煤层群重复开采采空区覆岩裂隙演化规律研究  

Study on Evolution Law of Overburden Rock Fissure in Repeated Mining Goaf of Coal Seam Group

作　　者：郭瑞睿[1] GUO Ruirui(Changzhi Vocational and Technical College,Changzhi 046000,China)

机构地区：[1]长治职业技术学院,山西长治046000

出　　处：《煤炭技术》2023年第9期81-85,共5页Coal Technology

摘　　要：明确重复开采下采空区覆岩裂隙演化规律是摸清卸压瓦斯运移规律的基础,借助UDEC数值模拟软件分析其重复采动下采空区覆岩裂隙演化特征,采用分形维数表征裂隙发育规律。结果表明:上行煤层推进150 m时裂隙带的最大发育高度为37 m,最终采空区覆岩裂隙在采空区两端较为集中,采空区覆岩裂隙发育历程大致可以分为裂隙产生、扩展,覆岩被压实裂隙减少3个阶段;重复采动下行回采煤层推进时覆岩垮落与工作面来压会提前发生,下行煤层推进至150 m时,垮落带高度为8.5 m,裂隙带发育高度为55.5 m,但受重复采动的影响,下行回采煤层裂隙提前发育,裂隙数量也会更大,工作面来压也更加剧烈;采用分形维数表征裂隙参数变化均印证了煤层不同回采阶段覆岩裂隙发展历程,验证了方法的可行性,为明确煤层群覆岩裂隙演化规律提供理论依据。Making clear the evolution law of overlying rock cracks in goaf under repeated mining is the basis for finding out the law of pressure relief gas migration.UDEC numerical simulation software was used to analyze the evolution characteristics of overlying rock cracks in mined-out area under repeated mining,and the fractal dimension was used to characterize the development law of cracks.The results showed that:when the upper coal seam is advanced 150 m,the maximum development height of the fracture zone is 37 m.Finally,the overlying rock fractures in the goaf are concentrated at both ends of the goaf.The development process of overlying rock fractures in the goaf can be roughly divided into three stages:fracture generation and expansion,and the reduction of overlying rock fractures by compaction.The overlying rock caving and the working face pressure will occur in advance when the downward backmining coal seam is advanced under repeated mining.When the downward coal seam is advanced to 150 m,the height of the caving zone is 8.5 m and the development height of the fracture zone is 55.5 m.However,due to the influence of repeated mining,the cracks in the downward backmining coal seam develop in advance,the number of fractures will be larger,and the working face pressure will be more intense.Using fractal dimension to characterize the change of fracture parameters confirms the development process of overburden fractures in different mining stages of coal seam,verifies the feasibility of the method,and provides a theoretical basis for defining the evolution law of overburden fractures in coal seam group.

关 键 词：重复采动 覆岩裂隙 数值分析 分形维数 

分 类 号：TD325[矿业工程—矿井建设]