Dynamic Response Analysis Of Asphalt Pavement Considering Unevenness Based On The Tire-pavement Coupling System

The existing design principle of asphalt pavement structure,which is based on the flat pavement surface assumption,simplifies the vehicle load as a rectangular uniformly distributed static pressure and then completes the calculation of each stress index,ignoring the complex dynamic interaction behavior between the vehicle and the pavement on an uneven pavement surface which usually occours in practice.Therefore,in this thesis,the dynamic response of asphalt pavement structure under the coupling system of tire and road is studied with the unevenness of pavement surface being considered.The finite element models of tire and pavement structures with different roughness levels are established in ABAQUS software.By introducing the appropriate contact mechanism between the above two models,a coupling system of tire and road is achieved.Subsequently,considering the sensitivity of asphalt material to temperature,the high temperature field in summer is modelled in ABAQUS,and the dynamic characteristics of asphalt pavement under various working conditions are comprehensively studied.And then the axial load conversion formula in the current pavement design specification is revised and supplemented.The main work of this thesis is as follows:First of all,based on the study of tires and pavement structure modeling theory,the finite element coupling model of tire and road is established in the software of ABAQUS,with sine wave simulating uneven pavement surface.Through the numerical example of this tire-pavement coupled system,the impacts that the tire role position,speed,axle load,and the modulus play onto the dynamic response of asphalt pavement are comprehensively analysed.Meanwhile it is confirmed that the road of ups and downs greatly influences the dynamic response of the entire pavement structure,especially on the underside of pavement.Secondly,taking the Power Spectral Density（PSD）of pavement as the variable of road roughness,adopting the idea of harmonic superposition method,and by means of Fourier transformation,the simulation of road height of A-level and F-level roughness was completed in Matlab software.Importing it into ABAQUS,the pavement structure models with different roughness levels are generated.Based on this model,the influence of unevenness on the stress index of each layer in pavement structure is analyzed.And a new physical quantity,the roughness coefficient C₃,is introduced into the axial load conversion formula of asphalt pavement to describe this effect,and the formula in the existing specification is revised.Finally,the dynamic stress response of uneven pavement under high temperature field in summer is studied.The temperature field of high temperature in summer is simulated by FILM and DFLUX subroutines.The influencing factors of temperature field are analyzed.And the temperature field of continuous change of asphalt pavement structure layer is calculated.Under this high temperature field,the dynamic stress response of asphalt pavement with unevenness are demonstrated and analyzed at different time of the same day.The other new physical quantity,the temperature coefficient C₄,is introduced into the axial load conversion formula of asphalt pavement to describe this effect,and the formula in the existing specification is revised again.