大倾角松软煤层综放工作面支架倾倒机理研究

Study on tipping mechanism of hydraulic powered support applied in fully mechanized top coal caving mining face with high inclined soft seam

基于大倾角松软煤层综放工作面回采过程中支架倾倒频发的工程实践难题,采用现场监测与理论分析相结合的方法对支架倾倒的特征及影响因素进行了研究,并通过建立支架临界倾倒力学模型对支架临界倾倒状态进行了分析。结果表明:在工作面倾斜方向,工作面上部第50号支架空载率达48.26%、循环内载荷减少率达90%、倾倒次数达21次、平均倾倒角度达19°,这些指标均明显大于中部及下部支架;沿倾斜方向自下而上放煤时支架平均倾倒角度为11.3°,自上而下放煤时支架平均倾倒角度为5.7°。支架的稳定性依次为下部、中部、上部;松软顶煤的破碎漏冒以及在倾斜方向的滑移滚动是支架倾倒的主要原因;顶煤的载荷传递能力系数越小支架发生倾倒的可能性越大。

Based on the engineering practice difficulty of the powered support tipping frequently occurred in the mining process of the fully mechanized top coal caving mining face in the high inclined soft seam,a site monitoring and measuring and theoretical analysis combined method was applied to the study on the powered support tipping features and influence factors. With the establishment of the critical tipping mechanics model of the powered support,an analysis was conducted on the critical tipping status of the powered support. The results showed that at the inclined direction of the coal mining face,No. 50 powered support at the top section of the coal mining face had a unloading rate up to 48. 26%,a loading attenuation rate up to 90% in the circulation,a tipping number up to 21 times and average tipping angle up to 19°. Those indexes were obviously higher than the powered supports at the middle and low sections of the coal mining face. Along the inclined direction and during the top coal caving period from the low to top,the average tipping angle of the powered support was11. 3°and during the coal caving period from the top to low,the average tipping angle of the powered support was 5. 7°. The stability of the powered supports was at the low section,middle section and top section of the coal mining face in sequence. The soft top coal broken and falling and the sliding rolling in the inclined direction were the main causes of the powered support tipping. More the load transmission coefficient of the top coal was and higher possibility of the powered support tipping would be.