半刚性基层沥青路面温缩型反射裂缝的扩展机理分析

Development Mechanism Analysis of Temperature Shrinkage Type Reflective Crack in Asphalt Pavement on Semi-rigid Base

通过对半刚性基层在温度应力作用下裂缝扩展机理的分析,以线弹性断裂力学理论和有限单元方法为基础、利用ANSYS计算软件,研究了产生反射裂缝的力学机理,分析了各参数对含裂纹路面结构的应力场以及裂纹尖端应力强度因子的影响。结果表明,得出裂纹尖端的应力集中是导致裂缝向上扩展的根本原因,降低基层材料的弹性模量能抑制或延缓基层裂缝的扩展;当裂缝已经反射到面层后,降低面层材料的弹性模量也可以起到抑制或延缓基层裂缝的扩展;同时,外界环境和路面结构对裂缝的扩展亦有较大的影响,应根据当地的气候条件合理地设计沥青面层和基层的厚度,以保证路面结构具有预期设计的抗裂性。为防止或减少反射性裂缝有重要的参考价值。

Semi-rigid base can be crazed by temperature and humidity change, these cracks will extend to road surface because of the effect of temperature stress, the study into the mechanism of propagation upward of cracking holds great significance to both academic research and practical project. Based on the theory of elastic fracture mechanics and FEM, the mechanical mechanism of reflective cracks was investigated by using the ANSYS software, and the effect of respective parameters on the stress field and the crack tip stress intensity factor of cracked pavement was analyzed. Some important conclusions show that stress concentration of cracking tip is the root cause of propagation upward of cracking, and the elastic modulus, ambient condition and structure of pavement have great effect on the propagation of reflective cracking. The research is an important reference for mitigating the reflective cracking.