山区高海拔大坡度单线隧道内列车车外压力波动特性

External Pressure Fluctuations of a Train Inside a High-Altitude, Steep-Gradient, Single-Track Mountain Tunnel

摘要: 以川藏铁路拉林段为背景研究高海拔、大坡度与特长隧道群耦合作用下动车组车外压力波动特性，基于一维可压缩非定常流动模型，对时速160公里动车组单车通过川藏铁路拉林段典型隧道开展全参数数值模拟。结果表明，线路坡度是影响压力强度的关键因素，坡度增大导致车外压力峰峰值显著上升，而海拔升高对压力峰值具有削弱效应；短隧道内压力变化剧烈，以初始压缩波与膨胀波为主，长隧道则呈现压力梯度累积，中后段持续负压环境明显。隧道坡型与长度组合共同决定压力极值分布，“大坡度 + 长隧道”组合易引发最大压力峰峰值与尾部负压。研究结论可为川藏铁路高海拔隧道断面优化与列车气密性设计提供直接依据。

Abstract: Based on a one-dimensional compressible unsteady flow model, a comprehensive parametric numerical simulation was conducted for a single 160 km/h Electric Multiple Unit (EMU) train passing through typical tunnels in the Lhasa-Linzhi section of the Sichuan-Tibet Railway. The results indicate that the line gradient is a key factor affecting pressure intensity. An increase in gradient leads to a significant rise in the peak-to-peak value of the external pressure, whereas increased altitude has a mitigating effect on the pressure peak. Pressure changes are acute in short tunnels, dominated by initial compression and expansion waves, while long tunnels exhibit cumulative pressure gradients, with a pronounced sustained negative pressure environment in the middle and rear sections. The combination of tunnel gradient type and length jointly determines the distribution of pressure extremes. The “steep gradient + long tunnel” combination is prone to induce the maximum peak-to-peak pressure and tail negative pressure. The research conclusions provide direct guidance for the optimization of high-altitude tunnel cross-sections and the design of train air-tightness for the Sichuan-Tibet Railway.