基于流固耦合的下穿隧道及古运河安全性分析

Safety Analysis of Underpass Tunnel and Ancient Canal Based on Fluid-structure Coupling

针对处于富水软弱地层且下穿古运河的地铁隧道,采用流固耦合分析法,结合现场施工实测数据,分析各种工况下地下水渗流场、孔隙水压、隧道结构受力与变形、运河结构变形等问题,分析施工过程中威胁运河与隧道结构安全的主要因素包括孔隙水压增大、渗流带来结构压力、异步开挖造成二次扰动。隧道开挖造成隧道附近孔压急剧减小,甚至造成负压;后行洞施工增加先行洞1~2mm的变形;运河所处位置结构产生指向右洞的合位移;双洞变形过大存在超出控制指标的可能。提出在后行洞左边墙打设注浆锚杆、对运河结构增设变形监测点等措施,在实际施工中有效保护古运河及隧道结构。

This paper analyzes the groundwater seepage field,pore water pressure and tunnel structure stress and deformation,as well as deformation and deformation of the canal structure,under various working conditions by means of fluid-solid coupling analysis and the measured data of on-site construction for the subway tunnel in the weak water-rich stratum and below the ancient canal,the main factors that threaten the safety of the canal and tunnel structure during the construction process are explored.It is concluded that the hole pressure near the tunnel is drastically reduced by tunnel excavation,and even the negative pressure is caused.The construction of the subsequent hole increases the deformation of the first hole by 1~2mm,the position of the canal leads to the direction of the structure.The combined displacement of the right hole,the possibility that the double hole deformation is too large may exceed the control index.It is also proposed to set up grouting anchors on the left wall of the rear hole and add deformation monitoring points to the canal structure to effectively protect the ancient canal and tunnel structure.