采动覆岩裂隙分布及其空隙率特征

利用弹性薄板理论和关键层理论，对采空区上覆岩层的下沉进行定量描述，研究采动影响下覆岩裂隙的分布特征，得到了基于相对下沉量的覆岩规则移动带空隙率的近似公式。研究表明，覆岩裂隙场内，裂隙数量分布以两边为多，中部较少，在关键层下部的岩层往往产生较大的离层空间；随着岩层深度减小，空隙率逐渐变小，覆岩底部，空隙率曲线沿走向呈现马鞍状，在关键层或者硬岩起作用的区域形态发生改变，曲线形态逐渐变成拱状。其结论可应用于岩体渗流研究及瓦斯综合治理。

Study of distribution of overlying strata fissures and its porosity characteristics

Based on elastic thin plate theory and key strata theory, the stratum subsidence was described quantitatively. The characterization of fissures distribution in overlying strata under the influence of mining is studied. Then, an approximate formula of porosity in the regular movement zone of overlying strata along strikes is achieved. The results show that the amount of the fissures on both sides of fissure field is more than that in central area, while the bigger separation appears below the key strata. The porosity is lessening along with the decreasing of depth. Generally, the curve of porosity of bottom area in mining overburden takes on a saddle shape; and the change is located around the key strata or hard rocks. The porosity curve of top area along the strikes is symmetric arched. The conclusions can be applied to the research of rock mass seepage and the comprehensive gas control.