隆德煤矿浅埋上下煤层协调同采技术研究

Co-mining of shallow-buried upper and lower coal seams in Longde Coal Mine

为了确定隆德煤矿浅埋深1^-1煤与2^-2煤协调开采合理安全间距,采用CT探测技术及钻孔应力监测系统两种测试方法开展了上下煤层同采应力实测研究。研究得出:CT探测确定了2^-2煤层大采高工作面超前采动应力范围最大为59.5m,1^-1煤工作面顶板在采空区后方47.5m开始垮落,并影响下方2^-2煤工作面应力分布;钻孔应力计实测确定了2^-2煤层工作面超前应力影响距离最大50.7m,应力峰值超前于工作面6m,应力集中系数1.23,而2^-2煤层工作面不受间隔煤柱宽度20m的相邻工作面以及间隔顶板岩层厚度54m的上覆1^-1煤回采影响;采用了3种方法综合确定了隆德煤矿上下煤层协调同采合理滞后距离为138.4m。数值模拟研究表明,安全间距50m以内拉应力贯穿整个层间距,从而验证了隆德煤矿上下煤层协调开采安全间距138.4m的安全性。

In order to determine reasonable lag safety distance of shallow buried 1^-1 coal and 2^-2 coal seams in Longde Coal Mine,CT detection technology and borehole stress monitoring system are used to measure the simultaneous mining stress distribution of upper and lower coal seams.According to the CT detection,the leading mining stress range of 2^-2 coal seam for fully mechanized high-cutting face is 59.5 m,and roof of 1^-1 coal seam began to collapse at about 47.5 m behind the goaf,and affect the stress distribution of 2^-2 coal seam below.The borehole stress gauge has determined that the maximum distance affected by the leading stress on 2^-2 coal seam is 50.7 m,the stress peak is 6 m ahead of working face,and stress concentration coefficient is 1.23,but working face of 2^-2 coal seam are not affected by the adjacent working face with 20 m coal pillar and the overlying coal mining with an interval of 54 m roof layer thickness.Three calculation methods are used,according to which the reasonable lag distance of upper and lower coal seams co-mining is 138.4 m.The numerical simulation study shows that the tensile stress runs through the whole interval within 50 m,thus verifying the safety of the coordinated safe interval of 138.4 m between upper and lower coal seams in Longde Coal Mine.