Study On The Dynamic Inverse-analysis Of Flexible Pavement Layer Modulus

There have been many achievements on pavements structure performance evaluation by using the data measured with FWD since FWD was used in pavement examination system in the end of 1970s in China. Back-calculate the modulus of pavement structure using the field measured deflection bowl data of FWD has been a hot research point now, and there have been many achievements. But most back-calculation methods used in practical engineering are based on simulate static model, in which the load is static which is different of the actual condition, and in this kind of method only every measured point's maximum deflection is used, too much information with FWD is unused. Other more, this kind of method ignores the impact of inertia force and damp, and considering the materials of pavement are very sensitive to dynamic factor, so some error is unavoidable.Considering that both the actual load on pavement and the load of FWD are all dynamic, in this article, dynamic response of pavement system was solved using finite element method and system identification of pavement layer parameters was achieved by iterative method which is based on sensitivity analysis depending on the dynamical analysis theory. Then, a program was written to realize the dynamic inverse-analysis of pavement layer modulus and compared with other method in practice so as to prove its usability and the correction of method. At last, we introduced its application and value in the evaluation of pavement system performance.In the study, we adopt dynamic analysis method and proceed pseudo-dynamic inverse-analysis, so that we can take advantage of FWD's abundant time-history information more sufficiently and simulate actual state of pavement system better. So the method has some engineering value.