山区高速列车通过大坡度长大隧道车外压力波动影响
The High-Speed Train in Mountain Area Is Affected by the Fluctuation of the Outside Pressure of the Vehicle through the Long Tunnel with Large Slope

随着我国西部山区高速铁路的快速发展，复杂地理环境下高速列车通过大坡度、高海拔特长隧道引发的车外压力波动问题日益凸显。此类压力波动不仅影响乘客舒适性，还可能危及车体结构安全与列车运行效率。既有研究多聚焦于平原地区标准隧道工况，对高海拔、大坡度与特长隧道耦合作用下的压力波动特性，尤其是双列车交会时的动态交互机制研究尚存不足。本文以时速400 km/h高速列车为研究对象，基于一维特征线法构建车外压力计算模型，系统分析海拔、坡度及隧道长度对两列车交会压力波动的影响规律，并揭示最不利隧道长度的确定机制。结果表明：随着坡度增大，车外压力波动幅值显著增强。短隧道中压力波动呈现剧烈瞬态特征；长隧道中压力波动趋于稳态，但负压值随隧道延长持续累积。通过线性拟合发现，车外压力峰峰值与坡度呈正相关，与海拔呈负相关，并建立多参数耦合公式，为工程设计提供量化依据。研究成果揭示了复杂线形隧道内压力波动的生成与演化机制，提出了最不利隧道长度的判定标准，可为山区高铁隧道断面选型、车体气密性优化及运营安全评估提供理论支撑。
With the rapid development of high-speed railway in western mountainous areas of China, the problem of external pressure fluctuation caused by high-speed train passing through large slope and high altitude long tunnel in complex geographical environment has become increasingly prominent. This kind of pressure fluctuation not only affects the passenger comfort, but also endangers the safety of the train structure and the efficiency of the train operation. Most of the existing studies focus on the standard tunnel working conditions in plain area, but there are still insufficient studies on the pressure fluctuation characteristics under the coupling effect of high altitude, large slope and long tunnel, especially on the dynamic interaction mechanism of double-train intersection. In this paper, a calculation model of the external pressure of a 400 km/h high-speed train is established based on one-dimensional characteristic line method, and the influence of altitude, slope and tunnel length on the pressure fluctuation of the two trains is systematically analyzed, and the mechanism of determining the most unfavorable tunnel length is revealed. The results show that the fluctuation amplitude of outside pressure increases significantly with the increase of slope. The pressure fluctuation in the short tunnel presents a sharp transient characteristic. In the long tunnel, the pressure fluctuation tends to steady state, but the negative pressure accumulates continuously with the extension of the tunnel. Through linear fitting, it is found that the peak value of external pressure is positively correlated with slope and negatively correlated with altitude. A multi-parameter coupling formula is established to provide quantitative basis for engineering design. The research results reveal the generation and evolution mechanism of pressure fluctuation in complex linear tunnels, and propose the criterion for determining the most unfavorable tunnel length, which can provide theoretical support for section