| The construction of hydraulic engineering involves a tremendous amount of earth-rock filling, such as filling of harbor land, earth-rock dam and earth-rock foundation.While the filling of earth-rock composite medium is a typical multiphase material whichis consist of soil particles, rock particles, pore among particles, air and water in pore,whose gradation changes greatly and moisture content is extremely heterogeneous.There has a great impact on engineering properties with particle size, rock types, rockcontent, moisture content and compaction degree. Because the resistivity of earth-rockmedium is closely related to its structural parameter, it has significant effect on healthdiagnosis with resistivity testing technique for each earth-rock filling in hydraulicengineering. The resistivity characteristics and theoretical model of soil media is basedon the quality evaluation of earth-rock filling with resistivity testing technique. Atpresent, for pure rock medium or soil medium, lots of researches on resistivitycharacteristics have been done at home and abroad, the corresponding theoreticalsystem is formed basically. It has a great important effect on resistivity characteristicswith earth-rock particles features, rock content, moisture content and compaction degree,because of the correlation on each factor, the conductivity of multiphase earth-rockcomposite medium becomes very complicated, the application of engineeringexploration and detection in each earth-rock filling with testing technique is impeded bythe little theoretical research on resistivity. For this reason, in this paper, the resistivitycharacteristics of multiphase soil-rock composite medium have been researthed in depthbased on national natural science foundation (No.50779081), science and technologyprogram of JiangXi province ministry of transportation (No.2010C0016). The majorresearch content is as follows:(1) Research on conductivity and resistivity structure model of rock and soil medium.The conductivity and resistivity theory of pure rock medium and soil medium issummarized, resistivity characteristics of typical rock and soil medium is analyzed, themajor affecting factors on resistivity characteristics of rock and soil medium are studied,which lays the groundwork for theoretical research on resistivity of multiphase earth-rock composite medium.(2) Definition and study of physical mechanical properties on earth-rock compositemedium.Based on the study of domestic and international soil classification system, theconcept and content of earth-rock composite medium is defined, it has been studiedwith experiment respectively through continuous gradation and discontinuous gradation,the engineering properties are analyzed, the affecting factors for physical properties ofearth-rock composite medium are researched such as particle diameter, particle content,density and moisture content.(3) Experimental research of resistivity characteristics on multiphase earth-rockcomposite medium.Large quantities of earth-rock composite medium samples are made with different water content, porosity, saturation and soil-rock ratio, whose resistivity characteristicsand indexes of physical mechanical parameters are measured under different physicalstate. The affecting law of resistivity characteristics is studied with structure parametersof multiphase earth-rock composite medium such as comprehensive moisture content,porosity and soil-rock ratio, which lays the groundwork for analyzing the theoreticalrelationship between structural parameters and resistivity characteristics of earth-rockcomposite medium.(4) Theoretical model research of resistivity characteristics on multiphase earth-rockcomposite medium.Based on the existing resistivity model of unsaturated pure soil medium and rockmedium, the macroscopic equivalent conductive model of multiphase earth-rockcomposite medium is established with experiment law, structure model of resistivitycharacteristics on multiphase earth-rock composite medium is deduced, the theoreticalrelationship between structural parameters and resistivity characteristics of earth-rockcomposite medium is obtained, the theoretical system of characteristics on multiphaseearth-rock composite medium is built primary. On this basis, the inversion method onfeature parameter of earth-rock composite medium with theoretical model of resistivityis proposed.(5) Applied research on resistivity theory of multiphase earth-rock compositemedium.For the characteristics of earth-rock filling in hydraulic engineering, two differenttypes earth-rock filling model are designed, seepage diagnosis and compaction qualityevaluation is done respectively by resistivity testing technique. Firstly, the earth-rockdams are designed with different seepage, the crack and seepage paths in dam isdetected by different arrangement and spacing of electrode, compare the differentinversion results to the actual seepage crack in model, then the seepage of earth-rockdam is diagnosed with inversion and related physical parameters. Secondly, thefoundation models of earth-rock filling are designed with different defects, the physicalparameters is inverted with resistivity imaging which are closely related to compactionquality on earth-rock foundation that is evaluated with the method.The main innovation point is as follows：(1) According to the influencing factors of the electricity risitivity of the multiphaseearth-rock composite medium, the experimental law of resistivity characteristics isstudied with structure parameters of multiphase earth-rock composite medium such ascomprehensive moisture content, porosity and soil-rock ratio by test of the electricityrisitivty.(2) Based on the existing resistivity model of unsaturated pure soil medium and rockmedium, the macroscopic equivalent conductive model of multiphase earth-rockcomposite medium is established with experiment law, structure model of resistivitycharacteristics on multiphase earth-rock composite medium is deduced, the theoreticalrelationship between structural parameters and resistivity characteristics of earth-rockcomposite medium is obtained, the theoretical system of characteristics on multiphaseearth-rock composite medium is built primary.(3) Based on the theoretical relationship between structural parameters and resistivity characteristics of earth-rock composite medium, the inversion method on featureparameter of earth-rock composite medium with theoretical model of resistivity isproposed. For the characteristics of earth-rock filling in hydraulic engineering, seepagediagnosis and compaction quality evaluation is done respectively by resistivity testingtechnique. |
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