基于多相复合电导特性的混凝土坝渗漏诊断研究

The water leakage of concrete dam will raise uplift pressure, increase the frost heave and freeze-thaw damage, endanger the safe operation of the dam. How to accurately ascertain the spatial distribution and morphology of the water leakage is very important. The following studies will be carried out in this proposal: Firstly, studying on the "solid - water - air" multiphase composite conductivity characteristics of concrete dam in the service environment, the effective conductivity model of hydraulic concrete composite medium will be built, and the mathematical relation between the effective conductivity and water leakage channel characterization parameters (air ratio, water content) will be determined at the same time. Secondly, in order to obtain the high quality observing data of apparent conductivity, the apparent conductivity observing method will be researched, which include seeking suitable electrode arrangement system, electrode distance and survey line layout for observing the apparent conductivity of concrete dam. Then, for the sake of realizing 3-d inversion of effective conductivity from apparent conductivity data, the 3-d inversing method of effective conductivity basing the conductivity theory limitation as the constraint conditions will be researched, and then the spatial distribution of air and water in concrete dam will be obtained on the basis of the effective conductivity model. Finally, for achieving accurate detection of concrete dam seepage, the intelligent recognition method based on the porosity and moisture distribution characteristics of hydraulic concrete seepage zone shape and position will be researched. This research can develop the nondestructive prospecting theory of hydraulic concrete structure, which has an important scientific theory value and engineering practical significance to the reservoir dam troubleshooting and repairing in China.

混凝土坝体渗漏会抬高扬压力、加剧冻胀和冻融破坏，影响大坝的寿命和运行安全。准确探明坝体渗漏路径的形态和分布至关重要。.本项目通过研究服役环境下水工混凝土的“固-水-气”复合电导特性，建立混凝土坝有效电导率与渗漏路径表征参数（空气比、含水量）的数学关系；通过现场试验，研究适合混凝土坝渗漏电法诊断的检测方案，寻求合理的电极方式、电极距和测线布置，据此得到高分辨率的视电导率数据；基于电法检测的视电导率数据，以坝体内部结构为先验信息、以多相复合介质电导率的理论界限为约束条件，研究由视电导率到有效电导率的三维反演方法，进而依据有效电导率反演结果和有效电导率模型，可反算得到空气比、含水量分布；通过考虑渗漏路径周围混凝土的空气比和含水量分布特征，借助模式识别和聚类分析，实现混凝土坝渗漏路径形态和空间分布的智能辨识。项目研究可发展电法无损检测理论，为水工混凝土结构的裂缝、缺陷和渗漏诊断提供理论和技术支持。

混凝土坝体渗漏会抬高扬压力、加剧冻胀和冻融破坏，影响大坝的寿命和运行安全。准确探明坝体渗漏路径的形态和分布至关重要。.本项目基于多相复合介质电导理论，推导了混凝土坝有效电导率与渗漏路径表征参数（空气比、含水量）的数学关系，建立了水工混凝土“固-水-气”复合介质的有效电导率模型。研究了四电极装置的测试范围，制定了水工混凝土电导率的四电极测试实验方案。通过系列室内实验，分别研究了胶凝材料、水泥砂浆材料、水工混凝土材料的电导率，得到水工混凝土固相材料在复合电导率模型的构成因子，进一步通过实验研究了水工混凝土“固-水-气”三相复合电导率的构成因子，确立了水工混凝土多相复合介质有效电导率模型的主要参数。通过物理模型试验和数值试验，研究了电极排列对横纵分辨率的影响、低(高)阻异常体尺寸及相对位置对识别分辨率的影响，进行了测线布置及不同电极排列的测试，得到适合混凝土坝渗漏电法诊断的检测方案。基于电法检测的视电导率数据，以坝体内部结构为先验信息、以多相复合介质电导率的理论界限为约束条件，研究了由视电导率到有效电导率的最小二乘、神经网络反演方法，进而依据有效电导率反演结果和有效电导率模型，可反算得到空气比、含水量分布，通过考虑渗漏路径周围混凝土的空气比和含水量分布特征，获得混凝土坝渗漏路径形态和空间分布。项目研究成果发展了电法无损检测理论，为水工混凝土结构的裂缝、缺陷和渗漏诊断提供理论和技术支持。

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