氯蚀环境下钢混沉管隧道结构时变性态研究  

Study on Time-varying Behavior of Reinforced Concrete Immersed Tunnel Structure in Chlorine Corrosion Environment

作　　者：李硕标[1,2] 丁文其[1,2] 黄煊博 郭英杰 张清照[1,2] LI Shuo-biao;DING Wen-qi;HUANG Xuan-bo;GUO Ying-jie;ZHANG Qing-zhao(Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092

出　　处：《中国公路学报》2022年第10期55-64,共10页China Journal of Highway and Transport

基　　金：上海市“科技创新行动计划”社会发展科技攻关项目(20dz1202600);国家自然科学基金重大项目(52090083)。

摘　　要：作为重大公共交通基础设施,跨海沉管隧道需具备良好的耐久性能,但在海洋氯蚀环境下隧道结构寿命预测及结构服役时变演化特性方面的研究尚存不足。为此,根据氯离子在混凝土中的扩散规律及钢筋混凝土的氯蚀机理,推导了基于正常使用极限状态的沉管隧道钢筋混凝土衬砌在氯蚀环境下的寿命预测计算模型,并根据相关规范细化了该预测模型的主要参数。在此基础上进一步推导建立了隧道结构钢筋锈蚀率和混凝土弹性模量衰减的时变模型,用于计算不同服役时长下隧道结构钢筋和混凝土的材料参数并作为有限元模型的输入参数。最后,将隧道寿命预测模型及结构时变模型应用于大连某钢混沉管隧道工程,预测该隧道的服役寿命,并分析隧道衬砌材料及结构力学性态随服役时长的时变特性。研究结果表明:①隧道钢筋锈蚀率和混凝土弹性模量衰减率随腐蚀时长均呈现三折线加速上升;②随着服役(氯蚀劣化)时长增加,沉管隧道拱顶跨中位置的内力(弯矩、轴力)逐渐减小,而沉降变形逐步增加;③沉管结构塑性区先出现在结构受拉部位,且在混凝土表面锈蚀胀裂前塑性区基本未发生扩大,而在混凝土表面被钢筋锈蚀胀裂后开始逐步扩大,并在结构受压部位出现塑性区;④在沉管结构受压部位出现塑性区前结构受压部位的最大Mises应力随服役时长不断增加,而在结构受压部位出现塑性区后结构的最大Mises应力加速下降。As an important public transport infrastructure,a subsea immersed tunnel should have good durability,but there are still deficiencies in the research on the life prediction and time-varying characteristics of immersed tunnel structures in a marine chlorine environment.This study used the diffusion law of chloride ions in concrete and the chlorine corrosion mechanism of reinforced concrete to develop a life prediction model for the reinforced concrete lining of an immersed tunnel under a chlorine corrosion environment based on the normal service limit state,and refined the main parameters of this prediction model based on the relevant specifications.Then,time-varying models of the reinforcement corrosion rate and concrete elastic modulus attenuation rate of a tunnel structure were established,which could be used to calculate the material parameters of tunnel structure reinforcement and concrete with different service times as the input parameters of the finite element model.Finally,the tunnel life prediction model and structural time-varying model were applied to a reinforced concrete immersed tunnel project in Dalian to predict its service life,and the time-varying mechanical behaviors of the tunnel lining materials and structures were analyzed.The results showed that①the corrosion rate of the tunnel reinforcement and attenuation rate of the concrete elastic modulus increased nonlinearly in three stages with an increase in the corrosion time;②with an increase in the service time(chlorine corrosion time),the internal force(bending moment and axial force)at the mid span of the vault of the immersed tunnel gradually decreased,while the settlement deformation gradually increased;③the plastic zone of the immersed tunnel structure first appeared in the tensile part of the structure,and this plastic zone hardly expanded before the expansion cracking of the concrete surface,but gradually expanded after the expansion cracking of the reinforcement rust on the concrete surface,and then appeared in the compression part

关 键 词：隧道工程 沉管隧道 时变模型 解析与数值方法 时变特性 力学性态 

分 类 号：U451.4[建筑科学—桥梁与隧道工程]