地下洞室围岩劈裂破坏判据及数值模拟研究

Splitting failure criterion and numerical simulation for underground surrounding rock masses

对地下洞室围岩劈裂破坏的形成机理和裂纹扩展演化模型进行探讨。根据断裂力学原理,考虑原裂纹对翼型裂纹的影响,推求压剪应力状态下翼型裂纹尖端的应力强度因子K Iwing演化方程。以金川三矿区为工程背景,根据实测的岩石力学相关参数和地质条件,数值模拟其围岩的劈裂破损区。当翼型裂纹应力强度因子K Iwing达到岩石的Ⅰ型断裂韧度KIC时,地下洞室围岩裂纹发生劈裂贯通的破坏判据,用FISH语言将劈裂破坏判据编程内嵌到FLAC3D中确定围岩的劈裂范围。研究结果表明:数值模拟结果可为地下工程的稳定性评价及支护设计提供参考。

Mechanism of splitting failure and crack growth model were discussed in underground caverns surrounding rock masses.According to fracture mechanics theory,the evolutive equation of wing crack stress intensity factor,K Iwing,was deduced in compressive shear stresses state,in which the effect of original crack on wing crack was taken into account.The splitting failure criterion of underground caverns surrounding rock masses was put forward when wing crack stress intensity factor（K Iwing） was up to the mode-Ⅰ fracture toughness of rock（KIC）.The criterion was programmed into FISH language and embedded into FALC3D.Taking Jinchuan Mine as an engineering case,the splitting failure range was simulated by rock mechanics parameters and geological condition.The results show that the estimated results can provide basis for stability evaluation and support design.