The Numerical Simulation Analysis Of Asphalt Pavement Moisture Damage Fatigue Failure Process

The instantaneous super pore water pressure produced by the pore water of the inner structure of asphalt pavement, under the action of the high speed wheel load, is an important reason that results in water damage of the pavement. Additional stess produced by pore water pressure, make the pore enlargement, make pore become large and form the macroscopic crack which expands gradually, accelerating the breakage of the asphalt pavment.Aiming at the problem of water breakage of the asphalt pavement, this paper systematically introduces the domestic and international research for doing this works, simultaneity analyses the reason and processes of water damage of the road surface in detail, and puts forward a series of measures to prevent it. Owing to that the domestic and international have done little about synthetical analysis of super pore water pressure and fatigue damage of the subground and pavement layer flexible system under the action of traffic load. So this paper first puts forward the mechanics analysis model of water damage of the asphalt pavement, which is based on Biot concretion seepage theory and isotropy linear elastic damage theory and fatigue damage theory, use axis symmetry finite element method to solve this problem and produce a finite element program to simulate it numercally. The paper emphatically analyzes the influence which pore water pressure take to asphalt pavement under stress and the fatigue damage process under the existing of the pore water and under the action of traffic load.Calculation results indicate, pore water pressure in the inner asphalt pavement nearly has close relative to permeate coefficient of surface, thickness of surface, material parameter and wheel speed etc. When the pore of pavement is full of water, under the action of load, the existence of the pore water can cause that stress concentration pricks up. Under the iterative function of load, it causes the pavement fatigue cracking, and accelerates the appearing of breakage of pavement.