煤层采动地表变形特征及数值模拟研究

Numerical Simulation Research on Surface Deformation Characteristics and Numerical Simulation of Coal Seams

摘要: 为探究缓倾斜煤层开采地表变形规律及采深、倾角的影响机理，以邯郸峰峰矿区大社矿2^#、4^#煤层为研究对象，采用FLAC^3D构建三维模型，动态模拟双煤层分层开采全过程，分析不同开采阶段地表沉降及竖直位移变化规律，研究不同采深、倾角作用下的地表变形特征，并结合现场实测数据进行验证。结果表明：双煤层叠加开采地表沉降呈“椭圆形拱状分布”，最大沉降位于采空区正上方，向四周呈空间衰减趋势；随着煤层采深的增加，最大沉降值从1436 mm降至905 mm，降幅达37%，沉降影响范围减小42%；煤层倾角对沉降范围、程度、中心位置及形态影响显著，倾角每增加8˚，上山边界沉降量减少9%，下山边界增加11%。现场验证显示，FLAC^3D模型预测沉降值与实测值相对误差 ≤ 0.39%，精度可靠。研究成果为华北型缓倾斜煤层群的开采设计与生态保护提供量化依据。

Abstract: To investigate the law of surface deformation during gently inclined coal seam mining and the mechanism of coupling effects between mining depth and dip angle, this study focuses on the 2^# and 4^# coal seams of Dashe Mine in Fengfeng Mining Area, Handan. A three-dimensional model was established via FLAC^3D to dynamically simulate the full process of layered mining of the double coal seams. The evolution laws of surface subsidence and vertical displacement at different mining stages were analyzed, and the characteristics of surface deformation under the coupling effects of varying mining depths and dip angles were examined, with validation against field-measured data. The results indicate that surface subsidence induced by the superimposed mining of double coal seams exhibits an “elliptical arch-shaped distribution”, with the maximum subsidence occurring directly above the goaf and showing spatial attenuation toward the surroundings. As the mining depth of the coal seams increases, the maximum subsidence value decreases from 1436 mm to 905 mm, representing a 37% reduction, while the affected range of subsidence shrinks by 42%. The coal seam dip angle exerts a significant influence on the scope, magnitude, central position, and morphology of subsidence: for each 8˚ increase in dip angle, subsidence at the uphill boundary decreases by 9%, whereas subsidence at the downhill boundary increases by 11%. Field validation demonstrates that the relative error between the subsidence values predicted by the FLAC^3D model and the measured values is ≤ 0.39%, confirming high reliability. The research findings provide a quantitative reference for mining design and ecological protection of North China-type gently inclined coal seam groups.