基于连续损伤理论的巷道围岩弹脆性损伤分析

考虑岩石的脆性损伤特性,引入非线性的岩石脆性损伤本构模型,将损伤演化方程从一维推广到三维,建立岩石损伤变量与脆性参数的关系。将圆形巷道围岩划分为损伤残余区、渐进损伤区和弹性区,采用弹脆性连续损伤理论,对巷道围岩损伤范围及应力进行求解。当巷道周边围岩只出现渐进损伤区时,推导出巷道围岩发生不同程度损伤的极限地应力及损伤半径;当巷道出现损伤残余区时,考虑围岩破坏后仍然具有残余承载能力的特点,推导出巷道围岩损伤区半径及围岩应力的表达式。通过算例分析了岩石损伤程度和脆性强弱对巷道围岩损伤半径及围岩应力场分布的影响,研究结果表明:岩石的脆性对损伤半径的影响跟损伤程度有关,岩石脆性越强,围岩切向应力的峰值越大;岩石损伤程度越大、损伤半径越大,切向应力峰值离巷道壁面越远。

Elasto-Brittle Damage Analysis of Roadway Surrounding Rock Based on Continuous Damage Theory

Considering the brittle damage properties of rock, the relationship of rock damage variable and brittle parameters was established by introducing the nonlinear brittle damage constitutive model of rock and inferring the damage evolution equation from one-dimensional to three-dimensional. The circular roadway surrounding rock was divided into damage residual zone, gradual damage zone and elastic zone, using elasto-brittle continuous damage theory, the analytic solutions of damage range and surrounding rock stress were deduced. When only the gradual damage zone appears in roadway surrounding rock, the limit in-situ stress and damage radius of different damage degree were deduced; when the gradual damage zone appears in roadway surrounding rock, considering the characteristics of damaged rock still has residual bearing capacity, the damage radius and stress distribution of roadway surrounding rock were deduced. Examples were given to show the effect of rock damage degree and brittleness on damage radius and stress distribution of roadway surrounding rock. The results show that the effect of rock brittleness on damage radius is associated with the damage degree of rock. The stronger the rock brittleness, the bigger the peak of tangential stress of surrounding rock will be. When the damage degree of rock is bigger, the damage radius will be bigger, then, the peak of tangential stress will be farther from the roadway wall.