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在西南地区城市交通工程建设过程中,轨道交通隧道经常需穿越高水压富水地层。由于不同的隧道防排水设计理念对富水岩溶隧道衬砌外水压力及对隧址区生态环境和工程造成的影响差别较大,甚至可能导致衬砌结构破坏等问题。在“主动堵水,限量排放”隧道防排水设计理念下,以重庆市某轨道交通线中梁山隧道富水岩溶段为工程背景,采用FLAC3D有限差分软件分析了衬砌背后排水系统畅通性对隧道衬砌塑性区分布的影响,研究结果表明:随着排水孔失效长度的增加,二次衬砌背后的最大孔隙水压力增大,衬砌结构安全系数减小;塑性破坏区主要发生在仰拱区域,且在开挖后短时间内形成超静水孔隙水压力,引起该区段仰拱底部压力增大,可能导致隧道发生底鼓。
In the process of urban traffic engineering construction in southwest China, rail transit tunnels often need to cross high water pressure water-rich formations. Due to different design concepts of tunnel drainage and drainage, the external water pressure of water-rich karst tunnel lining and the impact on the ecological environment and engineering in the tunnel area are quite different, and even the lining structure may be damaged. Under the concept of “waterproofing and limited discharge” of tunnel, this paper takes the water-rich karst section of Zhongliangshan Tunnel of a rail transit line in Chongqing as the engineering background, and uses FLAC3D finite difference software to analyze the smoothness of the drainage system behind the lining The results show that with the increase of the failure length of the drainage hole, the maximum pore water pressure behind the secondary lining increases and the safety factor of the lining structure decreases. The plastic failure zone mainly occurs in the inverted arch area, And the formation of ultra-hydrostatic pore pressure within a short time after excavation, causing the pressure rise at the bottom of the invert arch, may lead to the tunnel kick drum.