含反射裂缝的半刚性基层沥青路面断裂分析-结构工程专业论文.docxVIP

华中科技 大学硕士 学 华 中 科 技 大 学 硕 士 学 位 论 文 II II Abstract At present, reflective cracking which seriously affect pavement fatigue life and driving safety is widely existed in our country’s highway and become into a hard problem to deal with. Research on initiation mechanism and propagation behavior of cracks in asphalt pavements is necessary for a sound evaluation of mechanistic behavior of pavements. It is a great help to us to understand the state of the stress field and crack expanding path, to improve understanding of the mechanism of pavement damage and premature failure, and to provide guidance for pavement engineers in designing and maintaining asphalt pavements. It also has especially important significance to boosting highway traffic infrastructural facilities health development of our country. In this dissertation, after depicting the singularity of stress field at the top of crack, the finite element method to calculate stress intensity factor of plain fracture problems is founded. And formation of the two singularity elements, six knot triangles element and eight knot quadrilaterals element has been proved. Singularity field of the crack tip, the fracture criterion of mixed-mode crack has been also discussed. According to fracture mechanics principle, two-dimensional ANSYS finite element method procedure, the structural response of pavement suffering reflective analyzed in terms of traffic load. As for traffic load analyzed, symmetrical load and asymmetric load, in each of them, crack shear stress and stress intensity factor were calculated, also the effect of structural parameters were analyzed. And also dynamic viscolinear mechanics and fracture mechanics theory, were used for numerical simulation of asphalt concrete pavement under single period vehicle loading by FEM. The discipline of dynamic stress intensity factor(DSIF) was obtained when the temperature field, loading period of the vehicle were changing. The results showed that the maxi-mum DSIF decreased