富水区隧道二次衬砌混凝土施工冷缝致灾机理研究  

Mechanism Study of Disaster Caused by Cold Joint in Tunnel Secondary Lining Concrete in Water⁃rich Area

作　　者：董武 DONG Wu(Safety Supervision and Management Administration,CHINA RAILWAY,Beijing 100844,China)

机构地区：[1]中国国家铁路集团有限公司,安全监督管理局,北京100844

出　　处：《铁道建筑》2021年第9期48-51,共4页Railway Engineering

基　　金：中国国家铁路集团有限公司系统性重大项目(P2019G040)。

摘　　要：针对一富水区隧道冷缝附近二次衬砌混凝土大面积掉块脱落问题,采用数值模拟方法分析了掉块脱落区段二次衬砌结构的受力特征,研究了在局部高水压条件下冷缝的致灾机理。结果表明:冷缝与环向施工缝相交处为结构受力薄弱区,在局部集中荷载作用下二次衬砌存在向内脱出倾向;掉块区侧沟、纵向盲管等排水设施基本堵塞,地下水无法顺利排出并在二次衬砌背后聚集,在强降雨、高水头和围岩荷载的共同作用下,冷缝和施工缝附近的混凝土第一主应力和剪应力超出材料极限强度,进而导致掉块脱落。隧道衬砌背后的防排水系统由于其隐蔽性,出现问题极难恢复至原有状态,应在建设期将其做好做精。Aiming at the large-scale spalling problem of secondary lining concrete near the cold joint in water-rich area of a tunnel,numerical simulation was used to analyze the mechanical characteristics of the secondary lining in the spalling section,and the mechanism of disaster caused by cold joint under local high water pressure condition was studied.The results show that the intersections of the cold joint and the circumferential construction joint is the weak area of the structure,and the secondary lining tends to bulge inward under a local concentrated load.Drainage facilities,such as side ditches and longitudinal pipes in the spalling section are almost blocked,and groundwater could not be discharged smoothly but gathers behind the secondary lining.Under the combined action of heavy rainfall,high water head and surrounding rock load,the first principal stress and shear stress of the concrete near the cold joint and construction joint exceed its corresponding ultimate strength,which will lead to spall.The waterproof and drainage system behind the tunnel lining is extremely difficult to restore to its original state due to its concealment.Therefore,it should be done well during the construction period.

关 键 词：铁路隧道 冷缝致灾 数值模拟 隧道冷缝 排水系统堵塞 衬砌掉块 衬砌空洞 

分 类 号：U459.1[建筑科学—桥梁与隧道工程]