羊场湾煤矿高强度开采工作面支架工作阻力确定方法

Determination method of support resistance in high-intensity mining face of Yangchangwan Mine

针对羊场湾煤矿多煤层开采过程中容易出现的顶板大范围切落问题,采用理论分析和数值计算手段分析了其发生的原因。受二煤开采影响,一煤及覆岩结构受到破坏,一煤回采期间顶板结构自身不能保持平衡,发生失稳,导致顶板灾害的产生;采场顶板单关键块运动轨迹表明来压期间工作面若高速推进,灾害发生的可能性增大,下层煤的开采导致上覆岩层受采动影响破坏程度大,增加了顶板单关键块结构滑落失稳的概率,引起顶板台阶下沉;根据控顶距的大小不同,单关键块结构可能出现自由落体式和回旋式2种失稳方式,并利用动载荷法分别计算了2种失稳模式下支架所承受的最大冲击作用力;工作面长度增加,导致基本顶之上的随动载荷大于简支条件下顶板的极限承载能力,顶板周边和中间断裂线同时出现,提高了工作面来压强度;最后采用数值计算方法验证了羊场湾煤矿120101工作面长度195 m的条件下,选取额定工作阻力9000 kN的液压支架是合理的。

Aiming at the large-scale roof cutting problem that was easy to occur in the process of multi-seam mining in Yangchangwan Mine,theoretical analysis and numerical calculation were used to analyze the causes.Affected by the second coal mining,the structure of the first coal and the surrounding rock was damaged,and the roof structure itself could not maintain balance during the first coal mining,resulting in instability and roof disaster.The movement trajectory of single key block in stope roof showed that if the working face was advanced at a high speed during the weighting period,the possibility of disasters increased.The mining of lower coal leaded to a large degree of damage to the overlying strata affected by mining,which increased the probability of sliding instability of the single key block structure of the roof and caused the roof step subsidence.According to the size of the control top distance,the single key block structure had two instability modes of free falling and rotary,and the dynamic load method was used to calculate the maximum impact force of the support under the two instability modes.With the increase of working face length,the dynamic load above the basic roof was greater than the ultimate bearing capacity of the roof under the simple condition,and the surrounding and middle fracture lines of the roof appeared at the same time,which improved the weighting strength of the working face.Finally,the numerical calculation method was used to verify that it was reasonable to select the hydraulic support with rated working resistance of 9000 kN under the condition that the length of No.120101 Face in Yangchangwan Mine was 195 m.