跨越结构层的反射裂缝扩展过程参数影响分析

Parameter Influence Analysis of Reflective Crack Propagation Process in Crossing Structure Layers

基于ABAQUS有限元软件和断裂力学分析理论,采用离散裂缝长度模拟反射裂缝扩展过程,针对裂缝由基层底扩展并跨越至面层顶时,不同结构层参数对裂缝尖端应力强度因子影响进行了分析,并通过工程实例进行了结构层参数优化设计计算。结果表明:在荷载作用下,基层底部往上存在一定范围的受拉区,受拉区裂缝将受到张拉和剪切的混合型作用,面层和基层参数的增大都会引起张拉型应力强度因子的增大,对早期裂缝控制不利;裂缝扩展后期,适当增大基层模量、厚度以及面层厚度可减小剪切型应力强度因子,其中适当增加面层厚度较明显;在防治反射裂缝扩展方面,在保证路面其他控制条件下,应选择较低的面层模量;工程实例的优化设计计算验证了前述结论。

Based on finite element software ABAQUS and the fracture mechanics,this paper firstly applies the discrete crack lengths method to simulate propagation process of reflective crack,then analyzes the influence of structure parameters on crack tip stress intensity factor by focusing on crack propagating from base bottom and across to surface top,and finally verifies the optimization design of structure layer parameters with an engineer-ing project. Results show that：Up above base bottom it has a range of tension zone under function of loading, which makes crack tip subjected to hybrid function of tension and shear in tension zone. Increase in surface and base parameters will increase tension type SIF of base crack against early crack control. During later period of crack propagation,appropriate increase in base modulus,thickness and surface thickness can reduce the shear type SIF,and the surface thickness is obvious. In terms of preventing reflective crack extension,the lower sur-face modulus might be used to ensure other conditions control in pavement design.