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【目的】研究沥青路面表面裂缝在动荷载作用下的扩展行为,分析完整沥青路面结构和含表面裂缝结构的负荷响应,探讨应力强度因子K2随着荷载变化的规律,以及表面裂缝在扩展过程中K2的敏感性,为公路工程中路面结构抗裂设计提供一定理论依据。【方法】应用有限元软件ABAQUS建立沥青路面表面裂缝结构模型,基于动力学理论对交通荷载作用下沥青路面结构进行数值计算。【结果】动荷载作用下,完整沥青路面的表面弯沉较静态荷载有所减小,随着裂缝扩展深度的增大,弯沉值会逐渐增大;动应力强度因子K2的变化曲线较荷载变化曲线具有一定的滞后性,且最大值大于静态荷载下K2的值;表面裂缝向下扩展过程中,K2在扩展前期增长速率较快,扩展至面板厚度一半后,K2的增长速率逐渐放缓;减小面层模量、增大基层模量和厚度,能够较好地抑制表面裂缝的扩展,其余参数则影响较小;K2随着行车荷载的增大呈线性增长趋势,裂缝扩展越深K2增加越显著。【结论】延长含表面裂缝的沥青路面结构的使用寿命,较好的方法是减小面层动态模量,适当增大基层的动态模量以及增大基层的厚度。
【Objective】 The purpose of this study is to investigate the spreading behavior of surface cracks of asphalt pavement under dynamic load and to analyze the load response of intact asphalt pavement structure and surface crack structure and to investigate the regularity of stress intensity factor K2 changing with load and the influence of surface cracks in the spreading process K2 sensitivity for highway engineering pavement crack design provide a theoretical basis. 【Method】 The finite element software ABAQUS was used to establish the crack model of asphalt pavement surface. Based on the dynamic theory, the asphalt pavement structure under the traffic load was numerically calculated. 【Result】 The results show that the surface deflection of the intact asphalt pavement is less than that of the static one under the action of dynamic load. The deflection will gradually increase with the increase of the crack propagation depth. The curve of dynamic stress intensity factor K2 is more stable than the load And the maximum value is larger than the value of K2 under static load. During the downward expansion of surface cracks, the growth rate of K2 increases rapidly in the early stage of expansion, and the growth rate of K2 gradually slows down after extending to half of the panel thickness ; Reducing the surface modulus and increasing the modulus and thickness of the basement can restrain the expansion of the surface cracks better, while the other parameters have less influence; K2 increases linearly with the increase of driving load, and the crack propagation is deeper K2 more significant increase. 【Conclusion】 It is a better method to extend the service life of the asphalt pavement structure with surface cracks by reducing the dynamic modulus of the surface layer, increasing the dynamic modulus of the base layer and increasing the thickness of the base layer.