砼桥板水平锈胀裂缝波动检测的理论与试验研究

A new method for detection of delamination in concrete bridge decks with stress waves is developed to meet the demand of quantitative inspection of bridge defects. The ultrasonic shear-horizontal (SH) waves are employed for the new method to overcome the challenges of invisible delamination within the decks and the unsatisfactory accuracy with current methods. The SH waves have two advantages: their dispersion characteristics are very sensitive to defect types and the wave reflection does not cause mode conversion. Based on these two advantages, the proposed method develops a criterion distinguishing delamination through the dispersion analysis and an approach estimating the position and size of delamination based on reflected waves. Wave equations are first established to study ultrasonic SH waves propagating in deteriorated concrete bridge decks, and then the dispersion function and energy transfer matrix of SH waves in concrete bridge decks are derived to build wave theories for detection of delamination with stress waves. The criterion for identifying delamination is proposed based on the analysis of effect of delamination on the dispersion characteristics and the inversion results. The approach for estimation of the location and size of delamination is developed based on the travel time calculation of SH waves in layered concrete bridge decks and the improved synthetic aperture focusing technique. Finally, the new method is established with the combination of the criterion and the approach, and the corresponding data analysis program is developed for accurately and quickly detect delamination in reinforced concrete bridge decks. The research outcomes of this study will provide useful theories and techniques for quality inspection of medium and small span reinforced concrete bridges, and promote the development of bridge maintenance towards quantitative inspection.

面向桥梁病害定量化检测的需求，发展砼桥板水平锈胀裂缝波动检测方法。针对铺装层覆盖下行车道板内水平锈胀裂缝的隐蔽性及精确检测的挑战，提出基于超声水平剪切波（SH波）的波动检测方法。利用SH波的频散特性对缺陷类型敏感和反射后不会发生波形转换的优点，提出基于超声SH波的水平锈胀裂缝判别准则和裂缝位置与尺寸确定方法。建立超声SH波在损伤多层砼桥板中传播的波动方程，研究超声SH波在损伤多层砼桥板中的波动频散和反射理论；分析水平锈胀裂缝对SH波频散特性和频散曲线反演计算结果的影响规律，建立裂缝判别准则；研究SH波在多层砼桥板内的传播时间计算方法和合成孔径聚焦技术，提出裂缝位置和尺寸确定方法。最终形成水平锈胀裂缝波动检测方法，并开发波动数据分析软件，能精确且快速地检测到砼桥板内水平锈胀裂缝。研究成果为中小跨径钢筋混凝土桥梁的质量检测提供理论和技术支持，推动桥梁养护向定量化检测方向发展。

面向桥梁病害定量化检测的需求，发展基于水平剪切波的混凝土桥板无损检测方法。首先，提出了基于SH波频散特性的混凝土剪切波速计算方法；利用SH波的频散特性对缺陷类型敏感和反射后不会发生波形转换的优点，提出基于超声SH波的混凝土开口裂缝深度估计方法和隐蔽水平锈胀裂缝成像方法。建立超声SH波在损伤混凝土桥板中传播的波动方程，研究超声SH波在损伤混凝土中的衍射和反射理论；分析开口裂缝对SH波衍射特性和传播时间的影响规律，建立开口裂缝深度估计方法；研究SH波在多层混凝土桥板内的传播时间计算方法和合成孔径聚焦技术，提出裂缝位置和尺寸确定方法。最终形成基于水平剪切波的混凝土桥板质量无损检测方法，并开发波动数据分析软件，能精确且快速地检测到混凝土桥板内隐蔽缺损。研究成果为中小跨径钢筋混凝土桥梁的质量检测提供理论和技术支持，推动桥梁养护向定量化检测方向发展。研究成果发表第一作者/通讯作者SCI期刊论文7篇、申请发明专利5项、授权软件著作权3项、参编标准1部。