基于特征线法的车隧压缩波演化数值分析

为研究压缩波沿隧道传播演化的影响规律，采用考虑压缩波惯性效应和壁面摩擦效应的一维特征线法，建立了压缩波沿隧道传播演化的数值模型，通过一维平面波方程与实车测试两种方法共同验证了该模型的准确性。针对波前形状、车身波等、压力幅值关键因素，研究了初始压缩波沿隧道传播时，最大压力梯度的变化规律。在此基础上，进一步探讨分析了摩擦与气室阵列共同作用对压缩波波前演化的影响以及壁面摩擦的作用机理。结果表明：初始压缩波波形相同时，压缩波最大压力梯度随波前幅值的增大而增大；不同波形的初始压缩波沿隧道的演化规律不完全相同，但列车车身进入隧道所产生的车身波并不会影响压缩波波前的最大压力梯度；考虑壁面摩擦后，气室阵列对压缩波最大压力梯度的缓解效果有了进一步提高，壁面摩擦越大，缓解效果越显著。

Numerical Analysis of Tunnel Wavefront Evolution Based on the Method of Characteristics

In order to study the influence law of the compression wave propagation evolution along the tunnel, a numerical model of the compression wave propagation evolution along the tunnel was established based on the one-dimensional Method of Characteristics, which considered the inertial effect of the compression wave and the friction effect of the wall surface. The accuracy of the numerical model was verified by the one-dimensional plane wave equation and measured results. According to the key factors such as wavefront shapes, train body waves and pressure amplitude, the maximum pressure gradient of the initial compression wave propagating along the tunnel was studied. On this basis, the effect of friction and air chamber array on the compression wavefront evolution and the mechanism of wall friction were further discussed. The results show that the maximum pressure gradient increases with the increase of pressure amplitude when the initial compression wavefront shape is the same. The evolution of the initial compression wave along the tunnel of different wavefronts is not exactly the same, and the body wave generated by the train body entering the tunnel does not affect the maximum pressure gradient of the compression wavefront. After considering the wall friction, the mitigation effect of the air chamber array on the maximum pressure gradient of the compression wave is further improved, and the greater the wall friction, the more significant the mitigation effect.