混凝土桥梁氯离子侵蚀过程仿真的细胞自动机模型

Cellular Automata-based Model for Simulating the Chloride Ion Penetration Process of Concrete Bridge

为准确高效地模拟钢筋混凝土桥梁在运营期间氯离子的侵蚀过程,并获得梁截面内任意时刻任意位置的氯离子浓度,提出基于细胞自动机理论的混凝土桥梁氯离子侵蚀过程模拟方法.首先,根据细胞自动机原理对氯离子侵蚀过程进行分析,利用简单的局部进化行为模拟复杂的扩散过程.然后,综合考虑时空变异性、水灰比、应力状态等因素对氯离子侵蚀过程的影响,建立多因素耦合作用下的混凝土桥梁的氯离子侵蚀模型.最后,以某T梁为例,分析桥梁服役期间氯离子扩散规律及混凝土水灰比和应力状态对氯离子扩散过程的影响.结果表明,钢筋表面的氯离子浓度值在侵蚀20年时开始趋于稳定,角部区域钢筋更易锈蚀;混凝土水灰比越大,钢筋表面的氯离子浓度增长越快;梁截面拉应力越大,钢筋表面的氯离子浓度增长越快,而压应力越大,钢筋表面的氯离子浓度增长越缓慢.

To simulate the chloride ion penetration in concrete bridge during the service stage accurately and efficiently, and acquire the values of chloride ion concentration at any time, a Cellular Automata （CA）-based model was proposed. Firstly, the process of chloride ion penetration was analyzed by the CA method and a local evolvement law was used to describe the complex process of chloride ion penetration in concrete bridge. In addition, considering the impact of various factors such as temporal variability, spatial variability, water-cement ratio and stress situation on the process of chloride ion penetration, the model of chloride ion penetration under multi-factor coupling was presented. Finally, a T-type beam was taken as an illustrative example to analyze the process of chloride ion penetration. The results showed that ： chloride ion concentration outside the reinforcements tended to be stable after 20 years, and the corner reinforcements were corroded more easily;the higher the water-cement ratio or the tensile stress was, the faster the speed of chloride ion outside the reinforcement increased; while the higher the compressive stress, the speed of chloride ion outside the reinforcement increased slower.