近距离煤层上行开采覆岩裂隙演化与移动变形规律研究

Study on Fracture Evolution and Movement Deformation Law of Overlying Strata in Ascending Mining of Close Distance Coal Seam

以贵州某矿为工程背景,利用3DEC数值模拟软件建立了近距离煤层上行开采模型,研究上行开采过程中的覆岩裂隙演化及移动变形规律。结果表明:通过理论计算下煤层工作面回采覆岩冒落带和裂隙带最大高度,认为下煤层与上煤层的层间距大于下煤层工作面回采覆岩冒落带最大高度,小于覆岩裂隙带最大高度,采取底板加强措施后即可对上煤层进行开采;层间岩体强度越小,煤层开采覆岩裂隙越发育,离层现象明显,垂直位移越大,反之亦然;随着采深的增大,煤层开采覆岩裂隙越不发育,垂直位移越大。结果可为近距离煤层上行开采覆岩移动变形控制、实现煤矿绿色开采奠定基础。

Taking a mine in Guizhou as the engineering background,the 3DEC numerical simulation software was used to establish the ascending mining model of close distance coal seam,and the evolution and movement deformation law of overburden rock fracture in the process of ascending mining were studied.The results show that the maximum height of the caving zone and the fracture zone of the lower coal seam working face is calculated theoretically.It is considered that the interlayer spacing between the lower coal seam and the upper coal seam is greater than the maximum height of the caving zone of the lower coal seam working face,and less than the maximum height of the fracture zone of the overlying rock.The upper coal seam can be mined after the floor reinforcement measures are taken.The smaller the strength of the interlayer rock mass,the more developed the overlying rock fissures in the coal seam mining,the obvious separation phenomenon,the greater the vertical displacement,and vice versa.With the increase of mining depth,the less developed the overlying rock fissures in coal seam mining,the greater the vertical displacement.The re-sults can lay a foundation for the control of overlying strata movement and deformation and the realization of green mining in close distance coal seams.