基于数值模拟的半刚性基层沥青路面反射裂缝扩展路径分析

Numerical Simulation Analysis on Reflective Cracking Extended Path of Semi-rigid Base Asphalt Mixture

为了深入研究半刚性基层沥青路面反射裂缝的破损机理,应用离散元软件建立了半刚性基层复合结构模型,计算分析了裂缝尖端处的应力场,研究了在荷载作用下沥青路面裂缝的扩展规律,以及集料及空隙等沥青混合料细观结构因素对反射裂缝扩展路径的影响机理。结果表明：随着加载次数增加,裂缝尖端处应力降低,应变增加,黏结刚度下降,黏结损伤逐渐累积致使裂缝开展;规则对称的粗集料裂缝扩展会围绕集料对称地向上开裂,形状及相对位置不对称的集料反射裂缝会趋向于从损伤速率较快的一侧向上开裂;空隙会加剧裂缝尖端处的应力集中,裂缝会趋于向着空隙开展。

In order to study in-depth the damaged mechanism of reflective cracking of semi-rigid asphalt pavement,a discrete element method（DEM）is used to establish the compound structure model of semi-rigid base course,to calculate the stress field around the crack tip,and study the mechanism of cracking under vehicle load and the influence of the inner structure of mixture such as coarse aggregate and space on extended path of reflection crack.The results show that：with the increase of the number of loads,the stress at the crack tip reduces and strain increases,the bonding stiffness decreases and bonding damage gradually accumulated can cause cracks;cracks extend around the aggregate symmetrically upwards for regular symmetric coarse aggregate,and cracks tend to extend from the bonding damage faster side of upward for irregular asymmetry coarse aggregate;and space can increase the stress concentration at the tip of the crack,and cracks tend to extend towards the space.