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为揭示钢桥面沥青混凝土铺装裂缝行为机理,分析了铺装层疲劳裂缝扩展阻力曲线,利用复合梁疲劳试验数据,采用三维有限元方法,研究了铺装层裂缝启裂、扩展直至失稳的全过程。结果表明:疲劳裂缝扩展阻力曲线形式与材料类型和“铺装层+钢板”复合结构有关系;当天然初始裂缝长度为0时,疲劳裂缝扩展一般存在3个阶段:起始扩展区、稳态扩展区和失稳扩展区,此时复合梁的疲劳寿命接近800万次;当初始裂缝长度为10 mm时,疲劳裂缝扩展直接进入失稳扩展区,疲劳寿命约为200万次;裂缝增长率与荷载作用次数之间存在良好的非线性关系。可见,钢桥面铺装层宜选用空隙率小、易密实的铺装材料,同时可根据荷载作用次数推断出铺装层疲劳裂缝的状态。
In order to reveal the crack propagation mechanism of asphalt pavement on steel bridge deck, the fatigue crack propagation resistance curve of pavement was analyzed. Based on the fatigue test data of the composite beam, the crack initiation and propagation of the pavement layer was studied by three-dimensional finite element method The whole process. The results show that the form of fatigue crack propagation resistance is related to the type of material and the “pavement + steel plate” composite structure. When the length of natural initial crack is 0, the fatigue crack propagation generally has three stages: initial expansion zone, The steady state extended area and the unstable expanded area, the fatigue life of the composite beam is nearly 8 million times. When the initial crack length is 10 mm, the fatigue crack extends directly into the unstable expanding area and the fatigue life is about 2 million times. There is a good non-linear relationship between the rate of growth and the number of loadings. Visible, steel deck pavement should choose a small porosity, easy to dense pavement materials, and can be based on the number of loads to infer the status of the fatigue crack pavement.