临空面对破碎锤冲击破岩效果的影响研究

Study on the Effect of Free Surface on Rock Breaking Effect by Impact of Hydraulic Breaking Hammer

为深入研究液压破碎锤冲击机理,利用自行设计的冲击试验装置展开试验,结合有限元-离散元耦合方法分析其在临空面辅助作用的破坏特性。试验结果表明:在临空面辅助作用下,岩石破坏强度得到劣化,冲击峰值力随临空面距离的增加呈先增加后稳定趋势,且在保持临空面距离不变情况下与冲击能量不相关;破岩比能耗随临空面距离的增加呈先下降后上升趋势;为达到最优破岩比能耗,临空面距离应选取能使岩石经一次冲击即可完成劈裂破坏时的最大值。研究结果为高效破岩提供了理论依据。

In order to deeply study the impact mechanism of hydraulic breaking hammer,the experiment is carried out by using the self-designed impact test device,and the failure characteristics of its auxiliary action on the free surface are analyzed by combining the combined finite and discrete element method.The test results show that the failure strength of rock is degraded under the auxiliary action of free surface,the peak impact force increases first and then stabilizes with the increase of the free face distance,and is not related to the impact energy while keeping the free face distance unchanged;the specific energy consumption of rock breaking decreases first and then increases with the increase of the distance from the free face;in order to achieve the optimal specific energy consumption of rock breaking,the distance from the free surface should select the maximum value that can make the rock complete splitting failure after one impact.The research results provide a theoretical basis for efficient rock breaking.