浅埋煤层群重复采动覆岩运移及裂隙演化规律研究  

Research on overburden movement and fracture evolution of repeated mining in shallow coal seams group

作　　者：张杰[1,2] 何义峰 罗南洪 郭建平 王斌[1] 吴建军 ZHANG Jie;HE Yifeng;LUO Nanhong;GUO Jianping;WANG Bin;WU Jianjun(School of Energy Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;Key Laboratory of Western Mine Exploitation and Disaster Prevention of Ministry of Education,Xi’an University of Science and Technology,Xi’an 710054,China;Shaanxi Yongxin Mining Co.,Ltd.,Yulin 719000,China)

机构地区：[1]西安科技大学能源学院,陕西西安710054 [2]西安科技大学教育部西部矿井开采及灾害防治重点实验室,陕西西安710054 [3]陕西涌鑫矿业有限责任公司,陕西榆林719000

出　　处：《煤矿安全》2022年第3期58-65,共8页Safety in Coal Mines

基　　金：国家自然科学基金资助项目(51774229,52004200);陕西省自然科学基础研究计划(陕煤联合基金)资助项目(2019JLM-41)。

摘　　要：为了准确掌握单一煤层和煤层群开采覆岩裂隙演化规律及分布形态特征,通过物理相似模拟实验、现场钻孔勘探、理论计算等方法分析煤层开采过程中覆岩运移破断特征及采动裂隙的分布形态。结果表明:在重复采动条件下,覆岩出现离层裂隙和纵向裂隙并伴随超前裂隙的产生,形成“采空区-工作面”和“采空区-采空区-工作面”结构时,覆岩裂隙经历产生、扩张、闭合、再产生、贯通、再闭合等6个动态循环变化阶段;煤层群在一次采动时形成“梯形”裂隙区,二次及多次采动下,覆岩受上覆载荷作用,裂隙区向工作面两侧煤柱扩展,上煤层受本煤层边界煤柱和下煤层开采形成的“悬臂岩梁”支撑影响,使工作面两侧裂隙明显高于工作面中部,覆岩形成“M”形裂隙分布形态;覆岩受采动影响产生周期性破断,以单岩层或多岩层同时产生变形、运移、破断垮落,由此可见,覆岩中存在控制上部岩层的硬岩层和其控制岩层以组合梁的形式同步运移、破断。根据覆岩破断特征建立了基于Winkler弹性地基煤层群重复采动覆岩破断特征的组合岩梁力学模型,由模型计算得到覆岩裂隙演化高度和相似模拟实验及现场所测高度相近,由此表明,该模型可作为浅埋煤层群重复采动覆岩裂隙演化高度计算的依据。In order to accurately grasp the evolution laws and distribution characteristics of the overburden cracks in the mining of a single coal seam and coal seam group,physical similar simulation experiments,on-site drilling exploration,theoretical calculations and other methods are used to analyze the characteristics of overburden migration and fracture and the characteristics of mining cracks during coal mining.The research results show that under repeated mining conditions,stratified cracks and longitudinal cracks appear in overlying rocks accompanied by advanced cracks.In forming a structure of“goaf-workface”and“goaf-goaf-workface”,the overburden fissures experienced six dynamic cyclical stages of generation,expansion,closure,re-generation,penetration,and re-closure.The coal seams group forms a“trapezoidal”fissure area during a mining.Under secondary and multiple mining operations,the overburden is affected by the overlying load.The influence of the“cantilever beam”formed by the coal pillars at the boundary of the coal seam and the mining of the lower coal seam makes the fissures on both sides of the working face significantly higher than the middle of the working face,and the overlying rock forms an“M”-shaped fissure distribution pattern.The overburden rock is periodically broken under the influence of mining,and deformation,migration and fracture collapse occur simultaneously in single or multi-rock strata.It can be seen that there is a hard rock layer that controls the upper rock layer and its control rock layer moves and breaks simultaneously in the form of composite beams.According to the fracture characteristics of the overburden rock,a composite rock beam mechanical model based on the failure characteristics of the repeated mining of the Winkler elastic foundation coal seam group is established.The evolution height of the overburden rock fissures calculated from the model is similar to the height measured in the similar simulation experiment and the site,which shows that this model can be

关 键 词：浅埋近距离煤层群 裂隙演化 相似模拟 组合岩梁 弹性地基 

分 类 号：P641[天文地球—地质矿产勘探]