不同硬岩破裂失稳声发射及b值动态特征实验研究

为了研究不同硬岩破坏过程中声发射及b值演化特征差异,在单轴加载条件下对不同种类硬岩进行声发射实验,得到不同种类硬岩破裂失稳过程中的力学特征,分析了不同种类的硬岩声发射能量率变化特征。并基于振幅与震级之间幂律关系定义声发射b值,对比了不同硬岩破裂失稳过程声发射b值演化特征,并分析了应力水平与声发射b值演化关系。研究表明:高强度、高脆性系数的岩石,从本构关系来看,没有明显屈服点,声发射能量率量级也越大;各试件在临近破坏时的声发射b值均大幅度下降,但花岗岩下降幅度最大。

Experimental investigation on acoustic emission and b-value dynamic characteristics of different hard-rock failure

In order to investigate the difference of acoustic emission and b-value dynamic characteristics in different hard-rock failure process, the acoustic emission experiments of different hard-rock were carried out under uniaxial loading, the stress-strain curves in the process of failure were obtained, and the dynamic characteristics of acoustic emission energy rate were analyzed and compared. The b-value was calculated based on the power law relation between amplitude and magnitude; the evolution characteristics of b-value during different failure processes were compared. The relational about stress level and b-value was analyzed. The results show that the yield points of rock with high strength and brittleness are not obvious, and the magnitude of the AE energy rate is bigger. The b-values of all rock samples began to decrease when they were fracture, but the decline of granites were greatest. The combined analysis of the acoustic emission energy rate and the b-value can provide a new idea for the prediction of hard-rock burst.