高速列车行驶速度对隧道壁面气动压力影响的数值模拟

壁面气动压力长期循环作用是高速铁路隧道衬砌掉块的重要诱因,为研究高速列车行驶速度对壁面气动压力基本特征的影响规律,采用三维数值仿真模拟对隧道典型位置(入口段、洞身段以及出口段)壁面气动压力进行研究。结果表明:列车车头经过使得监测横断面气动压力差异性增强,表现出显著的三维特征。隧道入口段气动压力三维特征主要受压缩空气所占体积大小以及与隧道入口之间距离的影响,气动压力三维特征随着进入隧道入口距离的增加而减弱,并逐渐向一维特征转变。列车车头驶入隧道入口后,车尾驶出隧道出口前,洞身段不同测点位置的气动压力正峰值主要受车头进入隧道入口诱发压缩波的影响,纵轴中断面测点气动压力负峰值与峰峰值大于洞口段。车尾驶出隧道出口后,出口段测点气动压力负峰值大于入口段,正峰值小于入口段。隧道出口段气动压力三维特征与入口段相似,但列车行驶速度以及测点与隧道出口之间距离对气动压力三维特征的影响机制更为复杂。

Numerical simulation of the influences of moving speed of high-speed train on aerodynamic pressure on tunnel wall

The long-term cyclic effect of aerodynamic pressure acting on tunnel wall is the important trigger of secondary lining detached from a high-speed railway tunnel wall. To investigate the influences of high-speed train"s speed on the basic characteristics of aerodynamic pressures, a three-dimensional numerical simulation was conducted to study the aerodynamic pressure at typical position of tunnel (near tunnel entrance, middle tunnel, near tunnel exit). The results show that the passing of train head makes the difference of aerodynamic pressure acting on monitoring cross section enhance, which showing obvious three-dimensional characteristics. The three-dimensional characteristics of aerodynamic pressure near tunnel entrance are mainly affected by the volume of compressed air and distance between monitoring cross section and tunnel entrance. The characteristics weaken with increasing distance, and gradually transform to one-dimensional. After train head entered the tunnel entrance, and before tail leaves exit, the positive peak value of aerodynamic pressure at different monitoring points of tunnel body are mainly affected by the compression wave induced by train head entering into tunnel entrance. The negative peak value and peak-to-peak value of aerodynamic pressure acting on the tunnel wall in the middle of tunnel"s longitudinal axis are greater than that near the tunnel entrance and exit. After train tail leaves the tunnel exit, the negative peak value near the tunnel entrance is greater than that near the tunnel exit, and the positive peak value is smaller than that. The three-dimensional characteristics of aerodynamic pressure near the tunnel exit is similar to that near the tunnel entrance. However, the effects of the train speed and distance on three-dimensional characteristics of aerodynamic pressure are more complicated.