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以多种岩石循环加卸载声发射试验为基础,针对岩石损耗比和加卸载响应比特性进行了研究,探索岩石在受载过程中的内部损伤演化和破坏前兆特性。结果表明,在循环加卸载下角岩等三种岩石损耗比变化特性一致:低应力水平阶段损耗比较大,呈明显下降趋势;中等应力水平阶段比值下降趋势较平缓;高等应力水平阶段比值趋于稳定,在0.08~0.10时,试样破坏。而钨钼矿等三种岩石加卸载响应比变化特性一致:低应力水平阶段卸载时几乎没有声发射,加卸载响应比较大;中等应力水平阶段卸载时声发射较活跃,比值下降至1左右;高等应力水平阶段卸载时声发射很活跃,当比值重新大于1时,试样破坏。试验结果都体现了岩石内部损伤从很小到稳定扩展再到不稳定扩展的过程。可见,损耗比和加卸载响应比的变化特性均可用于评价岩石损伤情况,也可用作岩石破坏预测的参考依据。
Based on a variety of rock-loading and unloading acoustic emission tests, the rock loss ratio and loading / unloading response ratio characteristics were studied to explore the internal damage evolution and damage precursory characteristics of rocks during loading. The results show that the loss characteristics of three types of rocks, such as angle rock, are similar to those under cyclic loading and unloading: the loss in the low stress level phase is relatively large and decreases obviously; the ratio of medium stress level decreases gently; the ratio of higher stress level tends to be stable , 0.08 ~ 0.10, the sample damage. The loading and unloading responses of the three types of rocks, such as tungsten and molybdenum, are similar to those of the unloading response: there is almost no acoustic emission during unloading at low stress level, and the loading and unloading response is relatively large. Acoustic emission is more active during unloading at medium stress level, The acoustic emission is very active during unloading at the higher stress level. When the ratio is greater than 1, the sample is destroyed. The test results all reflect the process of rock internal damage from small to stable expansion to unstable expansion. It can be seen that the change characteristics of loss ratio and loading-unloading response ratio can be used to evaluate the rock damage, and can also be used as a reference basis for rock failure prediction.