岩溶隧道不同排水量对衬砌结构内力影响的数值模拟研究

Numerical Simulation and Research on the Influence of Different Discharge Volume on Internal Force of Lining Structure in Karst Tunnel

在高水头作用下,排水不及时高压水积压在衬砌周围,极易造成运营中隧道发生开裂、漏水等灾害,为了解决富水岩溶隧道衬砌后水压问题以及减少运营时衬砌长期在水压作用下的病害问题,依托桐梓隧道展开双场作用下排水量的数值模拟研究。采用有限元数值软件建模设计6种排水工况和5种水头工况,揭示了不同水头和排水量对衬砌内力和外水压力的分布特征。经研究发现:在有效的排水作用下,衬砌拱顶并不会产生较大正弯矩,在排水量不变时增加水头高度,仰拱及拱腰出会出现较大负弯矩和正弯矩,在水头高度逐渐增高时,衬砌会遭到破坏,在高水头相较于低水头条件下导致数值模拟出现较大偏差;当水头不变时,排水量增加会使衬砌内力显著减小。研究结果可为类似富水岩溶隧道结构设计、施工以及运营期排水提供一定的借鉴。

Under the action of high water head,untimely drained water and accumulated high pressure water around the lining can cause cracking,water leakage and other disasters in the operation of the tunnel.In order to solve the problem of water pressure behind the lining of water-rich karst tunnel and reduce the long-term defects of the lining under the action of water pressure,the numerical simulation of drainage under the action of two fields is carried out based on Tongzi Tunnel.The finite element numerical software is used to establish model and design six drainage conditions and five water head conditions,and the distribution characteristics of internal force and external water pressure of lining with different water head and displacement are revealed.It is found that the lining vault does not produce large positive bending moment under the effective drainage,when the displacement is constant,the invert arch and the arch waist will have large negative bending moment and positive bending moment.When the head height increases gradually,the lining will be destroyed,which leads to a large deviation in numerical simulation under high head compared with low head conditions.When the water head is constant,the internal force of lining decreases significantly with the increase of displacement.The research results can provide some reference for design and construction of similar water-rich karst tunnel structure as well as drainage during operation period.