大倾角综放工作面矿压显现规律研究

Study on strata pressure behavior law of fully mechanized caving face with large dip angle

大倾角煤层综放工作面的覆岩破断特征与矿压显现规律受倾角大、“三软”和其他地质条件等因素影响,易出现支架钻底、煤壁失稳片帮、架间漏顶冒顶和支架咬架、倒架等问题,严重影响工作面的安全生产。本文以汾源煤业大倾角煤层5-101综放工作面为研究对象,采用物理相似模拟实验和现场监测的方法,分析了大倾角煤层综放工作面覆岩运移破断特征、顶板垮落步距及矿压显现规律。研究结果表明:大倾角综放工作面受采空区矸石充填程度的差异非均衡性,下端头充填密实,基本顶形成“倾向砌体”铰接结构,上端头基本顶作为规则冒落带随着割煤推进发生冒落,呈悬顶状态居多;基本顶向工作面正上方延伸扩展发生离层,中下部的上方区域离层量大于其他区域,顶板破断沿工作面倾斜呈起伏状。大倾角综放工作面顶煤层松软,支架后柱空顶显现严重,整体压力偏低,正常推采期间支架长期处于低阻力运行状态。大倾角综放工作面不同区域顶板来压频次和强度差异性较大,两端区域顶板来压频次和强度低于中部区域,工作面矿压显现呈现明显的“时-空-强”非对称特征。

The overburden fracture characteristics and strata pressure behavior law of the fully mechanized caving face in large dip angle are affected by factors such as large dip angle of inclination,“three soft”and other geological conditions,which are prone to problems such as support bottom drilling,coal wall instability and caving,roof leakage and collapse between supports,and support biting and falling,which seriously affect the safety production of the face.Taking the 5-101 fully mechanized caving face in Fenyuan Coal Industry as the research object,using the methods of physical similarity simulation experiment and field monitoring,this paper analyzes the characteristics of overburden rock movement and fracture,roof collapse step distance and strata pressure behavior law in the fully mechanized caving face in the highly inclined coal seam.The results show that the difference in the filling degree of gangue in the gob is uneven in the fully mechanized caving face with large inclination,the lower end is filled tightly,the basic roof forms a“inclined masonry”articulated structure,and the upper end basic roof,as a regular caving zone,falls with the advance of coal cutting,mostly in the form of suspended roof.The basic top extends directly above the working face,and delamination occurs.The amount of delamination in the upper area of the middle and lower part is greater than that in other areas.The roof fracture is inclined and undulating along the working face.The coal seam at the top of the fully mechanized caving face with large dip angle is soft,the hollow roof of the column behind the support appears seriously,and the overall pressure is low.During the normal push mining,the support is in a low resistance operation state for a long time.The frequency and intensity of roof pressure in different areas of the fully mechanized caving face with large dip angle are quite different.The frequency and intensity of roof pressure in both ends of the face are lower than that in the middle area.The ground pressure behavior of the face presents obvious“time space strength”asymmetric characteristics.