混凝土结构渗水的压电智能监测方法与传输机制研究

Due to the absence of stable and effective water seepage monitoring method for important concrete engineering structures, a novel practical and reliable method was put forward to monitor water seepage based on the Smart Piezoceramic Aggregates (SPA). Meanwhile, the propagation mechanism of wave in multiphase concrete materials was studied deeply. This project was carried out by means of theoretical analysis, experimental study and numerical simulation as follows: Firstly, the performance of SPA in water environment and various environmental temperatures are experimentally investigated for improving the applicability and stability in situ monitoring; Secondly, the relationship of water seepage depth and longitudinal velocity or amplitude of stress wave in concrete was studied. An empirical equation for quantificationally estimating water seepage in actual engineering is provided. Thirdly, the influence of raw material compositions of porous multiphase concrete on wave velocity and energy is discussed based on propagation theory of stress wave in multiphase medium material, considering the dissipation characteristics and micro-structures of concrete materials. Finally, a simulation studied was conducted to analyze the effects of water seepage distribution on stress wave transmission, based on the inversion of concrete material parameters and monitoring signals. This study is critically important for improving durability and construction safety of important engineering projects.

本课题将针对重要混凝土工程结构渗水现象缺乏稳定有效监测方法的问题，力图提出一种基于压电智能传感器，适用于工程实际、稳定可靠的混凝土结构渗水监测新方法，并对波在混凝土多相材料中的传输规律进行深入剖析。本课题将采用理论分析、实验验证和数值模拟相结合的方式在以下几个方面展开系统研究：首先，为了提高传感器在实际工程环境的适用性和稳定性，摸索压电智能骨料传感器自身在水环境与环境温度场中的传输特性；其次，研究不同渗水深度与波传输信号（幅值、波速）的对应规律，给出工程适用的定量渗水评价经验公式；再次，结合波在多相介质传输理论、混凝土耗散特性和混凝土材料微观结构的表征，深入探讨多孔多相混凝土材料组成对波速与能量影响的机理；最后，基于监测信号分析和混凝土材料参数的反演，仿真研究混凝土内部水分分布对响应信号传输的影响。该研究对于提高重要工程结构的耐久性和安全性具有重要的理论意义和应用价值。

混凝土内部水的迁移是大多数耐久性问题的核心，如何精确确定混凝土内部水分分布是混凝土结构健康监测领域的一大难题。因此，研发广泛适用于多种恶劣环境下混凝土结构的新型渗水监测方法成为必需。鉴于现行监测方法具有精度低、稳定性差、受环境干扰大、耐久性差和对设备要求高等缺陷，该项目对以下几方面展开了研究：1）重点仿真模拟研究了粗骨料的弹性模量、面积率以及骨料形状和放置角度对应力波传播的影响，揭示了应力波在非均匀介质混凝土中的传播规律；2）试验研究了工作环境变化（水、温度）对压电智能骨料传感器的影响机制，为基于压电智能骨料传感器监测系统的现场应用提供了补偿措施；3）开展了孔隙率对应力波传播的影响研究，数值仿真模拟了应力波在不同孔隙率试件模型中的传播；4）开发了一种基于压电智能骨料的主动监测系统，以应力波波速和幅值为主要参数实现混凝土内部渗水深度的有效监测；5）提出和验证了一种混凝土结构微裂缝损伤的监测方法，探讨了裂缝对应力波传播的影响规律；6）试验研究了轴向受压应力对应力波在混凝土中传播的影响，发现了应力波在混凝土中传播波速随着应力的发展呈现出良好线性规律的现象，为混凝土在弹性应力范围内的结构轴向应力监测提出了一种新途径。上述研究成果为压电传感器大规模工程应用提供理论与数据支撑，对于提高重要工程结构的耐久性和安全性具有重要的理论意义和应用价值。在该项目的资助下发表SCI检索论文22篇，主要研究成果发表在《Structural Health Monitoring》，《Measurement》，《Smart Materials and Structures》等国际权威期刊；申请国家发明专利3项，已授权发明专利1项；培养硕士研究生7名、博士生3名；获得日内瓦国际发明展银奖1项，省市科技进步一等奖2项，市自然科学二等奖1项。