大同矿区双系开采上覆采空区有害气体下泄条件及致灾特征

Discharge Conditions and Disaster Characteristics of Harmful Gas in Overlying Goaf of Dual System Mining in Datong Mining Area

多煤层开采中上覆采空区存在有CO、CH_(4)等有毒有害气体,该处有害气体能否发生下泄并致灾是目前多煤层开采威胁下伏煤层的安全生产需要解决的问题。论文针对大同矿区双系煤层开采上覆侏罗系煤层采空区有害气体下泄问题,应用关键层和材料力学等理论,对3-5^(#)煤层导气裂隙通道发育高度进行了理论分析,确定了石炭系煤层开采会致双系采空区间发生连通;结合多场耦合数值模拟方法,进行了侏罗系采空区有害气体下泄特征分析,确定了当双系间流场气压差大于400 Pa且裂缝通道大于0.4 m时,上覆侏罗系采空区有害气体会发生下泄现象,且可能致灾。研究成果可为相类似多煤层开采有害气体互扰防治提供理论依据。

CO,CH_(4)and other toxic and harmful gases exist in the overlying goaf of multi-coal seam mining.Whether the harmful gases can be released and cause disaster is a problem that needs to be solved in the safety production of the underlying coal seam threatened by multi-coal seam mining.Aiming at the problem of harmful gas leakage in the goaf of overlying Jurassic coal seam in Datong mining area,the development height of gas-conducting fissure channel in No.3-5 coal seam is analyzed theoretically by using the theory of key strata and material mechanics,and it is determined that the mining of Carboniferous coal seam will cause the connection between the goaf of double system.Combined with the multi-field coupling numerical simulation method,the analysis of the leakage characteristics of the harmful gas in the Jurassic goaf is carried out.It is determined that when the pressure difference between the two systems is greater than400 Pa and the fracture channel is greater than 0.4m,the harmful gas in the overlying Jurassic goaf will be discharged and may cause disaster.The research results can provide a theoretical basis for the prevention and control of harmful gas interference in similar multi-coal seam mining.