厚煤层分层采动直覆砂岩运移规律研究

Study on the Migration Law of Direct Overlying Sandstone in Slice Mining of Thick Coal Seam

为分析厚煤层分层开采后直覆砂岩顶板岩层移动规律,以顾北矿A组煤南-1采区13121上工作面为工程背景,采用物理相似试验和理论分析相结合的方式对顾北矿厚煤层分层开采覆岩运动进行了研究。通过构建分层开采覆岩的结构力学模型,得出覆岩荷载计算公式。研究结果表明:直接顶垮落步距为85 m;工作面前方18~20 m处实体煤处于支承压力峰值,下分层应力峰值范围为19.07~23.35 MPa、上分层应力峰值范围为17.98~20.98 MPa;11.6 m厚细砂岩层及其下部岩层发生破坏,失去对其上覆岩层的承载能力,导致下分层的应力峰值大于上分层;上分层裂隙带高度为32 m,垮落带高度为17 m,下分层裂隙带高度为40 m,垮落带高度为23 m,下分层垮落范围比上分层发育。为顾北矿分层开采提供参考依据。

In order to analyze the migration law of direct overlying sandstone in slice mining of thick coal seam,the 13121^(up) working face of coal south-1 mining area in group A of Gubei mine was used as the engineering background.The overlying strata movement in the slice mining of the thick coal seam in the Gubei Mine was studied by combining physical similarity test and theoretical analysis.By constructing the structural mechanical model of slice mining of overlying strata,the calculation formula of overlying strata load was obtained.The results show that the collapse step distance of direct roof is 85 m.The solid coal at 18-20 m in front of the working face is at the peak of the supporting pressure.The stress peak range of the lower stratification is 19.07-23.35 MPa,and that of the upper stratification is 17.98-20.98 MPa.The fine sandstone strata with the thickness of 1l.6 m and its lower stratification were damaged,losing the bearing capacity of the overlying strata,resulting in a higher stress peak in the lower stratification than in the upper stratification.In the upper stratification,the height of fracture zone is 32 m,and the height of the collapse zone is 17 m.In the lower stratification,the height of the fracture zone is 40 m,and the height of the collapse zone is 23 m.And the collapse range of lower stratification develops larger than the upper stratification zone.The study can provide a certain guiding significance for the slice mining of Gubei Mine.