Research Of Dynamic Response And Modulus Backcalculated Of Asphalt Pavement Based On FWD Load

The dynamic response of the pavement structure is one of the important topicsfor highway engineering. Most of the current highway design theory and performanceevaluation methods are based on pavement structure under the static vehicle loads inChina. Compared with the actual situation, there are some differences. The design andanalysis theory are still not perfect. With the increasing popularization of fallingweight deflectometer, the road carrying capacity evaluation and the backanalysis ofpavement structure layers’ modulus based on the information of deflection basin, havebeen one of the critical technology of the pavement structure performance evaluation.Therefore, the research on asphalt pavement dynamic response and backcalculationunder the FWD load has the important significance for dynamic design and themanagement maintenance of pavement. The primary contents in this thesis are asfollows:(1) Referring to the common form of pavement structure in our country, thethree-dimensional finite element analysis models of asphalt pavement based onlayered elastic theory were established to study dynamic response of asphaltpavement. The results summarized the regularity of surface deflection basin, tensilestrains of asphalt layer bottom and compressive strain on top of subgrade soilsfollowed the structure layer parameters’ changes.(2) Considering the materials’ gradient characteristics of asphalt pavementsurface layer and subgrade soils, the gradient modulus pavement structure analysismodels under FWD load have been established. The research showed the comparativeanalyses of mechanical behavior and law of dynamic response with the high and lowtemperature field, the low-temperature aging and different subgrade gradient features.(3) The database concluding various structure layers’ modulus, deflection basinand the layer’s thickness was set up by the three-dimensional finite element dynamicanalysis models. Based on the theory of support vector machine, the inversion modelsof the asphalt pavement structure layers’ modulus were built. The correlationcoefficient and error of the backcalculation results were counted. And the sensibilitiesof pavement modulus due to the different structural layer parameters were alsodiscussed.