Study Of Parameter Identification And Damage Diagnosis On Light Retaining Wall System

Retaining structure is an important part in geotechnical engineering, has theextremely important status. If the health diagnosis of retaining structure is conducted ina timely and effective, can evaluate the overall safety of retaining structure, which willavoid the people’s life and property and the infrastructure suffered huge losses.Therefore the health diagnosis of the retaining structure is the most major problem inthe health monitoring and safety assessment system of retaining structure, in order todetermine whether the retaining structure is damage, damage location, damage degreeand trends of damage. In this paper, the research of health diagnosis is carried out on thelight retaining wall, based on the project of “development of health diagnosis instrumentfor geotechnical retaining structure”(No.51027004) for the national natural sciencefoundation instruments basic research project and the program of “Mountainousgeotechnical engineering”(No.IRT1045) for the changjiang scholar and innovativeresearch team, the added parameters identification, identification method of dynamicsignature, damage identification method of artificial intelligence and global stabilityevaluation of retaining wall system was studied. In this dissertation, the main originalwork includes:①In order to study modal characteristics and dynamic response of retaining wallsystem, the three-dimensional numerical model is established using finite elementmethod. The characteristics of retaining wall system modal were studied by integralorthogonal polynomial method and eigensystem realization algorithm.The influence ofsoil damage or retaining wall damage is researched on the modal characteristics and theamplitude spectrum curve of retaining wall system.②The dynamic-detection model is established to the health diagnosis of cantileverretaining wall system. At the same time, the added parameters of the soil are discussedin detail. Based on modal parameter identification, optimization design by finiteelement is proposed to identify added parameters of the soil. The identification resultsof added parameter were evaluated, which is calculated by different combinatorialoptimization methods and the different objective function. And the influence of themodal characteristics and dynamic response are analyzed on added damping of soil.③The modal mean curvature difference (MMCD) and flexibility-difference meancurvature (FDMC) is proposed. By a numerical simulation of cantilever retaining wall, comparative analysis with frequency rate (RF), the variation rates (RD), Gaussiancurvature mode difference (MGCD), to verify the sensitivity and effectiveness of thenew damage index.④Overall damage identification method and partition damage identificationmethod was proposed based on improved multiple population genetic algorithm anddamage characteristic equation of retaining wall system. The method can identify thedamage location and damage degree of retaining wall system effectively. Theapplicability, recognition accuracy, computational efficiency and validity of the twomethods are discussed by a numerical simulation of cantilever retaining wall.⑤The real-time evaluation method of global stability was studied on retainingwall system. The global stability is divided into three grades: stable, basically stable andunstable. A new method was proposed based on modal test and parameter identification.The soil is equivalent to a set of springs, and the earth pressure is expressed as the sumof the static earth pressure and the increment of earth pressure. The increment of earthpressure is assumed to the coefficient of subgrade reaction by the wall displacement.Combined with common degeneration theory, the earth pressure distribution form isobtained by iterative calculation. By comparing the calculation results with thecoulomb’s earth pressure theory, static earth pressure and the experimental ones, thefeasibility of the proposed method is validated. To further determine the global stabilityof the retaining wall system.