This paper analyzes relaxation characteristics of asphalt pavement with reflective crack under traffic load and reveals the failure mechanism. Based on the thermorheological simplicity of viscoelastic materials,relaxation moduli function under differential temperature for asphalt concrete are determined. The elements are locally refined in order to simulate crack. Normal stress is reduced with time, and stress relaxation is obvious. Change extent of shearing stress at the surface bottom with time and distance from crack tip is obvieus. Change extent of maximum vertical deflection is not obvious with relaxation. Normal stress is not obvious with relaxation. The chief reason of crack propagated under symmetrical load is normal stress, not shearing stress. Change extent of maximum vertical deflection is not obvious with relaxation.%目的 研究含裂缝沥青混凝土路面在行车载荷作用下的松弛特性,揭示其破坏机理.方法 根据时温等效原理确定沥青混合料的松弛参数,采取逐级加密的方法划分网格来模拟裂缝,应用数值模拟的方法分析行车载荷作用下沥青混凝土路面松弛特性.结果 各点的正应力随时间的延长而减小,表现出明显的应力松弛现象;面层底部的切应力随距裂尖距离没有明显的规律;路表弯沉随松弛时间的变化也没有明显的规律.结论 正应力随着松弛时间而减小,表现出明显的应力松弛特性;在对称载荷的作用下,反射裂缝扩展的主要因素是正应力,而不是切应力;松弛对路表弯沉的影响不大.
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