瑞利波法检测混凝土表面裂缝深度的影响因素研究  

Study on influencing factors of detecting surface crack depth with Rayleigh wave detection method

作　　者：罗广衡 潘坚文[1] 王进廷[1] LUO Guangheng;PAN Jianwen;WANG Jinting(State Key Laboratory of Hydroscience and Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学水沙科学与水利水电工程国家重点实验室,北京100084

出　　处：《水利水电技术（中英文）》2021年第9期165-171,共7页Water Resources and Hydropower Engineering

基　　金：国家重点研发计划项目(2018YFC0406705);国家自然科学基金项目(52022047,51725901,51639006)。

摘　　要：基于瑞利波检测具有对裂缝敏感、操作简单、可单侧检测等优点,采用有限元数值模拟试验方法,进行了瑞利波检测混凝土表面裂缝深度的定量研究。在频谱比和频率的变化曲线中,给出截止频率与瑞利波波长之间的关系,建立了不同裂缝深度与截止频率之间的关系,并提出合适的激励频率范围。通过分析近场瑞利波的衍射效应,总结了不同深度的裂缝对相同频率瑞利波的放大规律,从而确定出由裂缝引起的振荡区间,提出了合适的检测道距以减弱衍射效应。通过讨论SASW法相位谱和频散曲线中由于裂缝的存在而产生的“突变点”与截止频率之间的关联,比较分析了截止频率法和SASW方法对裂缝的识别结果,根据频率的变化阐述两种方法内在的联系,为实际工程中混凝土表面裂缝检测提供理论依据。Based on the merits of Rayleigh wave detection method,i.e.sensitive to crack,easy to be operated,unilateral detection,etc.,a quantitative study on detecting the depth of concrete surface crack by means of Rayleigh wave detection is carried out herein through the relevant finite element numerical method.In the spectrum ratio and frequency variation curve,the relationship between cutoff frequency and Rayleigh wave length is given out,and then the relationships among different crack depths and the cutoff frequencies are established,while suitable excitation frequency ranges are put forward as well.Through the analysis on the diffraction effect of near-field Rayleigh wave,the amplification laws of Rayleigh waves with the same frequencies for the cracks with different depths are analyzed,and then the oscillation intervals caused by cracks are determined,thus suitable detection track-distances are put forward for weakening the diffraction effect.Moreover,the correlation between the mutation point caused due to the existence of crack and the cutoff frequency in the phase spectrum and dispersion curve of SASW method is discussed,while the crack identification results from both the cutoff frequency method and SASW method are comparatively analyzed.Furthermore,the internal relations of both the methods are expounded according to the relevant frequency changes,and then a theoretical basis is provided for the concrete surface crack detection in the actual construction project concerned.

关 键 词：混凝土 裂缝 瑞利波 截止频率 衍射效应 SASW 

分 类 号：TV698.15[水利工程—水利水电工程]