摘要
受侵蚀性地层环境的影响,隧道衬砌混凝土在长期服役过程中普遍存在混凝土腐蚀劣化、强度丧失等病害,严重危及隧道衬砌结构的稳定性以及行车的安全性。依托一实际铁路隧道工程,针对大面积腐蚀隧道衬砌结构,设计槽钢加固法修复方案并开展室内构件试验,获得加固修复后隧道衬砌构件的截面受力特征:试件柱中截面的轴向应变基本服从线性分布,可满足平截面假定;试件达到极限荷载时,受拉区边缘的混凝土表现出拉裂破坏特征,受拉侧由混凝土和槽钢共同提供拉应力,受压侧混凝土表现为脆性压溃破坏。进一步,根据截面受力特征将加固后试件的承载力划分为抗裂极限承载力和破坏极限承载力,推导得到槽钢加固法的承载能力计算方法。在此基础上建立数值模型,并将其结果与试验测试、理论简化方法进行对比分析,结果表明:3种方法计算得到的结果较为接近,最大偏差少于8%,说明建立的腐蚀构件加固后的承载力计算方法具有可靠性,可用于腐蚀衬砌加固的设计计算。最后,针对依托工程衬砌混凝土腐蚀深度≤10 cm的区段,开展修复方案设计与应用。具体方案为凿除衬砌表层10 cm厚的老旧混凝土,按纵向间距1 m埋设18#B槽钢,并通过膨胀螺栓与既有衬砌结构连接固定,回填C30微膨胀混凝土。按上述方案加固后,衬砌截面安全系数为3.6,可保障衬砌结构的安全稳定。
Under the influence of the erosive stratum environment,the tunnel lining concrete generally experiences the deterioration of concrete corrosion and the loss of strength during its long service,which seriously endangers the stability of tunnel lining structure and the safety of driving.This paper presented a repair scheme utilizing the channel steel reinforcement method for addressing large-scale corrosion of tunnel lining structure.An indoor component test was conducted to assess the section force characteristics of the reinforced and repaired tunnel lining components.The results indicate that the axial strain of the section in the column specimen basically follows a linear distribution,which can meet the assumption of flat section.When the specimens reached the ultimate load,the concrete on the edge of the tensile zone showed tensile cracking failure characteristics.The tensile stress on the tensile side was provided by concrete and channel steel,while the concrete on the compressive side showed brittle collapse failure.According to the mechanical characteristics of the section,the bearing capacity of the reinforced specimens was divided into the ultimate bearing capacity of cracking resistance and the ultimate bearing capacity of failure,and the calculation method of the bearing capacity of the channel reinforcement method was derived.On this basis,a numerical analysis model was established,and the results were compared with the experimental test and theoretical simplification methods.The results demonstrate close agreement among the three methods,with a maximum deviation is less than 8%,which indicates that the established method for calculating the bearing capacity of corroded components after reinforcement is reliable and can be used for the design calculation of corroded lining reinforcement.Finally,a restoration scheme is proposed for sections with a corrosion depth of engineering lining concrete less than or equal to 10 cm.The specific scheme is to chisel away the old concrete with a thickness of 10 cm on
作者
邱子乐
雷明锋
QIU Zile;LEI Mingfeng(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;School of Civil Engineering,Central South University,Changsha 410075,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2023年第6期2188-2197,共10页
Journal of Railway Science and Engineering
基金
广铁(集团)公司科技创新专项项目(2020K041-G)。
关键词
隧道工程
衬砌腐蚀
槽钢加固
室内构件试验
承载力计算
数值模拟
tunnel engineering
lining corrosion
channel reinforcement
indoor component test
bearing capacity calculation
numerical simulation
