基于车外压力波动400 km/h高速铁路最不利交会位置和最不利隧道长度
The Most Unfavorable Intersection Position and the Most Unfavorable Tunnel of the 400 km/h High-Speed Railway Based on External Pressure Fluctuation

随着高速铁路运行速度提升至400 km/h，列车在隧道内交会引发的车外压力波动对车体结构安全、隧道稳定性及乘客舒适性产生显著影响。本文基于一维流动模型特征线法，系统研究了两列车在不同隧道长度、交会位置及运行速度下的车外压力波动特性，旨在确定最不利交会位置与最不利隧道长度，为高速铁路设计与运营提供理论支撑。研究通过建立连续性方程、动量方程及能量方程，构建了一维可压缩非定常流动模型，并利用日本模型试验数据验证了计算方法的准确性。针对两列车等速交会过程，将其划分为驶入隧道、中央交会、驶向出口及驶出隧道四个阶段，分析了不同交会位置(中央交会、洞口交会、三分之一交会及四分之一交会)对车外压力峰峰值的影响。结果表明：中央交会时车外压力波动最为剧烈，最大正压值、最大负压值与压力峰峰值均达到峰值，例如在400 km/h速度下，856 m隧道内头车压力峰峰值达12.88 kPa，显著高于其他交会位置，故中央交会被确定为最不利交会位置。进一步探究隧道长度的影响发现，压力波动强度随隧道长度呈现非线性变化。在400 km/h速度下，571 m隧道内头车最大负压值达-10.32 kPa，压力峰峰值为13.66 kPa，较其他长度隧道分别提升2.28%~7.05%与3.45%~16.88%，表明571 m为最不利隧道长度。此外，速度对压力波动具有显著放大效应：450 km/h速度下，头车最大压力峰峰值达17.90 kPa，较300 km/h工况增长152.3%，且负压峰值出现时刻随速度增加提前。研究还揭示了车外压力动态演变规律：列车驶入隧道时压力线性上升，车尾完全进入后压力短暂降低，而对向列车进入引发的压缩波导致压力二次激增。两列车交会期间，压力波动幅值较单车工况更为剧烈，且尾车压力波动幅值低于头车与中间车。本文通过多参数耦合分析，明确了中央交会与571 m隧道为车外压力最不利工况，揭示了速度–隧道长度–交会位置的协同影响机制，可为400 km/h高速铁路隧道断面优化、车体强度设计及运营安全评估提供理论依据。
As the running speed of high-speed railway increases to 400 km/h, the external pressure fluctuation caused by trains crossing in the tunnel has a significant impact on the safety of vehicle structure, tunnel stability and passenger comfort. Based on the characteristic line method of one-dimensional flow model, the fluctuation characteristics of the external pressure of two trains under different tunnel lengths, intersection positions and running speeds are systematically studied in this paper, aiming to determine the most unfavorable intersection position and tunnel length, and provide theoretical support for the design and operation of high-speed railway. By establishing continuity equation, momentum equation and energy equation, a one-dimensional compressible unsteady flow model is constructed, and the accuracy of the calculation method is verified by the test data of the Japanese model. The equal-speed intersection process of two trains was divided into four stages: entering tunnel, central intersection, exit and exit tunnel. The influence of different intersection positions (central intersection, entrance intersection, third intersection and quarter intersection) on the peak value of external pressure was analyzed. The results show that the external pressure fluctuation is the most severe at the central intersection, and the maximum positive pressure, maximum negative pressure and pressure peak value all reach the peak value. For example, at the speed of 400 km/h, the peak