摘要：研究目的:高速铁路隧道掉块频发可能引发严重的经济损失甚至人员伤亡。高速列车气动荷载在裂缝内的激化效应可能是导致裂缝拓展并最终形成掉块的重要原因。为防止高速铁路隧道掉块事故发生,加强隧道病害治理,应对衬砌裂缝气动荷载的激化效应展开针对性研究。本文基于Fluent软件采用有限体积法(FVM)和Pressure-Based求解器,考虑空气可压缩性,采用非稳态粘性k-ε湍流模型对裂缝空间内的气动压力进行模拟,利用该模型讨论环向、斜向、纵向裂缝气动荷载的时空特征,分析气动压力的频谱特征,并对比裂纹长度、宽度、深度及车速对裂缝面气动荷载的影响。研究结论:(1)压力波进入环向裂缝腔内具有瞬时性,而进入斜向与纵向裂缝腔内具有过程性;(2)环向裂缝压力峰值最大,为输入压力的5.32倍;斜向、纵向裂缝压力峰值分别仅为环向裂缝相应值的79.5%与64.9%;(3)环向裂缝气动压力PSD平均值是纵向裂缝和斜向裂缝相应值的4.04倍和1.54倍;(4)裂纹长度、宽度对裂缝面压力峰值的影响有限,裂纹深度与压力峰值满足线性函数关系,车速与压力峰值满足幂指数为2.3033的幂函数关系;(5)本研究成果可为高铁隧道的设计、隧道内裂缝的评估和修复提供参考。

摘要：The breakage and bending of ducts result in a difficulty to cope with ventilation issues in bidirectional excavation tunnels with a long inclined shaft using a single ventilation method based on *** discuss the hybrid ventilation system applied in bidirectional excavation tunnels with a long inclined shaft,this study has established a full-scale computational fluid dynamics model based on field tests,the Poly-Hexcore method,and the sliding mesh *** distribution of wind speed,temperature field,and CO in the tunnel are taken as indices to compare the ventilation efficiency of three ventilation systems(duct,duct-ventilation shaft,duct–ventilated shaft-axial fan).The results show that the hybrid ventilation scheme based on duct-ventilation shaft–axial fan performs the best among the three ventilation *** to the duct,the wind speed and cooling rate in the tunnel are enhanced by 7.5%–30.6%and 14.1%–17.7%,respectively,for the duct-vent shaft-axial fan condition,and the volume fractions of CO are reduced by 26.9%–73.9%.This contributes to the effective design of combined ventilation for bidirectional excavation tunnels with an inclined shaft,ultimately improving the air quality within the tunnel.