深井覆岩采动冒落及孔隙率分布特征研究  

Research on Mining Caving and Porosity Distribution Characteristics of Overlying Strata in Deep Wells

作　　者：聂琦苗 牛会永 刘轶康[1,2] 鲁义 李石林 NIE Qi-miao;NIU Hui-yong;LIU Yi-kang;LU Yi;LI Shi-lin(School of Resources and Environment and Safety of Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;Hunan Provincial Key Laboratory of Coal Safety Mining Technology,Hunan University of Science and Technology,Xiangtan 411201,China)

机构地区：[1]湖南科技大学资源环境与安全工程学院,湖南湘潭411201 [2]湖南科技大学煤炭安全开采技术湖南省重点实验室,湖南湘潭411201

出　　处：《煤炭技术》2021年第11期18-22,共5页Coal Technology

基　　金：国家自然科学基金资助项目(51874131,51474106,51274099);湖南省教育厅优秀青年项目(18B213)。

摘　　要：为准确研究深井采空区覆岩冒落特征及孔隙率分布规律,利用FLAC3D模拟软件建立了深部煤矿工作面的采空区物理模型,模拟了覆岩在采动过程中的破坏变形和冒落规律,确定“两带”的最大高度,定量分析覆岩应力、位移分布规律,建立了采空区孔隙率的三维分布模型,并将孔隙率函数模型导入FLUENT软件,模拟深井采空区的氧气浓度场和瓦斯运移规律,验证其孔隙率模型的适用性。研究表明:冒落带的范围距离煤层上方17 m,裂隙带的范围在煤层上方17~64 m。走向方向上,支撑压力峰值随着工作面的推进而不断增大,下沉量由工作面向采空区深处逐渐变大;在倾向方向上,以采空区中心为原点垂直应力呈对称分布,下沉量呈中间大,两边小分布;垂直方向上,支撑压力峰值距离煤层越远越小。采空区孔隙率呈“簸箕”状,在煤壁处较大,中部低。采空区氧气浓度和瓦斯运移的变化趋势与实际井下情况相符合,验证了孔隙率函数模型的适用性。In order to accurately study the fluctuation characteristics and porosity distribution law of the covered rock in the deep well mined space area,the physical model of the working surface of the deep coal mine was established with FLAC3D simulation software,simulate the damage deformation and fluctuation law,determine the maximum height of the"two belts",quantitatively analyze the covered rock stress and displacement distribution law,establish a three-dimensional distribution model of the porosity in the mined space area,import the porosity function model into FLUENT software,simulate the oxygen concentration field and gas transport law in the deep well mined space area,and verify the applicability of the porosity model.Research show that the landing zone is 17 m,crack zone above the coal seam 17 to 64 m.In the oriented direction,the support pressure peak increases with the advancement of the working surface,and the sinking volume gradually increases from the depth of the mining area;in the inclined direction,the vertical stress at the center of the mining area is symmetrically distributed,the sinking volume is large in the middle and small distribution on both sides;in the vertical direction,the farther the support pressure,the smaller the coal seam.The porosity in the mining area is"dustpan",large at the coal wall and low in the middle.The changing trend of oxygen concentration and gas shift in the mined-out area coincides with the actual downhole situation,verifying the applicability of the porosity function model.

关 键 词：覆岩冒落 采空区 孔隙率 下沉量 数值模拟 

分 类 号：TD31[矿业工程—矿井建设]