Development And Application Of Pavement Modeling Program Based On Semi-Analytical Finite Element Method

Analyzing mechanical responses induced by traffic loads is a significant issue for pavement design and performance evaluation.Developing a three-dimensional finite element model in commercial FE software is an effective method used commonly,but the time-consuming disadvantage prevents it from many engineering applications.The semi-analytical finite element method(SAFEM),which substitutes meshing with the interpolations of Fourier series along the longitudinal dimension and transforms the original 3D modeling issue into a set of 2D problems,can significantly reduce the calculation time while ensuring the accuracy.This method has been applied in some simple analyses of pavement mechanical response,but for dynamic analysis,boundary condition setting,and some more complicated situations,in-depth research is still required.In views of the four basic load response analysis situations of static elasticity,static viscoelasticity,dynamic elasticity,and dynamic viscoelasticity,this article aims to improve further the semi-analytical finite element modeling method for road engineering and draw on the theory and MATLAB programming establish CP-SAFEM(cement pavement SAFEM)for load response analysis of cement pavement and SAPAVE(semi-analytical pavement)for load response analysis of flexible pavement.Firstly,combined with the SAFEM for static elastic analysis and the structural characteristics of cement pavement,the analysis program CP-SAFEM was developed.A series of comparative studies indicate that the calculation error between CP-SAFEM and the existing standards was less than 6%for both single-layer and double-layer pavements.Besides,the errors of all load responses between CP-SAFEM and the 3D model in ABAQUS were less than 5%,while the computation time of CPSAFEM was only that 1/6 that of ABAQUS.Further,the critical loading position was determined by the tensile stress calculated by this program.Secondly,the viscoelastic stress integration of SAFEM was derived,and a SAFEM model assembled with the viscoelastic constitutive model was developed.Based on the improved model,the analysis program SAPAVE was proposed for static viscoelastic analysis of flexible pavement.Next,the bending beam rheometer(BBR)test results of several asphalt binders were in comparison with the results predicted by this program.Both results were in agreement,which proved the validity of this program.Furthermore,utilize this program to analyze the static response of a typical flexible pavement,and compare the mechanical analysis with a 3D model in ABAQUS.Both investigations show that this program is an efficient approach for the viscoelastic analysis of pavement.Thirdly,referring to the dynamic analysis method of the 3D finite element model,the dynamic elastic analysis method of SAFEM is derived,and the corresponding analysis function of SAPAVE was completed accordingly.The improved modeling theory,which was upgraded mainly in the modified boundary conditions and parallel computation technology,was presented in detail.Furthermore,this program was utilized in a field pavement to analyze dynamic responses,which was compared with the field data monitored by sensors.The results of all studies indicate that the efficiency of SAPAVE is remarkable while guaranteeing adequate accuracy.This case also has some reference value about the program usage for road engineers.Finally,integrating those above the dynamic elastic and static viscoelastic analysis methods to derive the dynamic viscoelastic analysis method of SAFEM and the corresponding analysis function of SAPAVE was completed accordingly.Further,the accuracy and efficiency of this program were verified by comparing its analysis results of a typical flexible pavement with a 3D model in ABAQUS.Besides,the impact of vehicle speed on dynamic response was studied to examine the application ability of SAPAVE,and the analytical results of SAPAVE are generally consistent with the existing research conclusions.Overall,this study indicates that SAPAVE is an efficient and accurate tool for mechanical analysis of asphalt pavement.