基于细观尺寸受损路面混凝土疲劳寿命预测研究

发布时间：2018-03-10 23:45

本文选题：路面混凝土　切入点：疲劳损伤　出处：《长安大学》2015年硕士论文　论文类型：学位论文

【摘要】：水泥混凝土路面是我国公路重要组成部分,然而随着混凝土路面通车里程的增加,早期疲劳开裂现象越来越明显,主要原因是混凝土宏观疲劳引发细观结构损伤,而细观损伤累积导致混凝土路面发生宏观疲劳开裂。所以通过研究路面混凝土细观损伤,准确预估剩余疲劳寿命,提前做好防护措施,对于延长水泥混凝土路面使用寿命有着非常重要的意义。本文通过研究混凝土路面疲劳损伤演化机理,借助有效应力重分布效应,引入损伤变量因子,运用基于唯象学连续介质损伤理论,考虑多级不同应力水平下循环加载累积损伤作用,给出路面损伤量确定方法,建立考虑细观损伤的路面混凝土疲劳模型,预估路面混凝土疲劳寿命,完善混凝土路面设计,推动混凝土路面的发展。主要研究结论如下:(1)通过对混凝土损伤本构模型的分析,得出选取Kachanov损伤模型更适用于混凝土细观损伤疲劳模型的研究。总结混凝土疲劳累积损伤理论,选用Miner准则可以较好的确定混凝土路面的损伤量。(2)通过研究混凝土疲劳损伤演化机理,基于混凝土材料应力跌落与有效应力重分布机制,得出疲劳过程中有效应力重分布效应与损伤的关系,建立受损路面混凝土真实有效应力水平与损伤变量的表达式。(3)分析多级荷载应力下路面混凝土疲劳特性,考虑有效应力重分布效应,引入损伤变量因子,基于混凝土疲劳损伤理论,推导出含有损伤变量因子的路面混凝土疲劳模型。通过现场交通量调查,采用Miner准则可以确定使用基准期的累积损伤量,再根据疲劳损伤模型可以预估设计期内混凝土疲劳剩余寿命。(4)通过调查T高速公路K8+900段交通量,预估受损混凝土路面疲劳寿命,将疲劳损伤方程确定的疲劳寿命与疲劳试验测定的疲劳寿命对比,得出采用基于细观损伤变量的混凝土疲劳模型可以较为准确的预估混凝土剩余疲劳寿命。
[Abstract]:Cement concrete pavement is an important part of highway in China. However, with the increase of mileage of concrete pavement, the phenomenon of early fatigue cracking becomes more and more obvious. However, the accumulation of meso-damage leads to macroscopic fatigue cracking on concrete pavement. Therefore, by studying the microscopic damage of pavement concrete, the residual fatigue life can be accurately estimated, and protective measures will be taken in advance. It is of great significance to prolong the service life of cement concrete pavement. In this paper, the damage variable factor is introduced by studying the evolution mechanism of fatigue damage of cement concrete pavement and the effect of effective stress redistribution. Based on the phenomenological continuum damage theory and considering the cumulative damage under cyclic loading at different stress levels, the method of determining pavement damage is presented, and the fatigue model of pavement concrete considering meso-damage is established. The fatigue life of pavement concrete is predicted, the design of concrete pavement is improved, and the development of concrete pavement is promoted. The main conclusions are as follows: 1) through the analysis of constitutive model of concrete damage, It is concluded that the Kachanov damage model is more suitable for the study of microscopic damage fatigue model of concrete, and the fatigue cumulative damage theory of concrete is summarized. Miner criterion can be used to determine the damage amount of concrete pavement. Based on the mechanism of stress drop and effective stress redistribution of concrete material, the mechanism of fatigue damage evolution of concrete is studied. The relationship between the effect of effective stress redistribution and damage during fatigue is obtained, and the expression of true effective stress level and damage variable of damaged pavement concrete is established. The fatigue characteristics of pavement concrete under multistage load stress are analyzed. Considering the effect of effective stress redistribution, the damage variable factor is introduced. Based on the theory of concrete fatigue damage, the fatigue model of pavement concrete with damage variable factor is derived. The cumulative damage amount in the base period can be determined by using the Miner criterion, and the residual fatigue life of concrete during the design period can be estimated according to the fatigue damage model. The fatigue life of damaged concrete pavement is predicted, and the fatigue life determined by fatigue damage equation is compared with the fatigue life measured by fatigue test. It is concluded that the concrete fatigue life can be predicted accurately by using the concrete fatigue model based on the meso-damage variable.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U418.6

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