不同速率下松散颗粒直剪试验声发射特征  

Acoustic Emission Characteristics of Loose Particles in Direct Shear Test at Different Rates

作　　者：吴鑫[1,2] 罗筱毓 李龙灿 刘永红 朱旭 林华李 WU Xin;LUO Xiaoyu;LI Longcan;LIU Yonghong;ZHU Xu;LIN Huali(College of Engineering,Sichuan Normal University,Chengdu 610101,China;State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川师范大学工学院,四川成都610101 [2]四川大学水利学与山区河流开发保护国家重点试验室,四川成都610065

出　　处：《西南交通大学学报》2025年第1期128-136,共9页Journal of Southwest Jiaotong University

基　　金：国家应急管理部安全生产重特大事故防治关键技术项目(sichuan-0011-2018AQ);四川省科技计划项目(24NSFSC0343,19YYJC2854)。

摘　　要：松散颗粒堆积体在自然界和工业生产活动中广泛存在.为研究其力学性质和失稳过程,基于声发射(acoustic emission,AE)技术探究松散体剪切过程的声学特征演化规律.首先,分析松散颗粒在不同剪切速率下的AE特征参数;其次,结合加载过程的力学特征对AE演化阶段进行划分;最后,利用频谱变化和小波包能量占比进一步验证松散颗粒剪切破坏的AE演化规律.结果表明:能量和振铃计数随剪切过程而逐步增大,且剪切速率越快,能量和振铃计数增幅越大;小事件数与大事件数的比值(b值)在剪切过程中逐渐降低,剪切速率越大,b值越小;不同速率下的颗粒抗剪强度约为140kPa,剪切力峰值集中在400N左右,振铃计数、AE能量与b值在剪切运动过程中的变化与剪切破坏阶段密切相关;频谱重心会随剪切过程逐步降低,从大约350 kHz降低至250kHz,同时,较低频带能量占比增加、较高频带能量占比减少,导致频谱重心不断下移.Loose particle accumulations are widely present in nature and industrial production activities.In order to study their mechanical properties and instability processes,acoustic emission(AE)technology was used to explore the evolution law of acoustic characteristics of loose particles in a shear process.Firstly,the AE characteristic parameters of loose particles at different shear rates were analyzed.Then,the AE evolution stages were divided based on the mechanical characteristics of the loading process.Finally,the AE evolution law of loose particles under shear failure was further verified with spectral changes and the proportion of wavelet packet energy.The results show that the energy and ringing count increase gradually with the shear process.The faster the shear rate,the larger the increases of energy and ringing count.The number ratio of small events to large events(b value)decreases gradually during the shear process,and the larger the shear rate,the smaller the b value.The shear strength of particles at different rates is about 140 kPa,and the peak shear force is about 400 N.The changes of ringing count,AE energy,and b value during shear motion are closely related to shear failure stage.The spectral barycenter gradually decreases in the shear process from about 350 kHz to 250 kHz.Meanwhile,the energy proportion of the low frequency band increases,and the energy proportion of the high frequency band decreases accordingly,which results in a spectral barycenter constantly moving down.

关 键 词：松散颗粒 剪切速率 声发射 频谱分析 小波包分解 

分 类 号：X936[环境科学与工程—安全科学]