深部圆形巷道围岩能量的调整机制及平衡关系

Mechanism of energy adjustment and balance of rock masses near a deep circular tunnel

巷道开挖过程中,能量的调整与再平衡会深刻地影响围岩的力学行为,理解围岩中能量的变化规律有助于工程灾变的防控及支护方案的优化。从应力状态与变形协调角度出发,分析了深部圆形巷道围岩的变形破坏模式,研究了准静态、弹塑性卸载条件下围岩中能量的调整机制以及传递、转换规律。在数学上严格证明了围岩内部能量的平衡关系,并详细分析了各组份能量的物理意义。结果表明:能量由外部围岩输入并以径向压力做功的形式向内部围岩传递,此时输入的能量部分以弹性应变能形式储存于围岩内,部分通过塑性变形耗散,剩余部分则通过围岩压力做功的形式释放并用于抵抗支护压力(无支护时,此部分能量将转化为围岩动能),此过程严格满足能量守恒定律。

During the excavation of deep tunnels,the adjustment and balance of energy have a significant influence on the mechanical behavior of the surrounding rock masses.Understanding the energy changes in the surrounding rocks will facilitate the prevention of geotechnical disasters and the optimization of supporting schemes.The deformation and failure modes of the surrounding rock masses around a deep-level circular tunnel are analyzed by considering the stress conditions and deformation compatibility.The mechanism of energy adjustment and laws of energy transmission and transformation in the surrounding rock masses under quasi-static unloading condition are investigated.The energy balance in the surrounding rock masses is proved rigorously from the mathematical viewpoint,and the physical interpretations for each energy component are given.The results indicate that the input external energy from far region is transferred to near region in the form of work done by radial stress.The input external energy can be divided into three parts:the potential energy stored in the rock masses,the energy dissipated by plastic deformation and the work done by pressure of rock masses that will transfer into potential energy in supporting(or kinetic energy of the surrounding rock).The adjustment process of the whole energy accords with conservation of energy.