Numerical Simulation Of Transverse Cracking Of Asphalt Pavement And Structural Optimization Research

Semi-rigid-base asphalt pavement has been widely used in Chinese highways for decades due to its high strength,good stability,strong anti-scour ability and low engineering cost.Its main disease type is transverse cracking.The occurrence of transverse cracking can be explained by the fact that the length of the road surface along the driving direction is much longer than the lateral dimension and can be considered to be infinitely long.The temperature contraction along the driving direction is constrained by the base layer,resulting in tensile stress along the longitudinal direction.At present,the prediction models for transverse cracking of asphalt pavement at home and abroad are mostly empirical models based on actual crack survey data,which cannot explain the mechanism of generation and expansion of transverse cracking.Based on the measured parameters of pavement materials and related research result,this paper studies the three types of transverse cracking by finite element method: the dry shrinkage and temperature shrinkage cracking appears in the base layer during the health period;the temperature fatigue cracking appears in the asphalt surface layer under the external cyclic temperature load;the reflection crack caused by the base layer cracking extending.Firstly,the calculation formula of semi-rigid base dry shrinkage stress based on continuous elastic constraint is deduced.The dry shrinkage cracking process of semi-rigid base layer is analyzed with the measured parameters.The ABAQUS finite element software is used to establish uniform temperature field and exponential temperature field of the base layer.The temperature shrinkage stress was analyzed,and the distribution law of dry shrinkage and temperature shrinkage stress was obtained.The sensitivity analysis of the base layer temperature shrinkage stress was carried out.secondly,the relevant literature is used to obtain the meteorological data of Jilin Province and the thermophysical parameters of the pavement material.The heat transfer process is analyzed by ABAQUS software and the temperature field of the asphalt pavement is solved.The variation of the temperature field of the pavement structure with depth and time is given.Then,based on the Miner criterion,the asphalt pavement damage model under cyclical variable temperature load is derived.The ABAQUS software is used to analyze the temperature stress and its variation law of the pavement structure under the cyclic temperature field.Combined with the fatigue test results of the predecessors,the damage model shows the development law of road surface damage with time.The orthogonal analysis method is used to analyze the influencing factors of temperature stress,and the recommended structural combination of asphalt pavement based on the minimum surface temperature stress is obtained.Finally,the finite element calculation model of pavement structure with cracks is established.The crack stress intensity factor in crack propagation process is calculated.The temperature fatigue life is estimated,and the influence of base layer and surface layer parameters on crack propagation is analyzed.