基于声发射参量的不同深度灰岩塑性破坏识别研究

对某矿深部灰岩进行单轴压缩试验,测得试件破坏全过程的应力、应变和声发射参数。通过分析应力、应变和声发射参数之间的关系,可根据声发射振铃计数率的变化情况,将全过程分为三个阶段:第一阶段处于孔隙裂隙压密阶段,振铃计数率较多;第二阶段处于稳定变形阶段,声发射处于平静期;第三阶段岩石进入塑性变形阶段,振铃计数率明显增加。研究发现,深度越深,第一阶段终止时的应力水平越高;将声发射累计能率与累计振铃计数率的比值定义为能振比λ,λ的变化规律一定程度上反映出试件内部裂隙发展情况。研究λ的变化规律能够为识别岩体失稳提供依据,提高声发射技术监测预报的准确性。

On the Plastic Damage Identification of Limestone from Different Depths Based on Acoustic Emission Parameters

Uniaxial compression experiment of deep limestone taken from a mine was carried out,the stress,strain and acoustic emission parameters of specimen in whole failure process were measured.Through analysis of relation among stress,strain and AE parameters,the whole failure process may be divided into three stages according to the variation of AE count rate:the first stage is a pore and fissure compaction stage,there is more counting rate;the second stage is a stable deformation stage,AE is in a quiet period;in the third stage,rock enters plastic deformation and counting rate is increased significantly.Study reveals that with the increase of depth,the stress level in the first stage becomes higher.The ratio of cumulated AE energy rate and cumulated count rate is defined as energyvibration ratio λ,the variation of which reflects at certain degree the development of internal crack in specimen.The variation of λ is able to provide evidence for identifying the instability of rock mass,therefore to improve the accuracy of acoustic emission monitoring and forecasting.