采动影响型地下煤火诱发地表裂隙率的时空分布模型

Space-time distribution model of ground fracture ratio caused by mining-induced underground coal fire

基于随机介质移动理论,构建了采动影响型地下煤火诱发地表裂隙率的时空统一分布模型,并实例分析了矩形火区引发地表线（张）裂隙率、面裂隙率以及剪裂隙率的分布及动态变化规律.地表线（张）裂隙率、面裂隙率和剪裂隙率的极大值分别分布在采（燃）空区边界内侧约20 m（约为煤层厚度的3~4倍）的位置、四周边界线的四个中点位置和四个边角端点所对应的地表区域.随着煤层燃烧,垂直于煤火发展方向上的线裂隙率以及空区边界处对应的地表面裂隙率均呈半正态曲线形式变化并最终稳定于最大值;而剪裂隙率、煤火发展方向上的线裂隙率及空区内部对应的地表面裂隙率均呈正态曲线形式变化.

A space-time unified distribution model of ground fracture ratio caused by mining-induced underground coal fire was proposed based on the theory of random medium movement. The distribution and dynamic change laws of ground line （tension） frac- ture ratio, areal fracture ratio and shear fracture ratio were revealed through the analysis of an example. The maximum values of these three categories of ground fracture ratio respectively distribute in the ground surface region corresponding to the 20-m inner side from the surrounding boundary, the 4 midpoints of the surrounding boundary, and the 4 marginal endpoints of goaf. With combustion of the coal seam, the line fracture ratio perpendicular to the fire development direction and the areal fracture ratio corresponding to the boundary of goal change according to the half normal curve and stable at the maximum, while the shear fracture ratio, line fracture rati- o along the fire development direction and the areal fracture ratio corresponding to the interior of goaf change according to the normal curve.