余吾矿回采面上覆岩层裂隙动态分布规律研究

Study on Dynamic Distribution Law of Overburden Fractures on Mining Face of Yuwu mine

为了研究工作面回采过程中上覆岩层裂隙的动态分布规律,基于UDEC软件,对回采过程中工作面上覆岩层的应力、位移和裂隙发育进行研究。结果表明随着煤层的回采,覆岩下沉量逐渐增大,煤层顶板处垂直位移变化最大,范围也最大,覆岩上部距煤层越远,其下沉量越小。在开切眼前方和工作面后方形成大量裂隙,而在采空区中部,裂隙分布较少。根据裂隙情况划分三带高度,其中冒落带高17 m,裂隙带高64 m,与经验公式推导相符合。计算孔隙率分布,在开切眼前方孔隙率达到0.25,工作面后方孔隙率达到0.35。结合公式,可得出采空区三维孔隙率变化图。

In order to study the dynamic distribution law of Overlying strata fissures during the mining process,the UDEC software is used to study the stress,displacement and fracture development of the overburden layer on the working face during the mining process.The results show that with the mining of coal seam,the subsidence of overburden gradually increases,the vertical displacement of the coal seam roof changes the most,and the range is also the largest.The farther the overlying rock is from the coal seam,the smaller the subsidence.A large number of cracks are formed in front of the open-off cut and behind the work surface,while in the middle of the goaf,the crack distribution is less.According to the fracture condition,the three zones are divided into three heights,among which the collapse zone is 17 m high and the fracture zone is 64 m high,which is consistent with the derivation of the empirical formula.The porosity distribution was calculated,and the square porosity in front of the cutting face reached 0.25,and the rear porosity in the working face reached 0.35 Combined with the formula,the three-dimensional orosity variation diagram of goaf can be obtained.