冲击回波法识别孔道灌浆缺陷尺寸的研究  

Research on identification of grouting defect size based on impact-echo method

作　　者：杨海林 张宏祥[2] YANG Hailin;ZHANG Hongxiang(School of Civil Engineering,Tangshan Polytechnic College,Tangshan 063299,China;School of Civil Engineering,Northeast Forestry University,Harbin 150040,China)

机构地区：[1]唐山工业职业技术学院建筑工程学院,唐山063299 [2]东北林业大学土木工程学院,哈尔滨150040

出　　处：《建筑结构》2023年第10期97-104,共8页Building Structure

基　　金：唐山市科学技术研究与发展计划(第三批)项目(20150221C)。

摘　　要：针对建筑结构中后张法预应力孔道的灌浆缺陷,采用冲击回波法对灌浆缺陷的识别进行研究。采用ANSYS/LS-DYNA软件建立了5种不同灌浆情况的有限元模型,同时建立了3组现场试验模型,采用冲击回波法进行了检测,得到了不同灌浆情况模型的频谱响应。通过对比理论计算频率与现场实测频率,研究了缺陷程度、预应力孔道材料、缺陷横截面周长对厚度主频和关键频率的影响,分析了不同因素对检测结果产生的误差;根据缺陷横截面半周长与名义厚度比值和板厚偏移率的关系推导了计算缺陷横截面周长的公式。结果表明:越靠近厚度主频,缺陷和钢绞线响应关键频率计算值与实测值的误差越小,越远离厚度主频其误差越大;一般密度的钢筋和箍筋对检测结果无影响;计算与实测的关键频率均随缺陷程度的增大而降低,且与厚度主频的变化趋势一致;塑料孔道模型的厚度主频和关键频率较金属孔道普遍向低频漂移,但各关键频率的影响系数和厚度主频的影响系数保持一致,可以据此估算出缺陷程度;缺陷尺寸越大,检测构件厚度越小,误差越小。Aiming at the grouting defects of post tensioned prestressed duct in building structure,the impact-echo method was adopted to identify the grouting defects.ANSYS/LS-DYNA software was used to establish finite element models for five different grouting situations,field test models of 3 groups were established for impact-echo testing,the spectral responses of the models under different grouting conditions were obtained.By comparing the theoretical calculation frequency with the on-site measurement frequency,the effects of defect degree,prestressed duct material and defect cross-section circumference on the thickness frequency and characteristic frequency were studied,the error caused by different factors on the inspection results was analyzed.Based on the relationship between the ratio of the half circumference of the defect cross-section to the nominal thickness and the plate thickness deviation rate,the formula for calculating the defect crosssection circumference was derived.The results show that the closer to the thickness frequency,the smaller the error between the calculated value and the measured value of characteristic frequencies of the response to defects and steel strands,the farther to the thickness frequency,the error becomes larger.The general density of reinforcement and stirrup has no influence on the test results;The calculated and measured characteristic frequencies decrease with the increase of defect degree,and the variation trend is consistent with the thickness frequency.The thickness frequency and characteristic frequency of the plastic duct model generally drift to low frequency compared with the metal duct model.However,the influence coefficient of each characteristic frequencies are consistent with the thickness frequency,and the degree of defects can still be estimated.The larger the defect size is,the smaller the thickness is,the smaller the error is.

关 键 词：冲击回波法 预应力孔道 灌浆缺陷 有限元模拟 频谱响应 缺陷横截面周长 

分 类 号：TU378[建筑科学—结构工程]