考虑支护作用的巷道围岩塑性区边界方程及应用

Boundary equation of plastic zone in roadway surrounding rocks considering supporting effect and its application

结合Mohr-Coulomb强度准则,推导考虑支护力作用下的非等压圆形巷道围岩塑性区边界方程的近似解,通过理论分析和数值模拟,得出支护阻力对巷道围岩塑性区范围和形态的影响作用。研究表明:在现有支护条件下,支护阻力能够使浅部低应力巷道围岩塑性区范围有一定程度的减小,特别是对于双向主应力比值较大情况下浅部巷道围岩塑性区呈现的蝶形扩展,支护阻力能起到较好的抑制作用;而对于深部巷道,现有支护阻力对减小其塑性区半径的作用不大,难以阻止深部巷道的大变形,支护对于深部巷道的作用在于阻止巷道围岩的破裂。深部巷道围岩控制,应由"变形控制"向"结构稳定控制"理念转变,以改善巷道围岩应力环境和围岩力学性能为主要途径,以预留变形和控制非连续变形为主要方法,尽量保证巷道围岩结构稳定、完整,满足使用要求。

combined with Mohr-Coulomb strength criterion,the approximate solution to the equation for plastic zone boundary in surrounding rock of circular roadway with unequal pressure considering support force was derived.The influence of support resistance on the range and shape of surrounding rock plastic zone was obtained through theoretical analysis and numerical simulation.The results have shown that under existing support conditions,support resistance can reduce plastic zone range in surrounding rock of shallow roadway with low stress to a certain degree,especially for butterfly expansion of plastic zone in surrounding rock of shallow roadway with large bidirectional principal stress ratio,where support resistance can have better effect in restraining.As for deep roadway,existing support resistance has little effect on reducing radius of plastic zone,and it is difficult to prevent large deformation of deep roadway;the role of support for deep roadway is instead to prevent fracture of surrounding rocks.Conceptualizations about surrounding rock control in deep roadways should change from"deformation control"to"structural stability control"with improving stress environment and mechanical properties of surrounding rocks as main pathways and reserving deformation and controlling discontinuous deformation as main methods,so as to ensure stability and integrity of surrounding rock structure and meet the application requirements.