地铁隧道盾构管片氯离子传输模型及特性分析

基于混凝土不同深度处的氯离子浓度分布测定试验,采用Matlab数值模拟方法研究了杂散电流对氯离子向地铁隧道盾构管片内传输性能的影响,并引入杂散电流影响系数建立了一种考虑杂散电流作用效应的氯离子扩散系数时变预测模型.结果表明:杂散电流明显加速了氯离子向地铁隧道盾构管片内的扩散,增大了混凝土不同深度处的氯离子含量.杂散电流对氯离子向地铁隧道盾构管片内传输性能的影响与杂散电流强度之间符合指数函数关系.模型计算结果和试验结果吻合良好.

Chloride Ion Transport Model and Properties Analysis of Subway Shield Tunnel Segment

The effect of stray current on transmission performance of chloride ion into shield segment of Metro Tunnel were investigated by Matlab simulation based of the determination of chloride concentration distribution at different depths of concrete.In addition,the time dependent prediction model of chloride diffusion coefficient in concrete influencing by stray current was established by introducing the influence coefficient of stray current.The study shows that, the diffusion of chloride ions into shield segments of metro tunnels and the chloride ion content at different depths of the concrete were obviously increased after stray currents action.The relationship between the effect of stray current on the transmission performance of chloride ion into the shield segment of subway tunnel and the stray current is accorded with exponential function.The results of model calculation have a good correlation with the measured results.