Mechanical Analysis Of Asphalt Pavement And Its Parameter Inversion Research Based On Nonlinearity

Asphalt pavement's mechanical response and its inverse problem have become one of the important topics in the field of road engineering both at home and abroad. Nowadays, in the design of asphalt pavement structure, the current specification still regards the unbound aggregate base and subgrade's resilience modulus as constant; the inversion researches of pavement structure's parameters and mechanical response are still mainly based on linear elastic theory, however, this isn't in line with the real stress distribution in asphalt pavement structure. Therefore, it is necessary to research the nonlinear mechanical behavior of asphalt pavement and to inversely calculate and predict the asphalt pavement structure's parameters and mechanical response. This will have very important practical significance on the improvement of asphalt pavements' design theory system and the progress of asphalt road surface's design level. The main contents of this paper are as follows:(1) With the aid of finite element software called ILLI–PAVE, There were three kinds of pavement structure compared with the mechanical behaviors in the situation of overloading. The three kinds of structure, respectively, were that the first one considered neither unbound aggregate's nonlinear nor subgrade's nonlinear, that the second one only considered unbound aggregate's nonlinear, and that the last one only considered subgrade's nonlinear. This practice would highlight the necessity of considering both unbound aggregate's nonlinear and subgrade's nonlinear, and provided the basis of estimating asphalt surface's service life based on the nonlinear mechanical behavior.(2) Based on considering both unbound aggregate's nonlinear and subgrade's nonlinear, the asphalt pavement structure's parameters and mechanical response were calculated in the condition of the standard axle load, different asphalt layer thickness, different asphalt layer modulus, different base layer thickness, different base layer' modulus parameters and different subgrade' modulus parameters. Then the prediction model of GEP between the pavement mechanical response parameters and the pavement structure parameters were established to predict the deflection of pavement surface, asphalt tensile strain, the compressive strain and the vertical deviator stress of subgrade.(3) Based on considering both unbound aggregate's nonlinear and subgrade's nonlinear, the deflection basin of pavement surface were calculated in the condition of the standard axle load, different asphalt layer thickness, different asphalt layer modulus, different base layer thickness, different base layer' modulus parameters and different subgrade' modulus parameters. Then the inversion model of GEP between the pavement mechanical response parameters, the pavement structure parameters and the deflection basin of pavement surface were established to inverse asphalt layer modulus, modulus parameters of base layer, modulus parameters of subgrade, asphalt tensile strain, the compressive strain and the vertical deviator stress of subgrade.