基于损伤理论的卸压钻孔围岩特性分析

    Analysis on Surrounding Rock Characteristics of Pressure Relief Borehole Based on Damage Theory

    • 摘要: 为了研究卸压钻孔施工后围岩应力及变形场分布规律,在基于岩石非线性脆性损伤本构模型及连续损伤理论的基础上,对非均匀应力场钻孔围岩损伤区范围及应力进行求解,得到钻孔围岩发生损伤时的初始地应力和极限地应力及损伤区半径的解析式。基于解析表达式,通过算例分析钻孔围岩侧压系数和围岩角度对初始损伤地应力的影响以及钻孔围岩脆性参数、侧压系数等对围岩损伤区半径及极限损伤地应力的影响。分析结果表明:非均匀应力场钻孔围岩发生初始损伤时的地应力同时与侧压系数和围岩角度相关;岩石的脆性参数对围岩损伤区半径及极限损伤地应力的影响与损伤度有关;而钻孔围岩发生一定程度损伤时的极限地应力受到围岩脆性参数、侧压系数的影响。

       

      Abstract: To study surrounding rock stress and strain field distribution after the construction of pressure relief hole, based on the nonlinear brittle damage constitutive model of rock and the continuous damage theory, the damage area and stress of surrounding rock in the borehole of non-uniform stress field are solved, and the analytical formulas of initial and limit geostress and radius of damage zone are obtained. Based on the analytical expression, the effects of the lateral pressure coefficient and the angle of the surrounding rock on the initial damage ground stress are analyzed through a numerical example. The effects of the parameters of brittleness and the lateral pressure coefficient on the radius of the damage zone and the stress of ultimate damage in the surrounding rock are analyzed. The results show that the ground stress of the borehole surrounding rock is related to the lateral pressure coefficient and the angle of surrounding rock. The influence of rock brittleness parameters on the radius of damage zone and the stress of limiting damage is related to the degree of damage. The ultimate geostress is affected by the brittleness parameter and lateral pressure coefficient of surrounding rock.

       

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