特厚煤层仰采综放工作面过断层应力分布与围岩控制

Stress distribution in fault zone and surrounding rock control in upward fully-mechanized top coal caving face of extra thick coal seam

针对特厚煤层仰采综放工作面过断层时煤壁片帮及冒顶严重、围岩难以控制的问题,结合济宁二号煤矿10301工作面地质条件,采用理论分析的方法得出工作面过断层时要采取的合理措施,并通过数值模拟方法得出工作面过断层时的应力、塑性区演化规律。结果表明:仰采工作面过断层时超前15 m破底、下扎角为11°的方式推过F49断层最为合理;工作面推进至断层35 m时,超前支承应力峰值逐渐增大并向煤壁侧靠近,易造成煤壁片帮;与此同时,断层活化程度逐渐增强,基本顶超前垂直应力峰值增加,周期来压步距减小,顶板不易控制;当工作面推进至断层15 m时,工作面上方岩层塑性区开始逐渐导通断层,直至揭露断层时完全导通,研究结果提出了加强放煤控制、顶板管理措施,能确保10301工作面顺利通过断层。

In the view of passing the fault in upward fully-mechanized caving face of extra thick coal seam,the spalling and roof falling was difficult to be controlled.Based on geological conditions of No.10301 working face in Jining No.2 Coal Mine,reasonable path for passing fault was provided according to theoretical analysis and the stress and plastic evolution law were obtained using numerical simulation.The research results showed that it was more reasonable to go through Fault F49 in the distance of 15 m advanced cutting floor and the 11° advance broke angle.When the working face was advanced 35 m away from the fault,the peak of advanced abutment pressure became increasingly large and moved toward the coal wall side,which led to coal wall spalling.Meanwhile,the fault activation degree was gradually strengthened.The main roof＇s advanced vertical stress peak value increased and periodic weighting length decreased,which meant that the roof was hard to be controlled.When the working face was propelled 15 m away from the fault,upper strata plastic zone started to spread to the fault and until the fault was exposed,the fault was covered by plastic zone.After that,technical measurements were presented,such as strengthening coal caving control,roof management,to ensure the safety during the No.10301 working face passing the fault.