Simulation Method And Program Implementation Of Pavement Dynamic Response Based On The Spectral Element Method

In highway engineering,pavement deflection detection is an important way of highway maintenance.There are many methods for highway detection.Among them,the method of nondestructive testing is more and more popular.The main nondestructive testing instrument is the falling weight deflectometer,and the impact load on the circular surface generated by it can well simulate the driving load.The response of impact load on pavement can be converted into data information by sensors and computers.By analyzing these data,the pavement structure can be preliminarily evaluated,thus providing a reliable basis for pavement maintenance.However,the results of nondestructive testing experiment need to be compared with the results of theoretical calculation,through which the reliability evaluation of pavement can be more accurate.This paper takes the road surface detection by the falling weight deflectometer as the engineering background and the calculation of the dynamic response of the road surface as the target.The research contents are as follows:(1)This paper introduces a set of meaningful pavement dynamic response calculation theory system from spectral element method and mathematical calculation method.In order to consider the viscoelastic effects of pavement,the constitutive relations of three rheological models in frequency domain are derived,which are the Kelvin model,the Kelvin modified model and the Burgers model.According to the theoretical calculation process,a set of pavement dynamic response calculation program code is written by C++.(2)In order to verify the correctness of the program for dynamic response calculation of pavement,this paper takes the multi-layer model of homogeneous isotropic linear elastic materials as an example,compares the results calculated by the finite element software ABAQUS with the results calculated by the program,and verifies the correctness of the program on the pavement dynamic response calculation.In the process of verification,it is concluded that damping has a great influence on linear elasticity.(3)In highway engineering,high temperature and other factors have great influence on road surface materials.Materials are often viscoelastic.In this paper,the linear elastic multilayer model,the viscoelastic multilayer model and the multilayer model with the combination of linear elastic layer and viscoelastic layer are studied.For the linear elastic multilayer model,the research shows that the layer thickness and the layer modulus have great influence on the pavement deflection.For the viscoelastic multilayer model,the calculation results of the three rheological models are compared.At the same time,compared with linear elasticity,viscoelasticity is less sensitive to damping.In terms of size and material parameters,the influence of layer thickness and Poisson ratio on pavement deflection is greater.For the multilayer model with the combination of linear elastic layer and viscoelastic layer,the research shows that the pavement deflection increases with the increase of viscoelastic layer.Therefore,viscoelasticity has a profound effect on pavement deflection.