花岗岩分级加载过程中声发射及其分形特征分析  

Analysis of Acoustic Emission and Fractal Characteristics of Granite Under Step Loading

作　　者：侯奎奎 HOU Kuikui(Laboratory of Deep Mining of Shandong Gold Group Co.,Ltd.,Laizhou 261400,Shandong,China;Shandong Key Laboratory of Deep-Sea and Deep-Earth Metallic Mineral Intelligent Mining,Jinan 250000,Shandong,China)

机构地区：[1]山东黄金集团深井开采实验室,山东莱州261400 [2]山东省深海深地金属矿智能开采重点实验室,山东济南250000

出　　处：《矿冶工程》2024年第6期32-35,共4页Mining and Metallurgical Engineering

基　　金：山东省自然科学基金(ZR2021ZD36)。

摘　　要：针对花岗岩开展单轴分级加载声发射试验,分析了试样在失稳破裂前各保载阶段声发射频率、事件发生率及其分形维数演化特征。结果表明:花岗岩分级加载过程中,高频信号随着应力增大先减小后增加;试样在分级应力加载的最后一个保载阶段发生宏观失稳,该阶段试样内部微裂纹由稳定扩展阶段进入非稳定扩展阶段;试样失稳前各保载阶段,声发射事件发生率随着时间延长而逐渐降低,最后一个保载阶段,声发射事件发生率先降低后升高,岩石内部非稳定性破裂增加,微裂纹逐渐合并、贯通,形成宏观裂纹,进而引发试样的整体失稳破坏;随着应力增大,声发射分形维数呈现先升高后降低的趋势,岩石破裂逐渐从无序向有序发展。An acoustic emission(AE) test of granite under uniaxial step loading was carried out,and the evolution characteristics of AE frequency,event incidence and fractal dimension of the sample at each load-holding stage before occurrence of instability and fracture were analyzed.The results show that the high-frequency signal first decreases and then increases with the increase of stress in the process of step loading;and macro-instability occurs in the sample at the last stage of step loading,at which the internal micro-cracks in the sample undergo from stable propagation to unstable propagation.The incidence of acoustic emission events decreases gradually as time is prolonged.At the last stage of step loading,the incidence of acoustic emission events decreases first and then increases,unstable fracture in the rock increases and micro-cracks gradually merge and coalesce to form macro-cracks,resulting in overall instability and fracture of the sample;with the increase of stress,the fractal dimension of acoustic emission decreases after an initial increase,and the rock fracture develops gradually in an order way from a disorder way.

关 键 词：花岗岩 分级加载 声发射 岩石力学 分形特征 频谱分析 分形维数 

分 类 号：TD313[矿业工程—矿井建设]