渗透溶蚀混凝土坝力学性能空间变异机理及影响研究

The completely random field based structural numerical analysis methods cannot reflect the natural spatial mechanical property distribution and the real structural behavior of obsolete and defective dams. Therefore, the research on leakage dissolution, which is a typical degradation scenario of concrete dams in China, has great significance both in theory and application. Related research aspects include leakage dissolution-affected spatial mechanical property variability mechanisms and its influences on structural behavior. In this research, first the multi-scale (cement paste, mortar and concrete) physical models under coupled internal and external factors will be carried out to simulate the leakage dissolution process and determine the mechanical property degradation evolution of dam concrete, and then the elasto-plastic damage constitutive model with internal parameters for leakage dissolution-affected concrete can be established. Based on these, the large-scale concrete dam models within micro- or macro-scopic defects will be prepared to investigate the spatial variability mechanisms of material mechanical property due to leakage dissolution. After obtained the dimension effect between the large-scale experimental model and the real dam, both the spatial dissolution expansion regularity and the spatial correlation of mechanical property of leakage dissolution-affected dams can be deduced. Taken these as a basis, the limited information based conditional numerical random field simulation method for characterizing the spatial mechanical property distribution of leakage dissolution-affected dams can be proposed with the help of the conditional random theory. Finally, the dynamic finite element method based on the random finite element method, the established elasto-plastic damage constitutive model, and the proposed conditional random field method can be developed to explore the potential effects of spatial variability of concrete mechanical properties on structural integrity and safety for leakage dissolution-affected dams. This research can provide solid theoretical supports and effective approaches for spatial mechanical property distribution identification and structural behavior analysis of obsolete and defective dams.

基于完全随机场的结构数值分析方法不能反映老坝病坝的真实面貌和结构性态。为此，针对渗透溶蚀这一我国混凝土坝常见病害问题，开展坝体力学性能空间变异机理探索、模拟和影响分析研究具有较高的理论意义和应用前景。本项目基于水泥浆体、砂浆和混凝土的多尺度模型试验，阐释内外多因素耦合溶蚀下各尺度材料的力学性能衰变规律，建立溶蚀混凝土弹塑性损伤本构模型；据此设计含宏、细观缺陷的大比尺混凝土坝模型溶蚀和多尺度力学性能试验，探索模型力学性能空间变异机理，并通过尺寸效应分析，推导渗透溶蚀混凝土坝力学性能的空间相关关系和损伤分布规律；进而借助随机场理论，研究基于有限信息的空间变异的坝体力学性能参数条件随机场模拟方法，提出基于弹塑性损伤模型的结构随机有限元动力分析方法，最终揭示渗透溶蚀对混凝土坝结构动力性态的影响。本项目取得的成果可为老坝病坝真实面貌识别和性态分析提供科学依据和有效的方法途径。

渗漏溶蚀是我国混凝土坝的常见病害问题，其时空演变机理与影响的基础和应用研究具有实际意义。应用多尺度数值模拟方法，探索了内外多因素下混凝土溶蚀孕育诱发演化机制和性能演变规律，建立了溶蚀混凝土力学性能衰减的弹塑性损伤模型。现场研究了多因素下含宏、细观缺陷混凝土坝的空间多尺度溶蚀演化和性能演变机理，分析了渗漏溶蚀下坝体局部、整体性能的相关关系。借助随机场理论提出了基于多源实测信息的坝体性能参数随机场模拟方法。在此基础上，发展了随机有限元分析方法，提出了渗漏溶蚀下混凝土坝性态分析方法。形成了基于多源信息的、考虑坝体性能时空变异的、突出灾变机理的渗漏溶蚀下混凝土坝性态分析理论和方法体系，深化了对渗漏溶蚀影响和致灾机理的认识。项目取得成果可为混凝土坝的长效安全运行提供理论支撑和科学依据。