基于波动测量的装配式钢筋混凝土柱套筒灌浆缺陷检测方法及机理研究

The quality of grouted splice sleeve connections (GSSCs) affects the mechanical behavior of prefabricated concrete (PC) structures and it is critical to develop reliable approaches to detect grouting defects in GSSCs. In this proposal, a novel grouting defects detection approach for GSSCs is proposed using piezoelectric lead zirconate titanate (PZT) patches as actuators and sensors mounted on rebars of GSSCs and PC structures. Experimental studies on GSSCs and PC specimens connected with GSSCs with various degrees of grouting defects at different locations are carried out to validate the feasibility of the proposed approach. Then three-dimensional (3D) coupling models composed of PZT patches and GSSC, PZT patches and PC specimens connected with GSSCs are made, respectively, considering the piezoelectric effect of PZT patches and the coupling effect between PZT patches and GSSCs and PC specimens. Multi-field numerical simulations on the stress wave propagation and the time-history response of surface-mounted PZT sensors are carried out. Based on the analysis on the characteristics of the PZT sensor response, the mechanism of the proposed grouting defects approach is investigated and the major factors affecting the behavior of the proposed approach are identified. Considering the meso-scale structure of concrete, numerical concrete modeling technology is employed to establish the multi-scale coupling models composed of GSSCs and PC member connected with GSSCs to simulate the stress wave propagation. The effects of grouting defects and the meso-scale structure of concrete on the PZT sensor measurement are studied to determine the dominance of grouting defects on the PZT sensor measurement. Finally, in order to improve the multi-scale simulation efficiency when meso-scale structure of concrete and its randomness are considered, a meso-scale homogenization approach for multi-scale concrete is employed to improve the simulation efficiency for the stress propagation. This study aims at the development of efficient grouting defect detection approach for GSSCs and the investigation of the mechanism.

钢筋套筒连接质量是影响装配式钢筋混凝土结构力学性能的关键因素之一，研究有效的套筒灌浆缺陷检测方法迫在眉睫。本项目提出一种利用钢筋表面粘贴压电陶瓷片进行驱动和应力波测量的套筒灌浆缺陷主动检测新方法；通过对存在不同位置和程度灌浆缺陷的套筒、由单个和多个套筒灌浆连接的预制钢筋混凝土柱的系列试验研究，验证其可行性；考虑压电陶瓷片的正逆压电效应，分别建立其与套筒、预制钢筋混凝土柱构成的三维耦合系统模型，开展不同激励下应力波场及压电传感器动力响应数值模拟，分析应力波测量信号特征，探究灌浆缺陷检测机理及关键影响因素；考虑混凝土材料细观结构及随机性，结合数值混凝土建模技术，开展套筒连接预制钢筋混凝土柱多尺度耦合系统数值模拟，分析灌浆缺陷与混凝土细观结构随机性对应力波传播特性的影响并比较；为提高考虑混凝土细观结构时钢筋套筒连接及构件中应力波传播模拟的效率，运用多尺度均匀化方法建立钢筋套筒连接与雅典陶瓷片耦合系统的多尺度细观模型，开展应力波传播特性的模拟。本研究拟解决的关键科学问题是考虑混凝土的细观特性采用波动测量的灌浆缺陷检测的可行性及机理，解决我国推广装配式结构中亟待解决的缺陷检测方法问题。

本项目针对我国建筑工业化和大力发展装配式建筑的背景下钢筋混凝土装配式结构中灌浆链接套筒缺陷检测方法匮乏的问题，开展了基于波动测量的装配式钢筋混凝土柱套筒灌浆缺陷检测方法及机理研究。按照项目计划书拟定的研究工作的内容和目标，充分发挥压电陶瓷智能材料的驱动和传感功能，提出了基于压电陶瓷驱动与传感的预制混凝土柱套筒灌浆缺陷检测新方法。在研究钢-混凝土组合构件中基于表面波测量的界面缺陷检测方法的基础上，开展基于压电波动测量的套筒灌浆缺陷检测新方法研究，设计和制作具有不同尺寸模拟灌浆缺陷的套筒试件，分别在套筒连接钢筋表面和套筒壁布置压电陶瓷传感器和驱动器，探讨不同信号类型与频率对套筒灌浆缺陷的检测能力，研究了压电陶瓷片的最优布置方式。基于测量信号的小波包能量及所定义的损伤指标值，对预制混凝土柱套筒灌浆缺陷进行定量评估，验证所提出方法对独立套筒灌浆缺陷检测的有效性。开展基于压电阻抗测量的套筒灌浆缺陷检测实验与数值模拟研究，试验结果表明，带有灌浆缺陷的套筒试件的阻抗-频率曲线峰值频率会发生偏移，建立的缺陷评价指标值能很好地反映套筒内灌浆缺陷程度。开展基于压电陶瓷驱动与测量的预制柱套筒灌浆缺陷检测研究，设计和制作不同长度灌浆缺陷的套筒试件并将其埋入混凝土中，试验结果验证了基于压电陶瓷驱动与传感的预制混凝土柱套筒灌浆缺陷检测方法的有效性。考虑混凝土的细观结构，建立压电材料与结构的多物理场耦合多物理场细观有限元数值模型和细观均匀化模型，探究基于压电陶瓷的套筒灌浆缺陷检测机理。数值计算结果表明灌浆缺陷会导致压电传感器响应电压信号幅值的增大，数值模拟结果规律与试验一致。完成了预定研究工作，成果以高水平SCI国际期刊论文为代表的系列论文发表，并和本领域国外相关专家开展了实质性的合作与交流。