基于利兹法的煤壁破坏机理分析及三维相似模拟试验研究

Longwall face stability analysis using Ritz method and its 3D physical modelling study

针对严重影响大采高工作面生产和安全的煤壁片帮问题,提出了采用能量原理中基于位移变分原理的利兹法分析煤壁破坏机理,并利用煤壁稳定性三维相似模拟实验平台研究"顶板-支架-煤壁"系统的协调变形规律。结果表明:基于利兹法的煤壁破坏机理模拟出了煤壁上部片帮、上下部同时片帮、整体片帮3种现场常见的煤壁片帮形态,煤壁稳定性的重要影响因素确定为煤体黏聚力、煤壁集中力、煤壁弯矩、顶板载荷等;在煤壁集中力和煤壁弯矩的作用下,顶板下沉近似呈直线增长,顶板下沉速率和煤壁水平变形速率大,煤壁在短时间内发生整体片帮,并具有突发性;在支架的支护作用下,顶板呈现阶梯式下沉规律,顶板下沉速率和煤壁水平变形速率显著减小,煤壁表面仅出现局部破碎,煤壁在较长时间内保持了一定的稳定性。

Face fall remains one of the most difficult ground control problems in single-pass thick seam longwall mining which affects the safety and production. The mechanism of face failure is analyzed using Ritz method,and the co-deformation characteristics of the ＂roof-support-face＂system are revealed through the 3 D physical modeling study. The results show that：（1） The proposed face failure mechanism based on Ritz method simulates the top face fall,top and bottom face fall and entire face fall that are typically observed in the field,and the important influencing factors on face failure are determined as coal cohesion,face concentrated load,face movement and roof uniformly-distributed load.（2） The physical model shows that entire face falls occur in a short time under the concentrated load and face movement.The roof displaces linearly in the vertical direction. Roof vertical displacement and face horizontal displacement increase at a large rate.（3） Under the protection of roof support,however,only partial face failure is observed on the face.The roof vertical displacement increases in a step function.The increase rates of the roof and face displacement are significantly reduced.Face maintains its stability in a relatively long time.