高速列车通过25‰单面坡隧道时，形成压力波和大气压两者耦合下的车内外压力变化特征，因此，有必要研究在隧道大气压持续变化下的高速列车通过大坡道隧道时的气动载荷和车内压力舒适性问题。采用实车试验的方法，获取动车组通过西成高铁西安北—汉中线路的列车车内外压力测试数据。研究结果表明： 1）列车下坡通过25‰特长隧道时车外压力波动受隧道压力波与大气压的共同作用，整体呈上升的变化趋势； 2）单面坡上坡和单面坡下坡隧道的长度由1 541.2 m增大至8 399.2 m时，列车车内外最大压力峰值越靠近隧道出口，单面坡隧道长度越长，列车车内外压力峰值越大； 3）随着大坡道隧道长度的增大，列车头车和尾车的整车气密效率在不断减小，列车车内Δp/1 s、Δp/3 s、Δp/10 s和Δp/60 s在不断增大，相应的车内压力舒适性环境更恶劣，当列车通过长大坡道隧道群时，车内压力舒适性环境和列车车体的气密性能更差； 4）与压力保护阀逻辑控制相比，压力保护阀全程关闭时列车车内压力和不同时间间隔下的最大压力变化量要更小，车内压力舒适性环境更优。
When a high-speed train passes through a tunnel with a 25‰ single-sided slope, the internal and
external pressure wave generated by the high speed of the train couples with
atmospheric pressure changes, resulting in distinctive internal and external
pressure variations. Therefore, it is necessary to study the aerodynamic loads
and in-train pressure comfort of high-speed trains passing through steep tunnels under various atmospheric
pressures. In this study, real-train test methods are
employed to obtain internal and external pressure data of a high-speed train passing through the Xi′an Bei
station-Hanzhong station of the Xi′an-Chengdu high-speed
railway. The results demonstrate the following: (1) When a single train
descends through a 25‰ extra-long
tunnel, the external pressure variation trend is consistent with the changes in
atmospheric pressure due to decreasing tunnel altitude. (2) As the tunnel
length increases from1 541.2 m to 8 399.2 m for both uphill and downhill single-sided
slopes, the maximum internal and external pressure peaks of the train occur
closer to the tunnel exit. Additionally, the maximum internal and external
pressure peaks of the train increase linearly with the tunnel length. (3) As
tunnel length increases, the airtightness of the train′s
head and tail continuously decreases, resulting in an increase in the Δp/1 s, Δp/3 s, Δp/10 s, and Δp/60 s,
which correspondingly leads to a deteriorating in-train
pressure comfort environment. When the train passes through long, steep tunnel
groups, both the train′s airtightness performance and
in-train comfort environment worsen. (4) Compared to
the logic control of the pressure protection valve, keeping the pressure
protection valve closed throughout the journey results in smaller internal
pressure variations and maximum pressure changes at different time intervals,
thereby improving the in-train comfort environment.
