Study On Dynamic Behavior Of Asphalt Pavement Based On Three-dimensional Tire-road Mesoscopic Coupling Model

With the increase of traffic flow in China year by year,the damage phenomena such as cracks,ruts and overcrowding of asphalt bridge deck pavement appear prematurely during its service period,which will seriously affect the road performance of highway asphalt pavement and the driving comfort and safety of vehicles.As a multiphase composite,asphalt mixture is composed of a variety of different components,and the contact models between them are also different,with complex constitutive relations.Therefore,it is necessary to reveal the failure mechanism of asphalt pavement by studying the meso-mechanical behavior of asphalt pavement under traffic load,which has certain engineering guiding significance for highway design and maintenance.Based on the discrete element method,the asphalt mixture model is divided into three parts: coarse aggregate,fine aggregate,and void.Using Solidworks software to produce irregular coarse aggregate,making the model closer to actual working conditions;The Burgers constitutive model is used to characterize the viscoelastic properties of asphalt mortar.The macroscopic mechanical parameters of the Burgers model are obtained through asphalt creep tests,and the microscopic modeling parameters are obtained based on the conversion formula between macroscopic and microscopic parameters;A discrete element software program is used to randomly generate a mesoscopic model of asphalt mixture with the required gradation.Finally,relevant indoor rutting experiments are conducted to verify the effectiveness and correctness of the three-dimensional mesostructure model.Using the above verified asphalt pavement model,the rolling tire force is simplified as the equivalent load to load the pavement,and the time temperature equivalence principle is used to improve the calculation efficiency.The macro rut evolution and micro mechanical behavior of asphalt pavement under the influence of common factors are studied,and the generation and development process of rut is described from the perspective of the internal micro of asphalt mixture.The discrete element method is used to simplify the tire into three parts : hub,spoke and tread to express its model properties.Different contact models are given to each part,and a nonlinear discrete element tire model is established.The static stiffness loading and rolling loading simulation were carried out to verify the meso-mechanical behavior of the tire model under load,and the stress distribution and grounding imprint of the tire-road interaction were explored.Based on the pavement model and tire model verified above,a three-dimensional mesoscopic model of the coupling of tire and bridge deck asphalt pavement is constructed to explore the meso-mechanical response of asphalt bridge deck under the influence of rolling tires and reveal the damage mechanism of bridge deck.This study can provide a theoretical basis for the optimization design method of asphalt bridge deck structure,and provide technical support for its targeted maintenance.