现场勘查发现,神府矿区浅埋煤层群间隔岩层厚度大多在15～45 m时,间隔岩层易存在单一关键层结构。文章通过现场实测得出了浅埋煤层群开采周期来压的基本特征:来压步距减小、强度增大、煤壁片帮严重,动载现象、台阶下沉现象和大、小周期来压现象明显。物理相似模拟实验揭示了间隔岩层关键层与上煤层已扰动关键层同步与非同步破断的大、小周期来压机理,发现了间隔岩层关键层与已扰动关键层共同形成的“梁-拱-壳”结构形态,给出了上煤层已扰动关键层结构形态的判别方法,得出了浅埋煤层群开采顶板周期破断可形成“台阶-台阶”、“砌体-台阶”、“砌体-砌体”的基本结构。综合建立了浅埋煤层群开采间隔岩层周期破断结构与力学模型,给出了支架受动静载荷作用的工作阻力计算方法,并得到了现场验证。

Field investigation shows that when the thickness of interval layers is always between 15 -45 m in many shallow seam mining areas,the single key stratum structure is easily to be found. Taking the shallow-buried coal seam group in Shenfu mining area as an example,the periodic weighting of coal seam group mining has some basic charac-teristics identified by field measurement:short roof weighting step,high strength,serious rib fall of coal wall,dynamic load,step sinking and large and small cycle pressure phenomenon. The physical analogue experiments reveal the move-ments and “beam-arch-shell” structure of key stratum behind the goaf and over the mining seam with the broken key stratum by up-seam mining,the differentiation method of the broken key stratum over goaf,and the three basic roof structures of shallow buried coal seam with periodic breaking including the upper and lower step rock beams,the upper masonry beam-the lower step rock beam and the upper masonry beam-the lower masonry beam. Based on the periodic fracture structure and mechanical model of interval rock formation in shallow coal seam mining,this paper provides the calculation method of working resistance of support under static and dynamic loads which has been successful used. The conclusions are helpful for the control of periodical roof pressure shallow coal seam mining.