浅埋偏压隧道锁脚锚管施工优化研究

Optimization Research of Foot Anchor in Shallow Buried Bias Tunnel

在浅埋偏压隧道软弱围岩段左右侧土压力不对称的情况下,采用MIDAS/Civil有限元分析软件对锁脚锚管与初支钢架连接结构的力学特性进行模拟分析。结合理论分析与现场试验结果,提出一种合理的锁脚锚管与初支钢架连接结构,并优化偏压侧锚管设置参数。研究表明,在钢架腹板处设置工字钢托梁,将锁脚锚管焊接在托梁上,能大幅度提高锁脚锚管的锁定效果,减小钢架变形;偏压侧设置4根锁脚锚管,并在锚管内套Φ22 mm螺纹钢,能有效提高锚管的抗剪能力,保障初支受力协调。

In the case of asymmetrical earth pressure of the soft rock section of the shallow buried bias tunnel,MIDAS/Civil software was used to analyze the mechanical characteristics of the connection structure between the lock foot anchor pipe and the steel frame.Combining theoretical analysis and field test results,a reasonable connection structure of the foot anchor and the steel frame is proposed,and the parameters of the bias side anchor pipe are optimized.Studies have shown that setting I-beam steel joists at the web of the steel frame and welding the lock foot anchor pipe to the joist can greatly improve the locking effect of the anchor tube and reduce the deformation of the steel frame.Setting four lock leg anchor pipes on the bias side,and sleevingΦ22 rebar inside the anchor pipe can effectively improve the shear resistance of the anchor pipe and ensure the coordination of the initial support force.