Study And Application Of Evaluation Method On Compaction Quality In Land Fill Based On Electric And Elastic Wave Imaging

Port construction engineerings often involves widespread filled projects of landfield on the mountains and reservoir which has characteristics of fill height, steeperslopes and influenced by the range of water level. The stability of land fill is directlyaffected by the compaction quality of fill.But because of the size distribution of filler changed greatly and the moisturecontent of filler changed unevenly, the existing test method of compaction is limited to acertain degree. So how to detect the compaction of the earth-rock mixture foundationfast, economically and effectively is an urgent problem to solve in current high fillbuilding technology on port construction.Based on the characteristics, such as resistivity is very sensitive to moisture contentof earth-rock mixture, while wave velocity is very sensitive to density of earth-rockmixture, according to the analysis of wave propagation characteristic and resistivitycharacteristics of earth-rock mixture with the method of theoretical analysis,model test,field test and imaging analysis, the compaction index inversion model of land fill isbuilt. Then wave field imaging evaluation method of compaction quality on land fill isestablished with tomography technology, forward and inversion model and observationinvestigation whose feasibility and reliability is verified by model test and engineeringapplication. The main studying contents of this paper are as follows:(1) Theory and experiment research on wave propagation characteristic of earth-rock mixtureBased on the study of macroscopic wave propagation characteristics and equivalentelastic characteristics of earth-rock mixture in port land fill, the equivalent wavepropagation characteristic of earth-rock mixture is researched systematically, the P-wave and S-wave velocity theoretical formulas is raised. According to the theoryformulas, influence factors of wave propagation are studied deeply. The reliability oftheoretical analys is further verified with the experimental research of wave propagationcharacteristics on earth-rock mixture,(2) Theory and experiment research on the resistivity characteristics of earth-rockmixtureOn the basis of the previous resistivity structure model on unsaturated cohesivesoil, according to the comprehensive analysis of main influence factors on soil electricalresistivity, the electrical resistivity structure model of foundation with earth-rock mixture on port land fill is established,then theoretical formula of electrical resistivityis deduced and the affecting factors of electrical resistivity on this foundation isanalyzed in detail; Subsequently, electrical resistivity characteristics of earth-rockmixture is researched with experimental. Based on the result of electrical resistivity test,the main influence factors of this media are analyzed deeply with three aspectsseparately which are compaction times, water content and earth-rock ratio.(3) Inversion model research of compaction index on port land fillOn the basis of the theoretical formulas between S-wave velocities of port land fill,electrical resistivity and physical properties parameters of earth-rock mixture, usemoisture content as common physical properties parameters of close relationship amongthem, then the theoretical formula between wave electric field parameters and earth-rock mixture parameters is built. The theoretical formula is shown with function, themacro-parameters (wave parameters, electric field parameters) and other relevantphysical parameters are as arguments which are easy to test, and the important physicalparameters such as dry density are dependent variable which reflects the compactionquality on soil-rock mixtures. Use degree of compaction as the control index ofcompaction quality for port land fill, and combine the function relationship between thewave electric field parameters and earth-rock mixture parameters, theoretical formula ofcompaction degree for port land fill is established with wave electrical couplingcharacteristics. The theoretical formula is further simplified for application expedientlyin actual engineering.(4) Wave-electric field imaging evaluation methods study ofBased on the acoustic tomography theory and least squares orthogonaldecomposition algorithm principle, velocity tomography implementing technology israised with LSQR inversion algorithm. Based on the minimum structure inversionmethod, the electrical resistivity tomography technology is proposed with conjugategradient inversion method. On this basis, combine the characteristics of port land fill,wave electric field imaging method of compaction quality on port land fill is establishedby the method of direct current test and wave fluctuation testing, and the program, stepsand analysis software of the wave-electric field imaging evaluation methods ofcompaction quality on port land fill is given.(5) The experiment research on imaging evaluation methods of compaction qualityimaging for port land fillIn order to verify the reliability and accuracy of compaction quality imagingevaluation methods on port land fill, three different un-compaction types are produced respectively which are contain empty zone, heterogeneous body, without compactedzone. The imaging observation and treatment of model is done by electrical resistivityimaging technology and elastic wave technology. According to the test results ofelectrical resistivity method, the moisture content distribution picture of test model iscalculated with theoretical formula between physical properties parameters of earth-rock mixture and electrical resistivity; Based on the simplified theoretical formula withwave electrical coupling characteristics for degree of compaction on port land fill, waterratio and the elastic wave velocity as the physical parameters, the degree of compactiondistribution picture on test model is obtained, and the space distribution is also obtained,combine the form of test model defection, the adaptability and reliability of this methodin inversing compaction quality on port land fill is verified.(6) The imaging evaluation on wave-electric field of compaction quality for portland area fill in FuningThe earth-rock mixture filler of land fill in Yunnan Funing port is done a field testby the way of transient Rayleigh wave method and direct current electric method. thedistribution picture of electrical resistivity on earth-rock mixture filler is obtained withelectrical resistivity, the water content distribution characteristics is also calculated; thetest data of transient Rayleigh wave is processed with simplified stripping method, thenthe S-wave distribution picture of earth-rock mixture filler is obtained; the degree ofcompaction distribution picture for test zone is obtained by the simplified theoreticalformula which is based on wave electrical coupling characteristics for degree ofcompaction on port land fill, Finally, the degree of compaction for spatial distributioncharacteristics is obtained on land fill in Funing port, and the compaction quality forport land area fill in Funing is evaluated.