复杂岩溶区溶洞储水与隧道衬砌相互作用  

The Interaction between Karst Cave Water Storage and Tunnel Lining in Complex Karst Area

作　　者：刘鸿[1] LIU Hong(Transportation Research Institute Co., Ltd., China Merchants Group, Chongqing 400067, China)

机构地区：[1]招商局重庆交通科研设计院有限公司,重庆400067

出　　处：《科学技术与工程》2020年第22期9140-9148,共9页Science Technology and Engineering

摘　　要：水压衬砌的稳定性研究仍是在富水区修建隧道工程所关注的重点问题。多数相关研究均是基于连续性“渗透”模型和Darcy定理的基础上开展的。基于前人研究成果,结合实际情况,发现工程中衬砌主要破坏原因区别于渗流破坏,进而确认该隧道支护结构破坏主要原因为隧道排水系统失效后短时间内衬砌背后溶洞储水作用下的变高水头水压致裂破坏,从而提出该力学模型为“荷载-结构”模型,而“荷载-结构”模型的关键问题在于确定衬砌所受岩溶水压力大小与分布形式。根据水文地质条件假定溶洞处于汇水期时其流量基本不变,结合工程地质条件推导了该工程区两类溶洞(“走向型”溶洞和“斜交型”溶洞)的体积计算公式,再换算确定不同时间范围内的储水体积,最后折算为衬砌所受应力边界条件。通过数值计算理论分析变水压下隧道的力学响应特点,通过与现场照片的对比可证明隧道衬砌破坏主要原因确为水压致裂,同时伴有一定的水体渗透、劈裂作用加剧失效,说明前述的假设研究具有一定合理性,针对研究结果对工程提出了防范措施要点。研究思路与理论研究成果可为类似工程提供借鉴与参考。The research on hydraulic lining stability remains a key topic in the tunneling projects in water-rich areas.The majority of related studies are based on the continuous“infiltration”model and Darcy's law.Based on the previous research results and the actual situation,the main reason for the failure of the tunnel's lining structure was different from seepage failure.The failure was confirmed as the elevated water head hydraulic fracturing damage under the water storage action of karst caves behind the linings in a short time after failure of tunnel drainage system.Therefore,a relevant mechanical model as a load-structure model was proposed.The crucial matter of the load-structure model was to determine the size and distribution pattern of karst water pressure borne by the linings.The flow of karst caves was assumed constant during the catchment period based on the hydrogeological conditions.Combined with the engineering geological conditions,the volume calculation formulas for two types of karst caves(strike caves and oblique caves)were derived,which were then converted to determine the water storage volumes in different time ranges and finally translated into the stress boundary conditions of linings.The mechanical response characteristics of the tunnel were analyzed at variable water pressures by numerical calculation.The main reason for the tunnel lining failure could be proved indeed hydraulic fracturing by field photos,while the accompanying certain infiltrating and splitting actions further aggravated such failure.It meant that the above hypothetic research was reasonable.Finally,preventive measures were put forward for the project based on the research findings.The ideas and theoretical results of this study can offer experience and reference for similar projects.

关 键 词：水压致裂破坏 “荷载-结构”模型 “走向型”溶洞 “斜交型”溶洞 ADINA 

分 类 号：TU43[建筑科学—岩土工程]