静载与冲击加载方式下滚刀破岩特性

摘要

In order to research the disc cutter cutting mechanism under static loading and impact dynamic loading conditions, a two-dimensional numerical simulation method with which disc cutters break rock was established based on the particle discrete element method. Stress boundary condition was considered instead of velocity boundary condition. The dynamic process of breaking rock under constant static loading and impact dynamic loading was analyzed. The effects of load and impact cycle numbers on the characteristics of breaking rock were studied. Finally, an experiment was carried out on the linear experiment platform. The results show that the increase of static load can improve the rock fragmentation effects under constant static loading. When static load reaches a certain value, the rock fragmentation effects change inconspicuously and there is a optimal value which makes the rock fragmentation effects best. Under impact dynamic loading, the rock crack propagation behavior is similar to that under static loading, but the rock is prior to shear failure. With the increase of dynamic load and frequency, the number of rock cracks increases and the specific energy consumption decreases and then changes little. Meanwhile, the rock cracks tend to penetrate rock free surface. The variation trend of the specific energy consumption under constant static loading is consistent with that under cyclic impact dynamic loading and the former is 1.4 times of the latter.%为了研究在单一恒定静载荷和冲击动载荷这2种情况下盘形滚刀破岩机制,使用颗粒离散元法建立滚刀破岩的二维数值模型.通过控制破岩的垂直载荷,对滚刀破岩动态过程进行分析并研究静载荷、冲击动载荷和冲击次数对滚刀破岩特性的影响,最后通过实验对静载荷下滚刀破岩情形进行验证.研究结果表明:在单一恒定静载荷下,滚刀破岩效果随着静载荷增大而提高;当静载荷达到一定值后,破岩效果提升不明显,存在1个最佳静载荷使破岩效果最优;在冲击动载荷作用下,岩石裂纹扩展情况与静载荷的扩展情况相似,但岩石内部以剪切破坏为主;随着循环冲击动载荷以及施加次数增大,岩石内部产生的裂纹数增大并且有向水平贯穿的趋势,破岩比能耗先减少后变化不大;滚刀在动静载荷作用下比能耗的变化趋势基本一致,冲击动载荷破岩的比能耗比静载荷作用下的比能耗高,大约是静载荷破岩比能耗的1.4倍.