深埋软岩隧道让压支护结构化实现方法

Structural Implementation Method of Yielding Support for Deep Tunnel in Weak Rock

为了使让压支护更科学地应用于深埋软岩隧道变形控制,改变常规初期支护以弯曲变形让压为主的力学模式,基于结构稳定理论和大变形力学理论,研究让压支护的结构化实现方法。研究结论包括:(1)围岩稳定以拱结构为基本力学模型进行分析,应采取整体性、系统性的控制措施;(2)初期支护应降低几何非线性的影响,实现变形大的让压需求,同时规避力学大变形效应;(3)初期支护在“柔刚–刚柔–强刚”的变刚度调平过程中,必须以承载能力和稳定性得到保证为前提;(4)围岩与初期支护形成叠合结构的关键是两者力学性能匹配程度和接触面抗剪切能力。

In order to make the yielding support scientifically applied in deformation control of deep tunnel in weak rock, the conventional support mode which mainly based on bending deformation yielding is changed, and the structural implementation approaches of yielding support is studied based on the theory of structural stability and large deformation mechanics. The conclusions can be listed as follows:(1) the stability of surrounding rock is analyzed with the arch structure as basic mechanical model, the integral and systematic control measures should be taken;(2) the influence of geometric nonlinearity should be reduced in the initial support, so as to realize the yielding demand of deforming largely, and avoid the occurrence of large deformation mechanical effect;(3) in the leveling process of variable stiffness " rigid-soft-rigid" of the initial support, it must be based on the premise that the bearing capacity and stability are guaranteed;(4) the key to the formation of composite structure between surrounding rock and primary support is the matching degree of mechanical properties and the shear resistance of contact surface.