Effects of train operational parameters on ground-borne vibrations induced by twin metro tunnels

Abstract

ABSTRACT Many underground railway lines consist of twin tunnels. The accurate prediction of ground-borne vibration levels is thus essential for this situation. This study investigates the train’s axle load and train's speed effect on the ground surface vibration response while two trains passed each other in the opposite direction in the twin subway tunnels. Firstly, a 3D finite element (FE) model of a twin circular tunnel in a homogeneous soil is developed and verified by the previous analytical studies. Then, sensitivity analyses are performed to assess the effect of train's speed and axle load on the ground surface response. The achieved results show that an increment of the train's speed in both tunnels causes increment PPV (Peak Particle Velocity) at the ground surface, but increasing the speed of one of the trains respect to the other one has a considerable influence on surface vibrations. The vibrations are increased about 2 dB and 3.5 dB by doubling the speed of both trains and one of the trains, respectively. Vibrations level at the ground surface is enhanced with increasing both trains axle load, but the ground surface vibrations are more sensitive to the difference between two trains axle load.