预制缺陷对花岗岩层裂破坏的影响

摘要

利用50 mm杆径的霍普金森压杆装置对完整和预制缺陷花岗岩试样进行层裂破坏实验,并采用高速摄像仪记录了试件层裂破坏的全过程.通过理论分析,计算了半正弦波加载情况下完整杆可能的初始层裂位置.高速摄影结果显示,预制缺陷对初始层裂位置具有一定影响,层裂一般发生在预制缺陷处.结合PFC2D(particle flow code in two dimensions)数值模拟进一步发现,初始层裂位置受到预制缺陷和反射拉伸波上升沿的影响,反射拉伸波上升沿越长,初始层裂越可能发生在预制缺陷处,反射拉伸波上升沿越短,初始层裂位置发生在预制缺陷处的可能性则相对越小.%The intact and pre-existing flaw granite specimens were tested by using the split Hopkinson pressure bar device with 50 mm rod diameter,and the whole process of spalling fracture was recorded by a high-speed video camera.Based on the theoretical analysis,the possible initial spalling positions of the granite specimens under half sine wave loading were calculated.The results of high-speed photography show that the pre-existing flaws have certain influence on the initial spalling positions,and spalling fractures generally occur at pre-existing flaws.According to the PFC2D (particle flow code in two dimensions) model,it is found that the initial spalling positions are influenced by the pre-existing flaws and the rising edge of the reflected tensile wave.The longer the rising edge of the reflection wave,the more likely the initial spalling occurs at the pre-existing flaw.The shorter the rising edge of the reflected tensile wave,the less likely the initial spalling occurs at the pre-existing flaw.