The Back-calculation Of The Pavement Flexible Material's Nonlinear Model Parameters Based On The Bearing-Plate Test

The parameter back-calculation of the pavement layer's resilient elastic modulus and its nonlinear parameters in stress-strain relation to know the stress condition of the pavement is the key to evaluate the pavement bearing ability. The research in this respect has been going on for twenties years in the world, many programs have been applied in the practice, and now still a high point for researchers. Most back-calculation theories are based on the linear elastic layer system and quietude analysis method, which neglected the nonlinear peculiarity of the pavement material. Therefore, selecting nonlinear stress-strain model and back-calculating with its parameters is the certainty development direction. There are many methods based on the displacement basin test by FWD, such as: Artificial Neural Network, Genetic Algorithm, Simulating Annealing and so on, however, the nonlinear back-calculation method based on the bearing-plate test are seldom, and still now has no outcome on the sight.The main theorem of this paper is to, firstly, on the grounds of experience preliminarily estimate the parameter of the pavement nonlinear model, simulate the process with computer procedure, and check the result with the data collected in sit, then set the aim function and the superiority back-calculation method, if the function is not satisfied, it is to the method adjust the parameter and make the model impend the actuality, If the function is satisfied, it is to end the process, and record the stress, deformation, displacement and the parameter as the actual condition. Then, in accordance with the parameter, we can get the distribution of the pavement's modulus and stress, strain displacement.One of the difficult of the paper is the contraction of the simulate process, as a means, the writer introduce the amended nonlinear least squares method as the superiority back-calculation method which enhance the contraction speed a lot after ameliorate with the paper problem. At the same time, aiming for the large quantity calculation and the amiss cumulation problem, some means to improve the calculate precision and accelerate the calculate process are also introduced, which all proved to be very effectively.Finally, a practice example is analyzed, the analysis result manifest the paper's procedure is credibility, the calculate data can satisfied the practice requirement, and provide reference for the construction.