应力波作用下岩石声发射能量特征

通过霍普金森(SHPB)实验系统,对应力波作用下岩石破坏进行声发射实验,获得了该加载条件花岗岩声发射能量的变化规律.实验结果表明,声发射能量变化呈现出两种明显不同的特征:I型,声发射峰值能量之后,能量迅速衰减,到加载的末期,能量出现一定的回升,产生“拐点”;Ⅱ型,声发射峰值能量之后,能量衰减相对Ⅰ型较慢,且不出现“拐点”.通过对岩石破碎块度的分析,得到了声发射峰值能量与岩石破碎分维之间的关系.本文的研究有助于重新寻求应力波下岩石破坏的声发射前兆规律.

On the Acoustic Emission (AE) Energy Characteristics of Rock Subjected to Stress Waves

Acoustic emission experiment of rock failure subjected to stress waves was carried out based on SHPB (split Hopkinson pressure bar) experimental system. The variation of acoustic emission energy of granite subjected to this loading was obtained. Experimental results show that the variation of AE energy presents two different features: mode I, energy decays rapidly after peak value, however, at the end of the loading, energy rises and "inflection point"appears; mode II, energy decays slowly after peak value, but no "inflection point"appears. Through analysis of rock fragmentation, relation between the AE peak energy and the fractal dimension value is obtained. Above results may be helpful to both theory and practice for seeking precursory characteristics of AE of rock mass subjected to stress wave.