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为了研究在水-荷载耦合作用下沥青混合料试件的压缩疲劳破坏过程及其沥青路面结构的动力响应,借助CT扫描技术和图像处理技术,进行了无水和饱水沥青混合料的宏观和微观破坏初步对比分析,定量分析了破坏前后沥青、集料和空隙的变化情况。根据多孔介质理论,对广西典型半刚性沥青路面结构进行了ABAQUS建模和FLAC-3D的计算,分析了无水和饱水两种情况下的力学响应差异。结果表明:沥青混合料试件从无水向饱水转化时,破坏模式从压裂转变为剪切破坏模式;在行车荷载作用下,饱水沥青路面与其无水情况下力学响应特性的不同主要集中在沥青面层深度范围内;相对于无水情况,饱水情况荷载效应作用时间将会成倍增加,且沥青面层拉应力出现激增,使沥青路面更容易产生结构性损坏;饱水情况下的沥青路面层底产生较大的先压后拉的横向应变,导致沥青路面过早产生疲劳开裂。
In order to study the process of compressive fatigue failure and the dynamic response of asphalt pavement structure under the water-load coupling, the macroscopic and mechanical properties of water-free and saturated asphalt mixture were studied by means of CT scanning technology and image processing technology Preliminary comparative analysis of micro-damage, quantitative analysis of changes in asphalt, aggregate and voids before and after destruction. According to the theory of porous media, the ABAQUS modeling and FLAC-3D calculation of typical semi-rigid asphalt pavement structure in Guangxi were carried out. The difference of mechanical response under both anhydrous and saturated conditions was analyzed. The results show that the fracture mode changes from fracturing to shear failure mode when the asphalt mixture specimen is changed from anhydrous to saturated water. Under the driving load, the main difference between the mechanical response of saturated asphalt pavement and its anhydrous condition Concentrated in the asphalt surface depth range; relative to the case of water-free, saturated water load effect will double the role of time, and the asphalt surface tensile stress surge, so that the asphalt pavement more prone to structural damage; Under the asphalt pavement layer produces a greater pressure after the first pull the lateral strain, resulting in premature fatigue cracking of asphalt pavement.