岳家岭隧道进口仰坡稳定性分析及治理措施研究

岳家岭隧道进口仰坡自然坡度45°~60°，高度约80 m，坡体为泥灰岩夹灰岩，整体形成顺向坡，洞口无作业场地，处理不当可能出现岩体崩塌，给边坡稳定和施工人员作业带来巨大安全隐患。为了排除隧道进口仰坡的安全隐患，根据野外调查和钻探、物探结果，对隧道进口山坡坡体进行稳定性分析，采用8级台阶式边坡清方、锚杆框架植草的永久防护措施和挂网喷混凝土的临时防护措施相结合进行仰坡防护，并设置施工便道圆管涵等排水系统，利用清方土形成施工作业平台，洞口边坡和作业平台稳定性满足要求。

Stability Analysis and Control Measures Study for the Upward Slope of Entrance of Yuejialing Tunnel

The natural grade of the upward slope of Yuejialing tunnel entrance is 45°~60°, with the height of about 80 m. In the slope, there is marl with limestone. The slope forms a whole dip slope and there are no working sites at tunnel entrance. If the rock mass is handled improperly, collapse may be induced, bringing huge security risks to slope stability and construction workers. In order to exclude the potential safety hazards of the slope of Yuejialing tunnel, according to the results of field investigation, drilling and geophysical prospecting, an analysis on the stability of the entrance slope of tunnel is carried out. The 8 steps slope clearing, anchor frame grass planting permanent protection measures and temporary protection measures combined with net shotcrete are used to protect the upward slope. The drainage systems are set up, such as a circular pipe culvert for pioneer road. The construction platform is formed by using cleared earthwork. The stability of the slope and construction platform at the entrance of the tunnel meets the requirements, which can provide reference for other similar projects.