特厚煤层综放工作面大面积切顶压架原因分析

Reason analyses on large area roof cutting and collapse of hydraulic supports at fully-mechanized top coal caving mining face in ultra thick coal seams

基于"悬臂梁-铰接岩梁"岩层结构和Winkler地基理论,分析了该类事故的发生原因,并相应地给出防治对策。研究结果表明:大面积压架主要特征是工作面顶板在煤壁处切落,直接顶和基本顶失去横向平衡;切顶发生的原因在于初撑力和工作阻力较低,难以维系直接顶和基本顶平衡结构。通过提高支架初撑力,以增加支架对顶板的主动支撑能力,减少顶板下沉量,有利于直接顶和基本顶的平衡结构;基于"悬臂梁-铰接岩梁"岩层结构模型分析认为,崔木煤矿工作面支架工作阻力不足是导致大面积压架事故的主要原因,并经理论计算得出合理工作阻力为15 000 k N。

Based on rock structure of cantilever rock beam & hinged rock beam and the Winkler foundation model,this paper analyzes the causes of large area roof cut and collapse of hydraulic supports,which occurs frequently at fully-mechanized top coal caving working faces in super thick coal seams. Then the paper proposes the measures to prevent and control such accidents. According to studies,hydraulic supports are crushed down and collapsed in large area by roof cutting down at the coal wall in the working face,which makes the immediate roof and the basic roof lose their horizontal balance. The reason of roof cutting tends to be low levels of setting load and weak working resistance of the hydraulic supports,and accordingly they can hardly sustain the balance structure of immediate roof and basic roof. By increasing setting load of the supports,their initiative support to the roof can be strengthened,and the sinking of roof can be lessened,thus being helpful to the balance of immediate roof and basic roof. Through analysis with cantilever rock beam & hinged rock beam rock structure,large area of support collapse at Cuimu Coal Mine was due to the lack of working resistance of hydraulic supports at the working face.The paper proposes through theoretical calculation that the working resistance should have been 15 000 k N.