顶板冲击载荷作用下巷道支护体系动力响应特征研究

基于某矿实际地层分布与巷道支护情况,建立了全围岩煤矿巷道和邻近采空区巷道的动力学数值模型,分析了巷道上方不同位置冲击动力下巷道围岩和支护体系的动力响应规律以及邻近采空区小煤柱护巷对巷道支护防冲的影响。研究结果表明:巷道正上方坚硬顶板冲击动力下,巷道直接顶围岩质点运动速度和冲击力最大,随着冲击动力源沿顶板展布方向偏离巷道中线距离的增大,巷帮质点运动速度和加速度逐渐增大,在偏离中线约60 m时,巷帮质点运动速度和加速度值达到最大值,而冲击动力源偏离中线距离大于60 m后,巷帮质点运动速度和加速度值逐渐减小。此外,巷道上方顶板冲击下,巷道锚杆中段应力变化幅值最大,随着顶板冲击源偏离巷道中线距离增大,巷道潜在破坏的锚杆位置由巷帮向顶板区域转移。临近采空区巷道情况下,采空区上方顶板冲击会引起巷道帮部质点产生较大的质点加速度,并造成巷帮和小煤柱中锚杆失效,而远离采空区并偏离巷道中线60 m之外的顶板冲击下,采空区对巷道支护体系动力响应的影响较小。

Numerical modelling on dynamic response of roadway supporting system induced by roof bursting waves

According to the real rock stratum and supporting of coal roadway,the dynamic numerical model of a coal roadway without goaf and a roadway nearby roadway were established.Analysis on the dynamic response of the confining rock and supporting system of coal roadway was conducted considering the different locations of dynamic source origin from the upper hard roof,the influence of small coal pillar near the goaf on the rock bursting prevention of a coal roadway was also evaluated.As a result,the mass in the direct roof of a coal roadway has the largest velocity and acceleration when the dynamic source comes from the right above roof,the velocity and acceleration at the side wall were increased by the increasing offset distance of dynamic source from the center line of a coal roadway,in the case of 60 m,the side wall of roadway has the largest velocity and acceleration,but were decreased when the offset distance overpass 60 m.During the vibration process,the middle parts of rock bolts have the largest dynamic amplitude of stress,and potential fail rock bolts located in the side wall but changed to the direct roof with the promoted offset distance of dynamic source.In the case of a coal roadway nearby goaf,the dynamic source from the roof above goaf will cause a large horizontal acceleration at the side wall of roadway,seriously,inducing fracture in coal bolts in both side wall and coal pillar.Whereas if the dynamic source comes from the roof 60 m away from the center line of coal roadway and beyond the side above goaf,the dynamic response of coal roadway and its supporting system were limited influenced by goaf.