冲孔扰动区裂纹扩展模式及影响因素分析

Analysis of Crack Propagation Modes and Affecting Factors of Slotting Disturbed Area

通过建立不同的数值模型,模拟钻孔周围煤体在不同因素下裂纹扩展模式。结果表明:煤体侧压系数λ不同,裂纹扩展方向、应力分布也不相同且随λ增大,钻孔周围裂纹数线性增长;随着颗粒黏结法向与切向强度比值增大,剪切裂纹所占比例呈线性增加,煤体破坏形式由脆性转为塑性破坏;当摩擦系数f较小时,随f增大裂纹数迅速减少;达到一定值时,裂纹数缓慢降低;随后几乎不变。

Different model have been built to simulate the crack propagation modes under different affecting factors of hydraulic flushing area. The results show that:if lateral pressure coefficient λ is different, crack propagation direction and stress distribution are also different; with the increase of the ratio of normal strength of bond to shear strength, the proportion of shear cracks grow linearly, and thefailure mode of coal mass shift to ductile fashion from brittle fashion; the number of cracks increase sharply with friction coefficient f while f is small, but it change little with f when f reaches a critical value.