柔性路面的各向异性疲劳损伤数值模型研究

根据柔性路面在交通荷载作用下的力学响应特点,推导了一个各向异性疲劳损伤本构方程,并基于ABAQUS软件及其二次开发平台,建立了考虑各向异性疲劳损伤的路面结构有限元模型。通过建立的模型计算车辆作用下路面结构的疲劳寿命,其结果与试验数据吻合良好,误差最高仅为3.8%,证明该模型精确可靠。最后,分析了疲劳损伤的演化规律,以及路面结构参数对疲劳性能的影响。结果表明,路面纵向疲劳损伤演化速率比横向大得多,随着车辆循环作用,路面结构的各向异性逐渐增强,进而又加剧疲劳损伤的演化。另外,沥青层越厚、土基弹性模量越大,路面疲劳损伤演化得越慢;而当土基较弱、沥青层较薄时,增加级配碎石层厚度可以显著延缓柔性路面的疲劳开裂。

Study on numerical model of anisotropic fatigue damage of flexible pavement

Assuming fatigue damage in flexible pavement structure as anisotropic;the constitutive equation considering the anisotropic fatigue damage was derived.By using the general finite element software ABAQUS and the secondary development platform,a flexible pavement finite element model which considered the anisotropic fatigue damage was established.Adopting the model,fatigue life of pavement structure under repeated load was calculated.The results were in good agreement with the test and the maximum error is only 3.8%.Then the fatigue damage evolution law of pavement structure under repeated vehicle load was studied based on this model.At last,how pavement structure parameters influencing the pavement fatigue performance was analyzed.The results indicate that the longitudinal fatigue damage evolution of the pavement is much faster than that of the transverse direction.With the increase of load circles,the anisotropy of pavement structure increases gradually which in turn aggravates the fatigue damage evolution.The thicker asphalt layer and the greater subgrade strength are,the slower the pavement fatigue damage evolution is.Fatigue cracking of flexible pavement can be significantly delayed when the foundation is weak and the asphalt layer is thin.