软弱地层桥隧相连隧道洞口滑塌综合处治技术研究

Research on Comprehensive Treatment Technology of Collapse for Tunnel Entrance Connected to Bridge in Weak Strata

为解决软弱地层桥隧相连隧道洞口滑塌的问题,以湖南省官新高速公路向家隧道为工程实例,分析了滑塌的原因和危害,结合规范和数值模拟、现场监测技术,采用工程类比法,通过对该隧道洞口滑塌处治技术进行综合研究,结果表明:①采用陡坡比削坡卸载+明洞结构、明暗交界处设置桩式套拱结构、抗滑桩顶部设置10 m空桩和较宽的锁口、人工挖孔滑裂面以上松散土体采用Ф42袖阀管注浆加固、仰坡之间设置较宽的反压缓冲平台、洞口设置抗滑桩和端墙式洞门等关键技术通过滑塌段,可以确保施工安全和后期桥梁运营安全;②建立了有限元数值模型,仿真分析了设计方案可行性,在施工过程中现场监测数据验证了方案的合理可行性;③设计施工案例,可供同类隧道参考。

In order to solve the problem of collapse at the tunnel entrance connected to bridges in weak strata,the Xiangjia Tunnel of Guanxin Expressway in Hunan Province was taken as an engineering example to analyze the causes and hazards of the collapse.The engineering analogy method,through comprehensive research on the treatment technology of the tunnel slump,the results show that:①Adopt the steep slope ratio cutting slope unloading+open hole structure,set the pile-type sleeve arch structure at the junction of light and dark,and set the 10 m empty pile on the top of the anti-sliding pile the loose soil above the slip surface and the wider lock opening and artificial digging shall be reinforced by grouting withФ42 sleeve valve pipe,a wider back pressure buffer platform shall be set up between the slopes,anti-sliding piles and end wall-type tunnel doors shall be set at the entrance of the tunnel.Through the slump section,and other key technologies,the construction safety and later bridge operation safety can be ensured;②A finite element numerical model is established to simulate and analyze the feasibility of the design scheme,and the on-site monitoring data during the construction process verifies that the scheme is reasonable and feasible;③This paper Design and construction cases can be used as a reference for similar tunnels.