摘要
我国服役超过40年的老旧铁路隧道有4000余座,这些老旧隧道在各类腐蚀性物质及环境温度和湿度等因素联合作用下,极易产生腐蚀劣化问题,进而影响隧道的运营安全和服役寿命。依托HTG隧道工程,通过现场病害调研和取样检测等手段,探明隧道衬砌病害的分布特征和成因机理。研究表明:(1)HTG隧道主要病害形式为硫酸盐侵蚀导致的混凝土腐蚀劣化(实测强度值仅17~24 MPa,远低于设计强度)、衬砌开裂、表面渗漏水和盐结晶;(2)造成上述病害的主要原因有:(1)隧道处于富水硫酸盐的服役环境中,实测SO^(2)_(4)浓度达到619 mg/L,大量腐蚀性介质通过混凝土内部孔隙侵蚀混凝土,造成胶凝材料的流失和内部孔隙增多;(2)隧道内部湿度和温度随季节变化较大,加之运营过程中风速变化等因素,导致侵蚀性介质在混凝土内部快速传输;(3)隧道存在初始质量缺陷,施工时未采用抗SO^(2)_(4)侵蚀混凝土且混凝土的级配不合理;(4)隧道排水孔出现堵塞,防排水设施的局部失效,进一步加剧了硫酸盐对隧道衬砌腐蚀。
Currently,over 4000 old railway tunnels have been in service for more than 40 years.Under the coupling effect of all kinds of corrosive substances,environmental temperature and humidity,and other factors,these old tunnels are incredibly prone to corrosion deterioration problems,affecting the operation safety and service life of tunnels.Based on the HTG tunnel project,this paper explored the distribution characteristics and caused mechanism of tunnel lining defects using on-site investigation and indoor sampling test.The research results show that:(1)the main defect forms of HTG tunnel are concrete corrosion deterioration caused by sulfate erosion(the measured strength value is only 17~24 MPa,far lower than the design strength),lining cracking,surface leakage and salt crystallization;(2)The leading causes of the above defects are as follows:a)The tunnel is in the service environment with rich sulfate in water,and the measured sulfate concentration reaches 619 mg/L.A large number of corrosive media erode the concrete through the pores inside the concrete,resulting in the loss of cementing materials and the increase of internal pores;b)The humidity and temperature in the tunnel vary significantly with the season,all these factors and the change of wind speed in the operation process lead to the rapid transmission of corrosive medium in the concrete;c)There are initial quality defects in the tunnel construction,such as not using sulfate resistant concrete and unreasonable gradation of concrete;d)The tunnel drainage hole is blocked,and the partial failure of waterproof and drainage facilities further aggravates the corrosion of tunnel lining by sulfate.
作者
段炼
李永恒
伍江航
雷明锋
DUAN Lian;LI Yongheng;WU Jianghang;LEI Mingfeng(Zhangjiajie Works Section,China Railway Guangzhou Bureau Group Co.,Ltd.,Zhangjiajie 427000;School of Civil Engineering,Central South University,Changsha 410075)
出处
《现代隧道技术》
CSCD
北大核心
2022年第S01期727-734,共8页
Modern Tunnelling Technology
基金
广铁(集团)公司科技创新专项项目(2020K041-G)
关键词
铁路隧道
病害调查
硫酸盐侵蚀
成因机理
Railway tunnel
Defect investigation
Sulfate erosion
Cause analysis
