半刚性基层沥青路面疲劳裂缝扩展与寿命预估研究

以疲劳断裂力学理论和材料试验为基础，对半刚性基层沥青路面裂缝的扩展行为进行系统研究，分析了裂缝尖端的应力强度因子变化规律和偏荷载作用下各影响因素对疲劳寿命的影响；结合路面结构初始状态的荷载响应，回归得到了路面的疲劳寿命预估方程。结果表明，路面疲劳主要是由偏荷载作用于横向裂缝导致，疲劳寿命随面层整体模量和轴载增长而递减，随基层模量、路基模量、中面层厚度、基层厚度增长和车速而递增，随下面层厚度的增长先减后增。回归得到的疲劳寿命预估方程考虑的影响因素更加全面，为我国路面结构设计和科研提供了理论支持和补充。

Research on fatigue crack propagation and fatigue life prediction of semi-rigid base asphalt pavement

Based on fatigue fracture mechanics and material test, the crack propagation behavior of semi-rigid asphalt pavement was systematically studied, and the variation law of the stress intensity factor at the crack tip and the influences of various influencing factors to the fatigue life under the off-axis load were studied; in combination with the load response of the initial state of pavement, the prediction formulation of the fatigue life of pavement was attained by regression. The results show that the fatigue of pavement is mainly caused due to the off-axis load acting on the transverse cracks, the fatigue life decreases with the growth of the overall modulus of surface course and the axle load, increase with the growth of the modulus of base course, the modulus of subgrade, the thickness of the middle surface course, the thickness of base course and vehicle speed, firstly decrease and then increase with the growth of the thickness of lower surface layer. Since more influencing factors are considered in the prediction formulation of fatigue life, it can provide a supplement and theoretical support to the research and design of pavement structure.