摘要
声发射技术作为一种现代无损检测技术,能简便快捷地判别混凝土在受力状态下内部缺陷的产生与发展,是混凝土材料断裂力学研究的重要分析手段和有效的评价途径。文章首先阐述了声发射技术在混凝土检测领域的国内外研究与应用现状,特别是在大坝混凝土领域的研究进展。课题组通过改进现有试验装置和更新改造测量设备,将声发射检测系统引入混凝土双K断裂参数试验中,新装置不仅能够精确控制试验中的加载速率,而且可以实时监测试件的起裂状态,能够准确判断试件的开裂和失稳破坏的时刻和特征。文章根据混凝土断裂临界状态的声发射识别特征,建立了混凝土断裂的声发射判据。试验结果表明,利用声发射特征参量可以准确判断试件的起裂时刻,与传统的应变法测量的起裂时刻吻合的较好,并且这种判据更加直观,便于现场操作,从而为声发射技术在混凝土断裂参数的测试中应用提供了理论与技术支撑。
Acoustic emission is a modern non-destructive testing technique that is important to effective analysis and evaluation of concrete fracturing,and it can be easily used to monitor the internal defects of concrete material.This paper examines the recent progress of acoustic emission in the field of concrete structure,focusing on its application to concrete dam study,and presents our new results.In this study,the acoustic emission system used concrete fracture parameters to control the experiments.Through the improved system,accurate loading rate control and real-time monitoring of cracks development were successfully done for accurate judgment of specimen cracking and real-time development of instability and failure.Acoustic emission criterion of concrete fracturing was established using the acoustic emission parameters at the critical state of fracturing.Experimental results show that with these characteristic parameters the obtained cracking time is accurate and agrees well with the results of traditional strain method.The new criterion is more intuitive and easier for field uses.Thus this work provides a theoretical and technical support to application of acoustic emission to concrete fracturing tests.
出处
《水力发电学报》
EI
CSCD
北大核心
2011年第6期16-19,29,共5页
Journal of Hydroelectric Engineering
基金
水利部前期项目<地震对大坝灾变机理与对策研究>(S409001)
国家科技支撑计划课题<震损水库及堰塞湖风险评估与处置关键技术研究>(2009BAK56B04)资助
