Research on the Influence of Shaft Area on Alleviating Tunnel Aerodynamic Effects Through Dynamic Model Test

Series of compression waves and expansion waves caused by EMUs entering tennels at high speed will give rise to a series of tunnel aerodynamic effects: excessive pressure change will not only has effect on the fatigue life of EMU bodies and subsidiary structures in tunnels but also endangers the riding comfort of passengers. In addition, tunnel micro-pressure waves can even cause noise which effect the surrounding environment. Installing ventilation shafts inside tunnels is helpful to alleviate tunnel aerodynamic effects and the area of ventilation shaft is an important parameter. Dynamic model test system in Central South University was used in this paper to test and analyze the compression waves and expansion waves caused by trains entering tunnels and micro-pressure waves formed at tunnel exit, and to compare the influence of shaft with different area on the pressure change inside tunnel, the pressure change on train surface and the micro-pressure wave amplitudes. Test results show that the pressure changes inside tunnel and on train surface can be reduced effectively when the shaft area is 10% of the tunnel area; The larger the shaft area is, the smaller the tunnel micro-pressure amplitude will be.