采用损伤力学方法研究沥青混合料的疲劳失效问题。针对悬壁梁弯曲疲劳试件，推导出疲劳过程中应力场、损伤场和疲劳裂纹形成寿命的工程封闭公式。根据沥青混合料特点，提出一种模拟疲劳裂纹扩展的特征单元失效模式，从而将疲劳裂纹形成与扩展两个阶段统一用损伤力学理论进行描述和分析。本文对沥青混合料试件的疲劳裂纹形成寿命与扩展寿命分段进行了预测，还对疲劳过程中刚度衰减及位移幅值的演化过程进行了数值模拟计算。理论预期与实验结果吻合良好。 Study on fatigue failure of asphalt mixture by damage mechanics method. Aiming at the bending fatigue specimens of cantilever beams, engineering closure formulas of stress fields, damage fields and fatigue cracks during fatigue are deduced. According to the characteristics of asphalt mixture, a failure mode of characteristic element to simulate fatigue crack growth is proposed, and the damage mechanics theory is described and analyzed in two stages of formation and propagation of fatigue crack. In this paper, the fatigue crack initiation life and extended life span of asphalt mixture specimens are predicted, and the numerical simulation of the attenuation of stiffness and the evolution of displacement amplitude are also carried out. The theoretical expectation is in good agreement with the experimental results.