Dynamic Coupled Analysis Of Satruated Asphalt Pavement And Design Method Of Pavement Drainage System Based On Unsaturated Flow Theory

In high-rainfall area, the water-induced damage is the main disease in asphalt pavement. The infiltrated water from pavement surface, as well as the coupled interaction between pavement structure and moving traffic loads, is one of the key casues which give the contribution to the water-induced damage. Adoping a reasonbable and effecitive waterproof and daiange system is a significant mearsurement to reduce water-induce damage. Therefore, based on the Boit dynamics consolidation theory and the assumption of linear elastic material, the models which take the retention water in pavement structure into consideration were established. Through the methods of numerical transform and programming, the semi-analytical and numerical solutions of muti-phyical fields in pavement (e.g., stress field, seepage field, displacement field and acceleration field) were obtained in order to illustrate the mechanism of water-induced damage as well as to offer the theoretical foundation to the design method of waterproof and drainage. In addition, based on saturated and unsaturated flow theory, the drainage models, including steady state and transient flow models for evaluating drainage-layer drainage system of pavement, were established, which extended and improved the design method of inner drainage system in pavement as well as the evaluation system of pavement thereby offering the theoretical foundation to a design method of driange system which is based on unsaturated flow theory. By systemic theory derivation and numerical calculation, we obtained the innovative achievements as follows:(1) Based on Biot dynamic consolidation theory, the physical model of three-layer system of pavement including surface course, base course and subgrade was esatablised and the hydro-mechenical coupled governing equations of pavement subjected to moving traffic load were obtained; Meanwhile, based on Biot dynamic consolidation theory, the physical model of four-layer system of pavement including surface course, drainage layer, semi-rigid base course and subgrade was esatablised and the hydro-mechenical coupled governing equations of pavement subjected to moving traffic load were obtained. Furter, the corresponding solutions of the governing equations were obtained respectively.(2) A model representing the water exchange between surface course and drainage layer was established and a fomular to calculate the water quantity infiltrating into the pavement were obtained, which take into consideration the crack properties and the damage level of crack map distributed in pavement surface.(3) By considering the capillary effect on the water flow in drainage layer, a model to quantify the capillarity in driange layer was established, which is based on the steady state Boussinesq equation integrating the Gardner water retention curve. Further, the semi-analytical solution was obtained for predicting the water-table height under the condition of steady state flow(4) Based on transient Boussinesq equation integrating Gardner water retention curve, a transient drainage model for drainage-layer drainage system was established. Further, the transient analytical solution of governing equation was obtained and the explicit expression was derived which describes the relationship between drainage and time to quantify the drainage capacity of drainage layer on the basis of the transient solution.