岩石循环冲击损伤演化围压效应的实验研究

为研究岩石循环冲击荷载作用下损伤的围压效应，对大理岩试件在压力试验机上进行模拟冲击加载，测试受冲击后试件轴向超声波波速。用超声波波速变化量描述试件的损伤度。分析了围压、荷载冲量大小、冲击次数对岩石损伤演化的影响，得出了大理岩在不同围压下冲击损伤与冲击次数的函数关系。分析了大理岩岩样循环冲击损伤的围压效应。结果表明，岩石循环冲击损伤具有明显的围压效应，围压的存在提高了岩石抗冲击破坏的能力。从试验角度证明了在深部矿井中高地应力的存在对钻孔的钻进效率和处于初始应力场中的岩石的爆破破碎效率有重要影响。

Experimental Study on Confining Pressure Effect of Rock Damage Under Cyclical Impact Loading

Three groups of experiments have been designed so as to analyze the confining pressure effect of rock under the action of cyclical impact loading. Marble testing-cylinders were put on the pressure testing - machine to simulate impact loadings. The axial velocities of ultrasonic wave in damaged marble testing - cylinders were actually measured. The variation of ultrasonic velocities was used to describe the damages degree of rock under cyclical impact loading. Then after analyzing effects of confining pressure, impulsive force and time of shock on the damage degree of rock, the function between shock damage and times of shock under different confining pressure were obtained. Furthermore, the confming pressure effect of marble rock damaged under cyclical impact loading was also analyzed in the experiments. Results show that rock damaged under cyclical impact will obviously bring confining pressure effect, and the existence of confining pressure also increased the ability of rock against impact damage. It is proved that the existence of high ground stress in the deep of shaft will have an important impact on the advancement of drill hole and blasting efficiency of the rock in initial stress field.