基于双裂缝模型的沥青道路裂缝间应力强度因子的影响因素分析

Analysis on influencing factors of stress intensity factor between cracks of asphalt road based on double crack model

沥青道路旧裂缝周边往往会产生新的裂缝,从而演变为间距较短的平行裂缝。为研究不同温度及车辆荷载下旧裂缝对新裂缝应力强度因子的影响,对道路三维双裂缝模型进行有限元数值模拟,分析裂缝类型、裂缝间距及荷载形式等因素对裂缝尖端应力强度因子的影响关系。结果表明:低温时已有的面层裂缝或面层-基层贯穿裂缝会显著增加近距离(约在0.25m内)基层裂缝上边缘的应力强度因子,车辆荷载下已有的面层裂缝或面层-基层贯穿裂缝同样会增加近距离(约在0.25m内)面层裂缝下边缘的应力强度因子。因此,面层-基层贯穿裂缝会显著促进周边面层裂缝或基层裂缝的扩展。

The new cracks are often generated around the old cracks of asphalt road,thus evolving into parallel cracks with short gap.In order to investigate the influence of old cracks on stress intensity factor of new cracks under different temperature and vehicle load,finite element numerical simulation was carried out for 3D double crack model of the road to analyze the impacts of crack type,crack interval and load form on stress intensity factor of crack tip.The results show that the existing surface cracks or surfacebase penetrating cracks at a low temperature can significantly increase the stress intensity factor of the upper edge of the base cracks in the short distance range about 0.25 m,and the existing surface cracks or surface-base penetrating cracks under vehicle load will also increase the stress intensity factor of the lower edge of the surface cracks in the short distance range about 0.25 m.Therefore,surface-base penetrating cracks will significantly promote the expansion of surrounding surface cracks or base cracks.