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超长工作面支架工作阻力分布及分区增阻特性研究

Study on working resistance distribution of support and resistance increasing characteristics of support partition in longwall face with ultra-large length

  • 摘要: 综采工作面倾向长度的增加,对顶板破断及应力演化产生的影响效应是复杂的,导致工作面支架支护特性存在分区差异。为深入理解超长工作面支架与围岩相互作用关系,以小保当煤矿450 m超长工作面为工程背景,构建弹性基础岩梁力学模型,运用数理统计及均化循环分析方法,对工作面支架实测数据开展循环末阻力、工作阻力分布频率、支架增阻特性分析,明晰不同面长工作面倾向方向顶板运动及支架工作阻力分布特征,探究超长工作面支架倾向分区内支架增阻特性。研究结果表明:工作面倾向长度增加,导致两巷煤体对中部顶板的支承减弱,中部峰值区域向两巷移近,超长工作面支架工作阻力分布趋势呈M型三峰值分布;超长工作面上部、中部、下部三区域支架呈对数型增阻时,其均化曲线仍为对数函数,表现为先急增阻后趋于平缓,此种支架增阻情况反映了来压期间工作面顶板由快速下沉逐渐变为缓慢下沉;呈对数−指数型增阻时,中上部区域支架增阻均化曲线为对数函数,中部及中下部均化曲线为对数−指数型复合函数,表现出先急增阻然后趋于平缓最后急增阻的特征;当支架工作循环时间超过一定值,对数−指数复合增阻型支架会急速增阻,不利于顶板控制,通过优化工作面割煤速度,降低支架工作循环时间,可减小支架增阻量,避免高阻力状态下支架再次瞬时增阻,提升工作面支架支护效果。

     

    Abstract: The effect of the increase of inclined length of fully mechanized mining face on roof breaking and stress evolution is complex, which leads to regional differences in the support characteristics of support in mining face. In order to deeply understand the interaction between support and surrounding rock in super-long working face, taking the 450 m super-long working face in Xiaobaodang Coal Mine as the engineering background, the mechanical model of elastic foundation rock beam is constructed, and the mathematical statistics and homogenization cycle analysis method are used to analyze the end-cycle resistance, working resistance distribution frequency and increasing resistance characteristics of support in working face. Clarify the characteristics of roof movement and support working resistance distribution in the inclined direction of working face with different face lengths, and explore the resistance increasing characteristics of support in the inclined zone of super-long working face. The results show that with the increase of the inclination length of the working face, the support of the coal body in the two roadways to the central roof is weakened, the peak area of the middle working face moves closer to the two roadways, and the distribution trend of working resistance of support in super-long working face is M-type three-peak distribution. When the support in the upper, middle and lower parts of the super-long working face shows a logarithmic resistance increase, the homogenization curve is still a logarithmic function, which shows that the resistance increases rapidly at first and then tends to smooth. The resistance increase of the support reflects that the roof of the working face gradually changes from rapid subsidence to slow subsidence during the pressure period. In the case of logarithmic-exponential drag increase, the resistance increase homogenization curve in the middle and upper region is a logarithmic function, and the middle and lower homogenization curve is a logarithmic-exponential compound function, which shows the characteristics that the resistance increases rapidly at first, then tends to smooth and finally increases rapidly. When the working cycle time of the support exceeds a certain value, the logarithmic-exponential compound resistance increasing support will rapidly increase the resistance, which is not conducive to the roof control. By optimizing the coal cutting speed of the working face and reducing the working cycle time of the support, the resistance increase of the support can be reduced, and the instantaneous resistance increase of the support in the state of high resistance can be avoided and the supporting effect of the support in the working face can be improved.

     

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