隧洞岩爆机理与岩爆预测的断裂力学分析

Fracture mechanics analysis of rock burst mechanism and prediction

在应用断裂力学原理分析岩体裂隙扩展特点的基础上， 分析讨论了岩爆发生机理， 提出了隧道围岩应力强度因子等值线的概念， 认为隧洞岩爆将沿该应力强度因子等值线 ＫⅡθ＝ ＫⅡＣ圈定的范围崩落， 岩体裂隙失稳扩展导致隧洞岩爆的必要条件为同时满足裂纹开裂判据 ＫⅡ＝ ＫⅡＣ及裂纹失稳扩展判据ｋ ＋ ｆ′（δ） ＜ ０ ， 并指出同时满足这两个条件的岩体裂隙有临界开裂和临界止裂两个长度。

Based on the analysis for crack propagation in rockmass, the rock burst mechanism was analysed and the concept of stress intensity isogram for cavern's surrounding rockmass was proposed. The rock burst limits will be enclosed by this stress intensity isogram. The essential conditions for rock burst which caused by unstable crack propagation was simultaneously satisfied crack propagation criterion K Ⅱ θ = K ⅡC and unstable crack propagation criterion k+f′(δ) <0. The cracks which simultaneously satisfied these criteria exist critical initial fracture length and critical stop fracture length.