半刚性基层沥青路面U形破坏力学机理分析

Mechanical Analysis on U-shaped Cracking of Semi-rigid Base Asphalt Pavement

沥青路面层间粘结不足易导致层间滑移病害的发生,U形破坏是纵向层间滑移的典型破坏形式,多发生在车辆频繁加速、减速的长大纵坡路段。以半刚性基层沥青路面U形开裂为研究对象,采用有限元分析软件ABAQUS,计算了模型在荷载作用下的力学响应,分析了应力在路面内的分布规律,结合路面实际破坏现象,揭示了U形破坏产生的力学机理。经过分析得知:纵向拉应力和剪应力的分布规律分别与U形裂缝的底部和两侧位置相吻合,且U形底部开裂是拉应力导致的张开型裂缝,U形的两侧开裂是剪应力导致的剪切型裂缝。

Poor bond between two layers of asphalt pavement is the main cause of slippage failure.U-shaped cracking which often occurring at locations where traffic accelerates and decelerates continually,is the most commonly observed typical problem related to slippage failure between layers.This paper developed a mechanical model of the semi-rigid base asphalt pavement by a finite element program（ABAQUS）.The pavement structure mechanical responses under traffic were computed and the regularities of stress distribution of pavement were analyzed.The characteristics of U-shaped cracking disease on asphalt pavement were described. Combined with the mechanical analysis results,the paper revealed the mechanism of the U-shaped cracking.The results show the distribution regularities of tensile stress and horizontal shear stress at longitudinal direction are coincident with the bottom and bilateral areas of U-shaped cracking,respectively.The bottom cracks of U-shaped cracking are of opening mode caused by tensile stress,and the bilateral cracks of U-shaped cracking are of shearing mode caused by shear stress.