为研究隧道单列车通过和2列车等速中央交会时隧道内中央处和洞口内压力波动机制和特征，隧道内各测点气动载荷最大正负压值和最大压力峰峰值沿隧道长度方向的分布规律，隧道长度对隧道气动载荷最值的影响，列车速度对气动载荷最值大小、位置和幅值频次的影响，以及基于隧道内最大压力峰峰值的最不利隧道长度的分布特征，采用一维非定常可压缩不等熵流动模型广义黎曼变量特征线法数值模拟方法和雨流计数法进行研究。结果表明： 1)单列车通过和2列车等速交会的隧道相同位置测点压力在一定时间内保持相同；列车驶出隧道后，压力波形周期重复，与压缩波/膨胀波在隧道内传播的周期相同。2)在3种速度和0.5~10 km隧道长度范围内，单列车通过时，隧道内最大正压值在距离隧道入口200~600
m的位置；速度增加，部分长度隧道的最大负压值和最大压力峰峰值位置由隧道中央近进口端内一侧变为隧道中央近出口端内一侧。3)当时速为400 km时，单列车通过基于不同隧道压力最值的最不利长度相同，为1.3 km； 2列车等速中央交会依次是1.4、0.94、1.2 km。4) 隧道单列车通过和2列车等速中央交会的最高幅值等级分别可达到4 800~5 200 Pa和10 000~10 400 Pa。
A one-dimensional unsteady compressible nonisentropic flow model,
incorporating a generalized Riemann variable characteristic line numerical
simulation method and the rain flow counting method, is employed to explore the
mechanisms and characteristics of pressure fluctuations at the center and
inside the entrance and exit of a tunnel during the passage of a single train
and the crossing of two trains at the same speed. The distribution patterns of
the maximum positive and negative pressures, the maximum pressure peak-to-peak values at various measurement points
inside the tunnel along its length, the influence of tunnel length on the
maximum tunnel aerodynamic load, the impact of train speed on the magnitude,
position, and frequency of amplitude, and the distribution characteristics of
the critical tunnel length based on the maximum pressure peak-to-peak value inside the tunnel are
obtained. The research results demonstrate the following: (1) The pressure at a
given location in the tunnel measurement points remains constant for a certain
time when a single train passes through and when two trains cross at a constant
speed. After the train exits the tunnel, the pressure waveform repeats
periodically, consistent with the propagation period of the compression or
expansion wave inside the tunnel. (2) When a single train passes through a
tunnel at three different speeds and tunnel lengths ranging from 0.5 to 10 km,
the maximum positive pressure value occurs 200－600 m
from the tunnel entrance. As speed increases, the position of the maximum
negative pressure value and the pressure peak-to-peak value for certain tunnel lengths shift from the near-inlet side toward the near-exit side of the
tunnel center. (3) At 400 km/h speed, the critical tunnel length based on
different maximum pressure loads is 1.3 km for a single train passage and 1.4,
0.94, and 1.2 km for the central meeting of two trains at a constant speed. (4)
The highest amplitude levels for single train passage and central meeting of
two trains at 400 km/h can reach 4 800 to 5 200 Pa and 10 000 to 10 400 Pa,
respectively.
