腐蚀离子环境中盾构隧道衬砌结构侵蚀劣化机理  

Erosion Degradation Mechanism of Shield Tunnel Lining Structure in Corrosive Ion Environment

作　　者：刘四进[1] 何川[1] 孙齐[1] 封坤[1] 陈小坚 

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室,四川成都610031 [2]厦门轨道交通集团有限公司,福建厦门361002

出　　处：《中国公路学报》2017年第8期125-133,共9页China Journal of Highway and Transport

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)

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。In order to reveal the erosion degradation mechanism of shield tunnel lining structure under the long-term coupling effect of the external water pressure and the surrounding corrosive ion environment,the penetration depth of the porous concrete and the ion erosion migration of the concrete under the pressure penetration were analyzed theoretically.Whist the numerical model of the ion erosion convection-dispersion migration of the segment joint was established.Then,the rationality of the ion erosion theory considering the effect of pressure permeation was verified at the one-dimensional seepage state.Furthermore,the numerical model of ion erosion of shield tunnel lining structure in consideration of pressure permeation,ion convection-dispersion migration and the discontinuous segment joint was established.The focal point lied in the analysison the erosion and deterioration of the whole segmental lining structure.The results show that the existence of water pressure has a positive effect on the seawater permeation.The higher the external water pressure is,the more obvious the effect of seawater penetration can be.The increase of external water pressure leads to the increase of chloride ion content.The higher the external water pressure is,the shorter accumulation time required for accumulating to the same ion concentration in the same position can be.The ion content distribution of the segment joint has the characteristic of local concentration.The ion erosion degree of the whole lining structure from small to large is vault,hance and the bottom of arch.At the beginning of the service,only steel bars in the vicinity of joints are corroded,and then the other parts of steel bars are almost unevenly corroded.With the extension of service time,the difference of the uneven corrosion decreases.

关 键 词：盾构隧道 腐蚀离子 离子对流-弥散运移数值模型 压力渗透 侵蚀劣化 

分 类 号：U457.5[建筑科学—桥梁与隧道工程]