含界面裂隙的沥青混凝土路面疲劳寿命研究

发布时间：2018-02-03 01:05

本文关键词： 沥青路面层间裂隙断裂力学应力强度因子疲劳试验疲劳寿命　出处：《重庆交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：传统的路面设计中，通常假定沥青路面各结构层之间完全连续接触，然而，现投入使用的大量半刚性基层沥青路面中，由于材料或者施工因素的影响，导致结构层间不连续状态的产生，形成了层间界面裂隙。界面裂隙的存在，改变了路面结构在竖直方向上的连续状态，，并削弱结构的强度以及疲劳特性。本文以断裂力学理论为基础，采用试验研究与数值模拟相结合的方法，研究界面裂隙对路面结构疲劳寿命的影响。论文对基层与面层材料进行断裂韧性测试。通过三点弯曲断裂试验可知，断裂韧度KIC不会因为测量方法和试件尺寸的改变而改变，同时验证了柔度标定法测量应力强度因子的可行性。论文通过含有预制界面裂隙的水泥稳定碎石-沥青混凝土小梁的三点弯曲疲劳试验，分析小梁的疲劳破坏特征，研究了三点弯曲小梁的疲劳寿命与疲劳断裂路径。试验结果表明：界面裂隙在一定程度上降低了结构的强度与疲劳寿命，而且随着裂隙长度的增加，这种效果越加明显；应力比的越大，起裂出现的位置越靠近中间部位，裂缝的延伸方向越垂直上下表面，裂缝的曲折发展越少。论文采用线弹性断裂力学与有限元软件ANSYS相结合的方法，分析在荷载作用下，界面裂隙尖端的应力强度因子变化规律，并计算不同初始长度裂隙的扩展寿命。结果表明：随着裂隙的不断扩展，张拉应力强度因子KI不断增大，剪切应力强度因子KII不断减小,等效应力强度因子呈线性关系增大，裂隙尖端呈现张开型和剪切型共同作用的复合型扩展模式;按照Paris公式计算得到在相同扩展长度下，裂隙的疲劳扩展寿命随着初始长度的不断增大而减小。论文得到了交通土建工程材料国家地方联合工程实验室开放基金项目“沥青路面结构层层间界面形态和细观力学行为与路面疲劳损伤关系研究”的资助。
[Abstract]:In the traditional pavement design, it is usually assumed that there is a complete continuous contact between the structural layers of the asphalt pavement. However, a large number of semi-rigid base asphalt pavement in use now, due to the impact of materials or construction factors. It leads to the discontinuous state of the structure and the formation of interlayer interface crack. The existence of the interface crack changes the continuous state of the pavement structure in the vertical direction. Based on the theory of fracture mechanics, the influence of interface crack on fatigue life of pavement structure is studied by means of experimental study and numerical simulation. Through the three-point bending fracture test, the fracture toughness KIC will not change because of the change of measurement method and specimen size. At the same time, the feasibility of measuring the stress intensity factor by the flexibility calibration method is verified. Through the three-point bending fatigue test of cement stabilized macadam and asphalt concrete trabeculae with precast interface cracks, the fatigue failure characteristics of trabeculae are analyzed in this paper. The fatigue life and fatigue fracture path of three-point bending trabeculae are studied. The experimental results show that the interface fracture reduces the strength and fatigue life of the structure to some extent and increases with the length of fracture. This effect is more obvious; The greater the stress ratio, the closer the position of the initiation crack to the middle part, the more vertical the upper and lower surface of the crack, and the less the tortuous development of the crack. In this paper, the linear elastic fracture mechanics and the finite element software ANSYS are used to analyze the stress intensity factor variation law of the interface crack tip under load. The results show that the tensile stress intensity factor (Ki) increases and the shear stress intensity factor (KII) decreases as the crack expands. The equivalent stress intensity factor increases linearly, and the crack tip shows a compound expansion model of the joint action of open type and shear type. According to the Paris formula, it is found that the fatigue propagation life of fracture decreases with the increase of initial length under the same propagation length. In this paper, the open fund project of national local joint engineering laboratory of traffic civil engineering materials "study on the relationship between the interfacial morphology and meso-mechanical behavior of asphalt pavement structure and pavement fatigue damage" is obtained.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.21

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