考虑材料劣化空间变异性的混凝土坝结构性能退化正反分析方法

在役混凝土坝现状结构性能是评估大坝安全性的主要依据之一，而环境侵蚀作用下材料劣化是混凝土坝结构性能退化的重要原因。因此，系统开展材料劣化作用下混凝土坝结构性能退化的分析研究具有十分重要的意义。鉴于混凝土坝结构性能退化机制的复杂性和现阶段混凝土坝材料劣化空间变异性方面研究的不足，本项目充分利用物理试验、数值仿真和原位监测，研究冻融-渗透溶蚀作用下侵蚀影响因素的时空演变规律，构建混凝土坝材料劣化空间变异性的表征模型；建立冻融-渗透溶蚀作用下混凝土坝的环境损伤时变模型，提出考虑材料劣化空间变异性的混凝土坝结构性能退化正分析方法；基于原位时空监测信息，研究并建立旨在辨识、监控和诊断混凝土坝结构性能退化行为的反分析模型，进而从正反分析两个角度揭示材料劣化作用下混凝土坝结构性能的退化特征，为长期服役混凝土坝结构性态诊断提供技术支撑和科学依据。

The current structural performance is an important basis for evaluating the safety of concrete dam in service, and the deterioration of material property under environmental erosion is a main reason for the degradation of structural performance. Therefore, it is of great significance to study the degradation characteristics from the perspective of structural performance, especially considering the influence of the spatial variability of deterioration degree of aged concrete dam's material property. Making full use of test, numerical simulation and in-situ monitoring, degradation characteristics of concrete dam structural performance will be revealed by the analysis and back analysis methods in this project. The spatio-temporal evolution law of erosion factors of freeze-thaw cycles and leakage dissolution will be analyzed, and a spatial variability model will be proposed to characterize the uneven deteriorated dam material property. On this basis, environmental damage model of concrete dam will be established, and the spatial variability considered-numerical simulation method for concrete dam structure performance degradation under the coupling action of loads, freeze-thaw cycles and leakage dissolution will be proposed. Furthermore, to identify, monitor and diagnose the performance degradation behavior of concrete dam, back analysis will be conducted by proposing two kinds of mathematical model based on the in-situ monitoring information. Through this project, some new technical support and scientific basis will be provided for the long-term service state diagnosis of existing concrete dams.