地下采煤引起的破裂效应对斜坡稳定性影响分析

Influence of fracture on slope stability caused by underground coal mining

文中考虑了下伏基岩与上覆黄土物理力学性质差异性,通过物理模型试验对地下采煤引起上覆黄土坡体裂隙化规律进行了探讨,得出裂隙扩展具有明显序次和空间分异特征,可分为与坡面近垂直裂隙和与坡面近平行裂隙两组,前者的扩展对基岩顶面变形非常敏感,扩展速度快,范围广,密度大,具有拉张裂隙的特征,宽度较宽,裂隙两壁参差不齐;后者为前者派生裂隙,只在试验后期才逐渐出现,且集中在坡体内部,密度较小,具有剪切裂隙的显著特征,裂隙比较紧闭,局部呈羽列状。破裂效应对斜坡稳定性的影响分析表明,地下采煤导致的上覆斜坡坡度变化对斜坡稳定性的影响较小,裂隙密度、产状对斜坡应力状态的影响是地下采煤引发斜坡失稳的关键因素之一。

Considering the differences in the physical and mechanical properties of underlying bedrock and overlying loess,the fractures development laws in overlying loess slope caused by underground coal mining were discussed through physical model tests,and the effect of fractures on slope stability was analyzed.It is concluded that the expansion of fractures has obvious spatial differentiation characteristics and orderly appearance.The fractures can be divided into two kinds:approximately vertical and parallel to the slope surface.The formers are very sensitive to the deformation of the top surface of the bedrock.They expanded with fast speed,wide range,high density,and have the characteristics of tension fractures with wide width and uneven walls.The latter are often generated along with the expansion of the near-vertical fracture and the deformation of the slope.They only gradually appear in the later stage of the test.Their range is concentrated inside the slope and their density is small,and have the characteristics of shear fracture,which is plume-shaped and closed.The analysis of the influence of fractures on the slope stability shows that the fracture density and attitude are the key factors influencing the slope stress state,while the overlying slope change caused by underground coal mining has little effect on the slope stability.