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利用自主研发的真三轴岩爆刚性试验机,对粗晶粒花岗岩试件开展应变型岩爆弹射破坏过程试验研究。设计不同的加载与卸载路径,模拟能量集聚驱动型与应力集中驱动型2类岩爆的弹射破坏过程,在借助高速摄像系统对岩石碎块弹射过程进行影像记录与速度测量的基础上,分析岩爆弹射破坏过程的特征与规律。研究结果表明:(1)岩爆弹射破坏过程可概括为颗粒弹射、劈裂成板、剪切成块、板折弹射4个阶段;(2)弹射破坏后的岩样母体具有二元破坏形态,即临空面出现V形或台阶状的岩爆坑,而岩身内侧出现贯穿性剪切裂缝;(3)加载速率对应力集中驱动型岩爆具有重要影响,在0.05~2 MPa/s加载速率范围内,弹射动能随加载速率增大而增大;(4)峰前集聚的弹性应变能足够大且能量输入速率足够大是岩样发生应力集中驱动型岩爆的基本条件;(5)无论是能量集聚驱动型岩爆,还是应力集中驱动型岩爆,弹射动能占岩样峰前可释放弹性应变能的比例不足1%。
The self-developed true triaxial rock burst rigid testing machine was used to test the strain-induced rock burst projectile failure process on the coarse grained granite specimens. Different loading and unloading paths were designed to simulate the catastrophic destruction process of Class 2 rockburst driven by energy concentration and stress concentration. Based on the image recording and velocity measurement of the rock ejection process with high-speed camera system, The Characteristics and Rules of Explosion Projectile Damage Process. The results show that: (1) The rock burst destruction process can be summarized as particle ejection, splitting into plates, shearing into blocks and bouncing shells. (2) The rock samples after ejection failure have binary failure modes , That is, there are V-shaped or stepped rock burst pits in the chaotic surface and through shear cracks in the inner side of the rock mass. (3) The loading rate has an important influence on the stress-driven rock burst, and at 0.05-2 MPa / s (4) The elastic strain energy accumulated before the peak is large enough and the energy input rate is large enough, which is the basic condition for rock-stress-driven rockburst to occur. (5) Either energy-driven rock burst or stress-driven rock burst, the proportion of ejection kinetic energy that can release elastic strain energy before the peak of rock sample is less than 1%.