大倾角煤层变角度综放工作面受倾角变化的影响,覆岩运移、矿压显现规律更为复杂。针对枣泉煤矿大倾角煤层120210变角度工作面综放开采条件,采用物理相似模拟实验和现场监测方法,对比研究了大倾角煤层变角度工作面和单一角度工作面综放开采覆岩运移规律。研究表明:120210工作面受不同倾角的影响,覆岩运移规律较单一角度工作面差异大,上部区域倾角26°,覆岩运移特征表现出倾斜煤层开采的特征,基本顶以“悬臂梁”结构形式发生破断运动,顶板平均压力23.7 MPa,分布均匀;下部区域倾角44°,覆岩运移特征表现为大倾角煤层开采特征,顶板垮落的矸石沿倾斜滑移充填采空区,顶板平均压力29.5 MPa,分布不均、变化范围大;中部区域过渡段覆岩运移既有倾斜煤层又有大倾角煤层开采特征,顶板平均压力27.15 MPa,分布较均匀,是两者转换的关键区域。根据工作面不同倾角区域覆岩运移、矿压显现特征提出大倾角煤层变角度综放工作面开采围岩控制原则,并依据此原则提出工作面分区域顶煤放出量控制方法。
Affected by variable angel, deformation, damage and movement of overlying strata in fully mechanized caving working face are more complicated than that in steeply dipping seam, which is ex-emplified by working face 120210 in Zaoquan coal mine. Based on its mining condition, a comparative study on movement of overlying strata respectively in steeply dipping working-face with variable angel and that with single angle is conducted through both similar simulation and field monitoring methods. The research has shown that 1) The movement law of overlying strata under different inclination angle in working face 120210 is crucially different from working face with single angle; 2) The overlying strata in the upper region with 26°angle has similar migration characteristics with inclined coal seam, the main roof in which region breaks and moves by cantilever beam structure with uniformly distributed roof pressure that values 23.7 MPa on average; 3) With an angle of 44°, the overlying strata in the lower region has similar migration characteristics with steeply dipping coal seam, and the caved rock slipped along dip direction and filled the gob; 4) The average roof pressure is 29.5 MPa, but it dis-tributes non-evenly and varies in a large scope; and 5) As a critical transition section between the upper region and the lower region, the middle region posses overlying strata movement law of both inclined seam and steeply dipping seam. The average roof pressure in this region is 27.15 MPa and distributes evenly. The surrounding rock control principle is put forward according to the overlying strata move-ment property and ground pressure apparent feature in different regions. And a sub-regional method is proposed to control top-coal caving quantity according to this principle.