Dynamic Response Of Asphalt Pavement Under Vehicle-Road Interaction Based On Discrete Element Method

The mechanical response of each structural layer of the pavement is an important indicator of the pavement design,and it is also the basic data for evaluating the road performance of the pavement and for in-depth study of the reasons for the damage of the pavement structure.At present,the pavement response is mainly studied through on-site monitoring and numerical simulation.Compared with on-site monitoring,numerical simulation does not require too much manpower and material resources,and has the advantages of high efficiency and repeatability.However,it is important for the mechanics of asphalt pavement under vehicle loading.When responding to numerical simulation,it is necessary to consider the impact of the interaction between the vehicle and the road surface.The size and position of the vehicle load will change with time,which has strong randomness.In addition,asphalt mixture is a discontinuous anisotropic material.The response under the action of external force is more complicated,and the usual continuous homogeneous theoretical method is difficult to accurately simulate the characteristics of asphalt mixture.Therefore,this paper builds an asphalt mixture pavement model based on the discrete element method and applies vehicle load to the model.To obtain the macro and mesoscopic response of the road surface under vehicle load,the main research work of the thesis is as follows:(1)Aiming at the limitation of PFC basic particle unit construction,the method of combining Matlab and PFC is used to model irregular particles,and construct irregular aggregate convex polyhedral template library.(2)Based on the discrete element uniaxial compression test,analyze the sensitivity relationship between the meso-parameters in the parallel bonding contact constitutive model and the macroscopic characteristics of the material,and calibrate the meso-parameters of the materials of each layer of the pavement to construct a true gradation and reflect the aggregate Irregularly shaped three-dimensional discrete element asphalt pavement model.(3)Two static loads of vehicle static load and vibration load are applied to the road surface,and the particle cloud image and macroscopic response of the road surface are extracted during the static load of the vehicle,and the force distribution and change trend of the road structure under the static load of the vehicle are analyzed.(4)The moving load under vehicle road interaction is applied to the pavement,and the macroscopic and microscopic responses of the pavement under vehicle road interaction are extracted.The responses of coarse aggregate and fine aggregate are compared and analyzed.In addition,the influence of vehicle speed on the pavement response is analyzed.These studies provide the basis for the further study of pavement damage under vehicle road interaction.