地下采煤引起的黄土裂隙化物理模型试验研究

煤矿采空区的黄土边坡裂隙化严重,为研究地下采煤对黄土边坡裂隙化的影响,通过分级撤去缩尺模型底部支撑力来模拟开采过程,利用布里渊光纤应变测试仪监测各阶段中坡体的应变,结合其位移变化,分析黄土斜坡在地下采空条件下裂隙产生的位置、形态、斜坡体内部应力变化及黄土斜坡裂隙化规律。结果表明:地下采煤不仅导致黄土斜坡产生剪切裂缝还会产生拉张裂缝,产生裂缝的类型与采空塌陷的位置有关;地下采煤导致黄土斜坡产生的裂缝将切割斜坡,被切割的块体临空面较原始斜坡变陡,坡内应力状态发生变化,同时坡体完整性变差,天然强度降低;裂隙分布规律与采空塌陷边界基本一致;地下采煤引起的黄土裂隙化会改变坡体内应力重分布,重分布应力会产生次级裂缝,进一步破坏坡体。

Experimental Study on Physical Model of Loess Fissure Caused by Underground Coal Mining

The loess slope in goaf of coal mine is seriously cracked. In order to study the effect of underground coal mining on the fissure of loess slope, this paper simulates the mining process by unloading the bottom support force of the scale model step by step. The Brillouin fiber strain tester is used to monitor the strain value of the slope in each stage. Combining with the displacement change, the position, shape, stress change in the interior of the slope and the fracture development of loess slope are analyzed under the condition of underground goaf. The results show that underground mining not only causes shear cracks but also tension cracks on loess slope, and the type of cracks is related to the location of goaf collapse. The cracks on loess slope caused by underground mining will cut the slope, and the goaf face of the cut block will become steeper than the original slope, and the stress state in the slope will change. At the same time, the integrality of the slope is worse and the natural strength is lower; the distribution law of cracks is basically consistent with the boundary of goaf collapse; the Loess fissure caused by underground mining will lead to the redistribution of stress in the slope, and the redistribution stress will produce secondary cracks, which will further damage the slope.