400 km/h高铁隧道出入口缓解微气压波综合效果分析

Comprehensive Impact Analysis of Micropressure Wave Mitigation at Entrance and Exit of a 400 km/h High-Speed Railway Tunnel

为准确预测高速铁路隧道出口微气压波幅值,以三维、非定常、可压缩流动理论为基础,利用Fluent软件模拟时速400 km的列车驶入100 m2端墙式双线隧道时,分析列车在不同入口侧部开口缓冲结构、出口侧部开口缓冲结构及出口仰坡斜率下对出口微气压波的影响效应,并结合出入口缓冲结构综合分析微气压波联合缓解效果。结果表明:1)对出口微气压波峰值、出口缓冲结构、仰坡斜率进行相关性分析,结合辐射立体角公式线性拟合立体角变化趋势,得出立体角随缓冲结构开口率、洞门仰坡斜率的增大均呈现由急到缓的2段式上升曲线;2)数值分析得到在不同入口缓冲结构开口率下初始压缩波压力梯度变化规律和出口微气压波缓解效率规律,再结合隧道出口缓冲结构、仰坡斜率提出微气压波联合缓解效率预测公式,预测分析微气压波联合缓解效果在不同影响因素下的变化趋势;3)针对预测结果结合数值模拟验证工况进行误差分析,表明可以将出口立体角分析结果与入口缓冲结构缓解规律相结合。

To accurately predict the amplitude of the micropressure wave at the exit of a high-speed railway tunnel,Fluent software is used to simulate a scenario in which a train with an average speed of 400 km/h enters a double-track tunnel with an endwall area of 100 m2.The impacts of buffer structures at the side openings of the tunnel entrance and exit,as well as the slope gradient at the tunnel exit on the micropressure wave are analyzed.Furthermore,the combined mitigation effect of the micropressure wave is examined in conjunction with the entrance and exit buffer structures.The results indicate the following:(1)The correlation between the peak value of the exit micropressure wave,buffer structure,and slope gradient of tunnel exit as well as the variation trend of the solid angle linearly fitted by radiation solid angle formula demonstrates that the solid angle exhibits a two-stage ascending curve transitioning from sharp to gradual with increasing opening ratio of the buffer structure and slope gradient.(2)The numerical analysis reveals the variation law of the initial compression wave pressure gradient and the mitigation efficiency law of the exit micropressure wave under different opening ratios of the entrance buffer structure.A prediction formula for the combined mitigation efficiency of the micropressure wave is proposed,based on the buffer structure and the slope gradient of tunnel exit,to predict the variation trend under different combinations of multiple working conditions.(3)Following the error analysis between the prediction results and numerical simulation verification,the exit solid angle can be integrated with the mitigation law of the entrance buffer structure.