The Research On Calculation And Treated Technology Of Interface About Large Thickness Of Semi-rigid Base Asphalt Pavement

Large thickness of semi-rigid base is composed of stabilized material in this layer and it is often up to 35cm.This category of structure has many advantages, for example, it can spread load stress and have superiority economical. Due to increase the thickness of semi-rigid base, its construction has been divided into two layers-upper base and under base-to prove the degree of compaction. The problem about coupling of interface between upper base and the under one comes out. Meanwhile, the technology of base construction is so diversable that it is hard to evaluate the bulk strength of pavement. Therefore, it is necessary to have researches on the design method about large thickness of semi-rigid base asphalt pavement.This paper discusses the different interface characteristic by lots of experiments carried out in laboratory and establishes the model of interface between upper and under base. Base on the 3D nonlinear Finite Element Model, pavement deflection and tension stress on the bottom of base can be calculated by the Finite Element software.The result shows that pavement deflection and tension stress are closely relative to the base thickness, modulus and interface contact status. Compared with their interchange regulation and get the formula of calculating pavement deflection and tension stress on the bottom of base under two ideal conditions—free separation or fully contaction, Furthermore, induct two kinds of calculating coefficient and finally regress the formula which can be used to calculate the surface deflection and tension stress on the base courses bottom under any interface contact conditions between upper and under base.At last, for the sake of solving the bad contact condition in construction, test the interface coupling strength by two aspect: the one is interval time between the construction of upper base and the under one; another one is preset period. Quantifying the grout, which is to enhance the interface coupling, and definite the best dosage and water cement ratio of grout.