腐蚀离子环境中盾构隧道衬砌结构侵蚀劣化机理

发布时间：2018-03-11 09:30

本文选题：盾构隧道　切入点：腐蚀离子　出处：《中国公路学报》2017年08期 　论文类型：期刊论文

【摘要】：为揭示外水压与周围腐蚀离子环境长期耦合作用下盾构隧道衬砌结构侵蚀劣化机理,对压力渗透下管片混凝土多孔介质渗透深度与离子侵蚀运移进行理论解析,建立管片接头离子侵蚀对流-弥散运移数值模型,在一维渗流状态下验证了考虑压力渗透作用的腐蚀离子侵蚀理论的合理性,并建立可考虑压力渗透、离子对流-弥散运移以及管片接头非连续的盾构隧道衬砌结构离子侵蚀数值模型,重点分析了整环管片衬砌结构侵蚀劣化规律。结果表明:水压力的存在对海水渗透具有促进作用,外水压力越大,对海水渗透效果越显著;外水压力的增大将导致氯离子含量的增加,外水压力越大,同一位置累积到相同离子浓度所需的累积时间越短;管片接头处离子含量分布具有局部集中的特点,整环管片衬砌结构离子侵蚀大小关系为拱顶拱腰拱底;服役初期仅管片接头附近外排钢筋出现锈蚀,而后出现外排钢筋整体性锈蚀,体现出不均匀锈蚀的特点,且随着服役时间的延长,外排钢筋不均匀锈蚀差异减小。
[Abstract]:In order to reveal the erosion deterioration mechanism of shield tunnel lining under the long-term coupling of external water pressure and surrounding corrosion ion environment, the permeation depth and ion erosion migration of porous media in segmented concrete under pressure permeation were analyzed theoretically. A numerical model of ion erosion convection-dispersion migration in segment joints is established. The rationality of corrosion ion erosion theory considering pressure permeation is verified under the condition of one-dimensional seepage, and the pressure permeation can be taken into account. Numerical model of ion erosion for shield tunnel lining structure with ion convection dispersion migration and segment joint discontinuity. The results show that the existence of water pressure can promote seawater permeability, and the higher the external water pressure, the more significant the effect of seawater permeation. The increase of external water pressure will lead to the increase of chloride ion content. The higher the external water pressure, the shorter the accumulation time required to accumulate to the same ion concentration at the same position. The relationship of ion erosion of the whole ring segment lining structure is the arch top arch waist arch bottom, in the early stage of service only the steel bar outside the segment joint is corroded, and then the external steel bar is corroded as a whole, which shows the characteristics of uneven corrosion. And with the extension of service time, the uneven corrosion difference of steel bars decreased.
【作者单位】：西南交通大学交通隧道工程教育部重点实验室;厦门轨道交通集团有限公司;
【基金】：国家重点研发计划项目(2016YFC0802201) 中国工程院重点咨询项目(2015-XZ-28-02) 国家自然科学基金项目(51578462) 厦门市科技计划重大项目(3502Z20151006)
【分类号】：U455.43

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