【作者】 陈团结；

【导师】 黄卫； 钱振东；

【作者基本信息】 东南大学 ， 道路与铁道工程， 2006， 博士

【摘要】 钢桥面铺装层作为一个功能层,必须具有足够的强度和良好的整体性,并应具有足够的抗裂、抗冲击、耐磨性能。在我国,多座钢桥面铺装层在使用过程中都出现裂缝类病害,有的甚至严重到不得不进行大面积翻修。大跨径钢桥面铺装层出现裂缝之后,一旦雨水渗入裂缝,浸蚀铺装层与钢桥面板之间的粘结层,那么在行车荷载作用下,铺装层会很快在更大面积上开裂恶化,不但会诱发更多其他类型病害的产生,还会引起钢桥面板的锈蚀。这不仅对高速行驶车辆的安全构成威胁,而且会降低钢桥面板的使用寿命,同时也会造成恶劣的社会影响。因此,对钢桥面铺装层裂缝行为进行研究是降低铺装层病害出现的概率、延长铺装层使用寿命的关键。本文是国家自然科学基金项目“钢桥面环氧沥青混凝土铺装层疲劳损伤与寿命预估研究”(基金编号:50578038)的一部分,主要对环氧沥青混凝土铺装层裂缝行为进行理论研究。论文首先对环氧沥青混凝土裂缝类病害现场调查结果进行令了分析和评述。根据裂缝的具体特征把铺装层上的裂缝分为三类。在此基础上通过对钢桥面铺装层荷载图式的研究以及不同条件下铺装层的力学分析,得出了不同类型裂缝产生的机理,并对钢桥面铺装各种病害之间的演化关系进行了分析。在对现有材料断裂判据优劣性分析的基础上,利用有限元方法对带切口的环氧沥青混凝土复合结构的断裂过程进行了模拟,发现在J积分vs.裂缝扩展长度曲线上存在两个拐点,由此提出用J积分作为环氧沥青混凝土复合结构的断裂判据,同时给出了描述环氧沥青混凝土复合结构中裂缝扩展过程的指标:iniJ I和J Iun。疲劳断裂是环氧沥青混凝土铺装层裂缝出现的主要原因。材料的疲劳断裂过程实际上是多次动荷载作用下裂缝扩展过程的简单迭加。鉴于此,论文利用有限元方法对带裂缝的铺装层的动荷载响应进行了分析。同时分析了不同铺装层不平整度、裂缝深度、铺装层模量、铺装层与钢板之间层间粘结情况等对裂缝顶端应力场的影响,结果表明,不同因素对铺装层裂缝顶端应力场的影响规律是不同的。其中,铺装层与钢板之间的粘结情况对铺装层使用性能的影响最为显著。通过对已有研究成果的对比分析,对环氧沥青混凝土复合结构疲劳裂缝扩展阻力曲线的形式进行了探讨,并提出了适合于环氧沥青混凝土复合结构的R曲线。在此基础上,利用MSC.Fatigue对复合梁的疲劳裂缝扩展进行了研究,提出了疲劳裂缝扩展的三个阶段:启裂阶段、稳定扩展阶段和失稳扩展阶段,并分别对其进行了拟合,得出了疲劳裂缝扩展与疲劳荷载作用次数之间的关系。同时还提出了当量裂缝长度的概念,以有效考虑环氧沥青混凝土中的微孔隙对疲劳裂缝扩展的影响。研究裂缝的目的是控制并消除裂缝的不利影响。因此,论文在最后对利用分布式光纤传感器对铺装层中的裂缝进行监测并预报的可行性进行了分析,提出了分布式光纤传感器在铺装层中的布设方式。同时,对环氧沥青混凝土铺装层养护方法进行了分类,并对预防性养护方法的实用性进行了分析。并且建立了铺装层使用性能评价指标BPCI模型。利用BPCI的衰减规律,可以方便地进行养护决策。更多还原

【Abstract】 As a secondary layer, pavement on the steel orthotropic deck should have high strength, integrity and other good properties, such as anti-crack, anti-impaction, waterproof and wearable. In China, many steel deck pavements have the experiences of cracks during using, and some of them had to be rebuilt because of severe distresses. When cracks appearing in the deck pavement, rain or other water have the entrance to the bottom of the pavement and erode the cohesion layer between the pavement and steel deck. Gradually simple cracks will evolve into crocodile cracks or other distresses in wide area of the pavement under the traffic loadings, which may lead to the erosion of steel deck. This will not only do harm to the high speed vehicles, lower the fatigue life of the steel deck, but cause abominable social influence. Therefore, it is a key to put much effort into the analysis of cracks in pavement on the orthotropic steel deck, reducing the probability of cracking, and prolonging the life time of deck pavement.The dissertation is part of the project“Research on the Fatigue Damage and Life Prediction of Epoxy Asphalt Pavement on Steel Deck”(No. 50578038) aided by NSFC (National Natural Science Foundation of China). And the main purpose of the dissertation is doing theoretical research on the cracks of epoxy asphalt pavement.The distresses in epoxy asphalt pavement of orthotropic steel deck have been investigated, and cracks in the pavement were divided into 3 categories. The mechanism of each kind of cracks was analyzed on the basis of the research on the load patterns and different mechanic responses of the pavement with FEM. And the evolution relationship among different pavement distresses was discussed here.Composite beam made with epoxy asphalt over steel deck is the object of the research. The composite beam with a notch in the epoxy asphalt was simulated with FEM, and J-integral was used to evaluate the fracture property of the composite beam after considering the merit and demerit of the fracture criterions common used. The simulation results showed that there were two inflexions on the curve of J-integral vs. crack length, and J-integral could be a fracture criterion of the composite structure.As all known, fatigue fracture is the main cause of crack in the deck pavement. And the process of fatigue crack propagation is the addition of many times crack propagation under one-time dynamic loading. Therefore, the responses of epoxy asphalt pavement on steel deck with a crack were studied considering the stress field influenced by many factors such as different roughness of pavement, different crack depths, different pavement moduli and cohesion condition between deck and pavement.After the comparison among the research results, the R-curve of the composite structure was discussed and analyzed, on the basis of which fatigue crack propagation of composite structure was analyzed using MSC. Fatigue Programme. And the relationships between fatigue crack propagation vs. time of loading were regressed. And in order to considering the effect of the micro-void in the epoxy asphalt on the fatigue crack propagation, a new concept, Equivalent Crack Length, was put forward.The last topic in the paper was how to control crack and diminish its disbennifit effect. For the purpose, a new monitoring method, Distributed Fiber Crack Sensor, and the feasibility of how to use the fiber to monitor and predict pavement crack were discussed. Consequently some techniques of preventive maintenance and BPCI (Bridge Pavement Condition Index) model were recommended.更多还原