单轴压缩盐岩声发射特征及损伤演化探讨

为了探究盐岩压缩变形破坏过程中,声发射现象与内部损伤的相关关系,利用四川大学MTS815岩石力学试验系统,对云南安宁盐岩进行单轴压缩试验,分析了盐岩声发射特征。依据损伤理论,得到了基于声发射参数的盐岩的损伤演化模型,并引入修正系数对其进行理论修正,分析损伤终值对损伤本构模型的影响。研究结果表明:盐岩的声发射(acoustic emission,简称AE)振铃计数率和能量率在弹性极限附近达到最大值,之后呈现高频低幅值的声发射现象;基于声发射的盐岩损伤变量值在压缩变形前期增加较快;基于AE累计振铃计数得到的损伤值<基于AE累计能量计算得到的盐岩损伤值;修正后的声发射损伤理论模型曲线与试验曲线全过程吻合较好,能够较好地反映盐岩内部损伤演化过程;振铃计数参数模型比能量参数模型能更好地模拟盐岩的损伤演化特征。

Acoustic Emission Characteristics and Damage Evolution of Rock Salt under Uniaxial Compression

In order to explore the relation between acoustic emission phenomenon and internal damage in the failure process of compression deformation of rock salt, we conducted uniaxial compression test on salt rock from Anning, Yunnan province using MTS815 rock mechanics test system of Sichuan University. The damage evolution model of rock salt was established with acoustic emission parameters based on damage theory and the damage variable D was modified by coefficient of correction. The research results show that the maximum values of ring count rate and energy rate appeared near the elastic limit and the phenomenon of high frequency and low amplitude appeared later; the damage value based on AE increased rapidly in the early stage of compressive deformation, and the damage value based on AE accumulated ring counts is smaller than that based on cumulative energy; the revised damage model curve is in agreement with the whole process of test curve and could reflect the damage evolution process of rock salt well.Simulation using ring count can reflect the damage evolution characteristics of rock salt better than using energy.