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研究混凝土寿命预测对其结构可靠度以及服役寿命非常重要。针对基础工程中的混凝土结构材料在现场暴露环境下的寿命预测问题,提出了一种基于Copula函数的多退化因素剩余寿命预测方法。首先,选取质量损失和超声声速作为关键的退化因素,接着针对退化因素间不同的退化轨迹,采用不同的方法对实际采集的数据进行退化建模,得到了混凝土剩余寿命的边缘分布函数。然后,通过Copula函数来建立退化因素之间的相关关系,将得到的剩余寿命的边缘分布进行融合,得到了混凝土剩余寿命的联合分布函数。最后,结果表明:选择质量损失和超声声速退化因素有助于建立混凝土在现场环境下的退化模型,并得到相应剩余寿命的边缘分布函数;混凝土在西宁现场暴露环境下的使用寿命约为225月,损伤发展开始于约第180个月;该方法充分利用现场数据为现场复杂环境下的混凝土寿命预测提供了一个新思路和新方法,具有一定的适用性和可行性。
Studying the life prediction of concrete is very important to its structural reliability and service life. Aiming at the problem of life prediction of concrete structural materials exposed to the environment in the foundation engineering, a method based on Copula function is proposed to predict the remaining life of multi-degradation elements. First of all, mass loss and ultrasonic velocity are selected as the key degradation factors. Then, different methods are used to degenerate the actual collected data according to the different degradation trajectories of degradation factors, and the edge distribution function of residual life of concrete is obtained. Then, by Copula function to establish the correlation between the degradation factors, the edge distribution of the remaining life is obtained, and the joint distribution function of the remaining life of the concrete is obtained. Finally, the results show that: the choice of mass loss and ultrasonic velocity degradation factors contribute to the establishment of concrete in the field environment degradation model, and the corresponding edge of the residual life distribution function; concrete in Xining on-site exposure to life of about 225 months The damage development started at about the 180th month. This method fully utilizes the field data to provide a new idea and a new method for the prediction of the concrete life under the complex environment, which has a certain applicability and feasibility.