岩溶隧道衬砌疏水型箱式隧底结构研究

Research on the New Hydrophobic Box-Type Lining Structure in Karst Area

近年来,黔桂、广昆、沪昆等铁路隧道运营期间发生了若干起边墙开裂、仰拱隆起、无砟道床变形等水害事件,直接影响着衬砌、轨道等结构的正常使用功能及耐久性能,严重的病害则直接威胁着铁路隧道特别是高速铁路隧道的正常运营安全。为有效降低复杂岩溶地区隧道工程的水害风险,通过调研目前铁路隧道主要水害类型,分析现行衬砌排水系统存在的问题,提出一种适用于岩溶隧道的新型衬砌结构,通过建立有限元模型,对衬砌结构受力进行对比分析。主要结论如下:(1)研究提出的“疏水型箱式隧底衬砌”,具有“隧底开挖施工方便、不良地质适宜性强、排泄路径直接、隧底泄水快、排水断面自由度高、泄水能力强”等特点,能充分满足复杂岩溶隧道受力及排水的需求;(2)同现行仰拱型衬砌结构相比,在不增加结构厚度及配筋的基础上,疏水型箱式隧底衬砌结构受力更为均衡。

In recent years,a number of water disasters,such as side wall cracking,inverted arch uplift and ballastless track bed deformation,have occurred during the operation of tunnels along the GuiyangLiuzhou,Guangtong-Kunming,and Shanghai-Kunming railways,which directly affected the normal service functions and duration of such structures as lining and tracks.Serious damages have resulted in severe threats to railway tunnels,especially high-speed railway tunnels.Thus,to effectively reduce the risk of water disaster to tunnel engineering in complicated Karst areas,recent problems in lining water drainage systems are analyzed based on researches on latest major types of water hazards,and a new type of lining structure applicable to karst tunnels is proposed.The stress of lining structure is compared and analyzed by setting up a finite element model.The main conclusions are as follows:(1)The proposed new hydrophobic box-type lining structure has several specialties like convenience to tunnel excavation works,high adaption to multiple unfavorable geological conditions,effectiveness of drainage routes,fast water draining at tunnel bottom,high degree of freedom of drainage section,which satisfy the draining and loading requirements of complicated Karst tunnels.(2)Compared with existed inverted arch lining structure,the hydrophobic box-type lining structure provides a more balanced load condition without increasing structure thickness and adding reinforcing bars.