不同地应力条件下双孔爆破的数值模拟

Numerical simulation on two-hole blasting under different in-situ stress conditions

考虑岩石介质的非均匀性,把爆破过程视为爆炸应力波和爆生气体压力共同作用的结果,基于损伤力学理论建立了岩石爆破的力学模型,并对不同地应力条件下岩石双孔爆破裂纹演化规律进行了数值模拟,分析了不同侧压力系数和埋深对裂纹扩展规律的影响。数值模拟结果表明:①爆炸应力波导致裂纹的萌生,爆生气体压力则会使裂纹进一步扩展和贯通;②裂纹演化过程与地应力密切相关,裂纹扩展的主方向趋于最大地应力方向;③随着埋深增加和初始地应力增大,裂纹扩展半径和裂纹区面积减小,地应力对爆破致裂的抑制作用明显。

Based on damage mechanics theory,a mechanical model for rock blasting is established considering of the rock heterogeneity,in which rock blasting is considered as two consecutive stages,i.e.the dynamic stage caused by the stress wave and the static stage caused by explosion gas pressure.The cracks evolution of two-hole blasting under different in-situ stress conditions is numerically simulated.The numerical results indicate that: ① the initiation of cracks is induced by the blasting stress wave,while the explosion gas pressure can lead to the further propagation of cracks;② the cracks evolution is closely related to the in-situ stress conditions,and the cracks propagation direction coincides with the maximum compressive principal stress;③ the cracks radius and cracks area decrease with the increasing of depth and in-situ stress,which implies the suppression of in-situ stress on blasting fracturing.