大倾角煤层长壁开采工作面飞矸致灾机理研究

摘要

飞矸是大倾角煤层一类特殊衍生灾害,严重危害工作面设备和人员的安全,探讨其致灾机理对建立大倾角煤层走向长壁工作面防护体系至关重要.在工作面飞矸灾害实测基础上开展实验室模拟,选取冲击能和能量恢复系数表征损伤,借助高清摄像机和压力传感器记录并获取冲击能;运用统计学原理分析不同工况下冲击能的演化特性;对冲击能和能量恢复系数拟合并根据曲线走势,以设备(人员)吸能量为控制对象,吸能量陡增点和极值点为界建立飞矸损伤风险判别模型,依据模型划分飞矸损伤的等级.基于以上探讨了飞矸致灾的机理,结果表明:飞矸致灾是在碰撞途径和方式耦合作用下冲击能和能量恢复系数达到相应致灾等级,致灾过程为自由落体、飞溅、滚动和滑动等状态下冲击能累积,满足走向运移、高度、碰撞方位后与设备接触,冲击能转化为设备弹性能和构件间振动阻尼,造成构件的形变量大于其极限形变量时发生损坏,数值仿真手段验证了理论和实验研究中能量恢复系数取值的合理性.%The flying gangue is a kind of special derivative disaster in the steeply dipping coal seam,which seriously endangers the safety of the working face equipment and personnel.It is essential to discuss the disaster mechanism to establish the protection system in longwall face along strike when mining the steeply dipping coal seam.Laboratory simulation was carried out on the basis of disaster measurement of flying gangue,the impact energy and energy recovery coefficient were used to characterize the flying gangue's hazard,impact energy were recorded and acquired by HDV and pressure sensors.The evolution characteristics of impact energy under different working conditions were analyzed by statistical principle.The risk discrimination model of flying gangue was established according to the curve of impact energy and energy recovery coefficient,and the damage level of flying gangue were divided.Then taking the energy of equipment (personnel) as the control object,the energy absorption steep point and extreme point as the boundary,the flying gangue damage risk discrimination model was established to divide the damage level.The mechanism of flying gangue disaster was discussed on the basis of above discussion.The results show that the hazard of flying gangue by the impact energy and energy recovery coefficient reaches to the corresponding hazard level under the coupling of collision path and mode.The disaster process is the accumulation of impact energy in the state of free fall,splash,rolling and sliding,meets the movement,height,collision position and contact with the equipment.The impact energy can be converted into the elasticity of the device and the vibration damping between the components,resulting in the deformation of the component is greater than its ultimate deformation when the damage occurs.Lastly,the rationality of the energy recovery coefficient in the studies of theory and experiment were verified by simulation method.