冲击荷载下平行双裂隙演化的颗粒流分析

为了研究冲击荷载下平行双裂隙对岩石破坏的影响，采用二维颗粒流程序对分离式霍普金森杆一维冲击试验进行模拟。对预制平行双裂隙倾角为0°、15°、30°、45°、60°、75°、90°和完整的花岗岩试样进行冲击加载模拟，全面研究了平行双裂隙试件裂纹的萌生、扩展、贯穿的过程。结果表明：在冲击荷载的作用下，平行双裂隙明显降低了岩石强度。裂隙存在时，裂隙倾角与加载方向一致时，试样峰值强度和起裂强度均达到最大，呈劈裂拉伸破坏模式，在倾角为45°左右达到最小值，呈拉剪复合破坏模式。预先存在缺陷的倾角对裂纹萌生和扩展模式有很大影响。对应力场分析，平行双裂隙对应力波的传播产生阻碍，在岩桥区域变化最为明显。

Particle Flow Analysis of Parallel Double Crack Evolution Under Impact Load

To study the effect of prefabricated parallel fissure granite under impact loads, the numerical model of split Hopkinson pressure bar was established by Particle Flow Code in 2 Dimensions, and the failure process of prefabricated parallel fissure granite with different dip angles (0°, 15°, 30°, 45°, 60°, 75° and 90°) was simulated. The process of crack initiation, propagation and penetration in paralled double-crack specimesns is studied in detail. The results show that the rock strength is obviously reduced when specimen with parallel double fractures is under the impact load. When the angle is consistent with the loading direction, the peak strength and crack initiation strength of the sample reach the maximum, showing splitting tensile failure. And the minimum value occurred at the angle of 45°, showing combined tensile-shear failure. It is found that the flaw angle of prefabricated parallel fissure has a great influence on the crack initiation and propagation mode. The analysis of stress field shows that the prefabricated parallel fissure hinder the propagation of stress waves, especially in the rock bridge area.