摘要
利用声发射技术监测受载混凝土裂缝发展特征的首要任务是对声发射源的准确定位。为了解混凝土中声发射波速特性,提高声发射源定位精度,该文开展了一系列室内试验,构建了考虑衰减现象的声发射波速修正模型,优化建立了基于修正波速的区域穷举定位法。结果表明:水灰比越小,基准波速越大,波速随距离的衰减越大。骨料粒径越大,基准波速越大,波速随距离的衰减越大。直线距离小于500 mm时,可采用对数函数描述声发射波速与距离的定量关系,以此构建的波速修正模型满足工程精度要求。采用修正波速的区域穷举定位法对单轴压缩试验产生的裂缝进行定位时,定位点比时差定位法更接近裂缝实际位置,有效提高了定位精度。
The primary task of monitoring the development characteristics of concrete cracks under load by acoustic emission technology is to accurately locate acoustic emission sources.In order to understand the character of acoustic emission in concrete and improve the positioning accuracy of acoustic emission source,a series of laboratory tests were carried out in this paper,a wave velocity correction model of acoustic emission considering attenuation phenomenon was constructed,and a regional exhaustive positioning method based on the corrected wave velocity was optimized.The results show that the smaller the water-cement ratio is,the larger the reference wave velocity is and the larger the attenuation of the wave velocity is with the distance.The larger the aggregate particle size is,the larger the base wave velocity is and the larger the attenuation of the wave velocity is with the distance.When the linear distance is less than 500 mm,the logarithmic function can be used to describe the quantitative relationship between acoustic emission wave velocity and distance,so that the wave velocity correction model constructed can meet the requirements of engineering accuracy.The location point is closer to the actual location of the crack than the time difference method,which can effectively improve the location accuracy when using the zone exhaustion method with modified wave velocity to locate the crack.
作者
李冬雪
杨康
何兆益
周翰林
LI Dongxue;YANG Kang;HE Zhaoyi;ZHOU Hanlin(Chongqing Jiaotong University,College of Tranffic&Transportation,Chongqing,400074,China;Chongqing Jiaotong University,School of Civil Engineering,Chongqing,400074,China)
出处
《应用声学》
CSCD
北大核心
2021年第3期400-406,共7页
Journal of Applied Acoustics
基金
国家重点研发计划项目(2018YFB1600200)。
关键词
混凝土
声发射
波速特性
源定位
Concrete
Acoustic emission
Wave velocity character
Localization
