极近距离煤层联合开采工作面合理错距研究

Research on reasonable malposition of combined mining in the ultra-close distance coal seams

基于山西灵石某矿极近距离煤层联合开采过程中存在的安全和技术问题,采用FLAC3D数值模拟研究方法,分析了上、下煤层联合开采工作面不同错距下上工作面覆岩应力传递规律,并结合现场工程实践,得出上下工作面联合开采的合理错距。结果表明:上下工作面错距为20m时上工作面煤壁前方垂直应力较大,应力集中系数为2.12;将上下工作面布置在26~35 m范围是保证安全开采条件下比较合理的错距,通过分析现场上工作面单体支柱压力数据,压力值普遍低于35 MPa,进一步论证了该错距范围的合理性。

According to the safety and technical problems of combined mining in close-distance coal seams of a mine in Lingshi county,Shanxi,the stress transfer law of overlying strata of upper working face under the condition of different malposition of upper and lower coal seam combined mining is analyzed,using FLAC3D numerical simulation research method.And in conjunction with the field engineering practice,the reasonable malposition of the upper and lower working surfaces is obtained.The results show that:When the upper and lower working face malposition is 20m,the vertical stress in front of the coal wall is larger,and the stress concentration coefficient is 2.12;The upper and lower working face malposition is arranged in the range of 26m^35m,which is the reasonable malposition to ensure safe mining.By analyzing the data of single pillar pressure in the upper working face,the pressure value is generally lower than 35MPa.Further,the rationality of the range of malposition is demonstrated.