligned wheels. However, the experiments using axisymmetric train models can not accurately simulate the pressure variations in the area close to the passing train. Therefore, we have developed a launcher which can shoot an actual shape train model at the maximum speed of 250km/h by rotating wheels, and performed model experiments using both the actual shape models and the axisymmetric models. The results show that the pressure variations in the area close to the train using actual shape train model and actual shape tunnel model agree well with those of field measurements, and the magnitude of the pressure variations is inversely proportional to a square of an observation distance. Furthermore, the results have been verified by an acoustic analysis.