Railway tunnel concrete lining damaged by formation of gypsum,thaumasite and sulfate crystallization products in southwest of China  

作　　者：马昆林 龙广成 谢友均 

机构地区：[1]School of Civil Engineering,Central South University [2]National Engineering Laboratory for Construction Technology of High Speed Railway [3]Department of Mechanical Engineering,Hunan Industry Polytechnic

出　　处：《Journal of Central South University》2012年第8期2340-2347,共8页中南大学学报（英文版）

基　　金：Project(51108463) supported by the National Natural Science Foundation of China;Project(11B041) supported by Scientific Research Fund of Hunan Provincial Education Department of China;Project(NCET-10-0839) supported by Ministry Education of China

摘　　要：The railway tunnel concrete lining exposed to sulfate-bearing groundwater beyond 40 years in southwest of China was investigated. Field investigation, sulfate ions content and corroded products analysis, macro/microscopic test were carried out. Results show that under the tunnel concrete lining structure and its served environmental conditions, sulfate solutions permeate concrete lining and accumulate on windward-side of concrete lining, resulting in the increase of sulfate ions content on windward-side and the diffusion of sulfate ions from windward-side to waterward-side, which cause the concrete lining of windward-side damaged seriously but the waterward-side of concrete lining is still in perfect condition. It is confirmed that structural characteristic of tunnel and environmental conditions lead to physical attack with the leaching of concrete and sodium sulfate crystallization as well as chemical corrosion with formation of gypsum in high sulfate concentration and formation of thaumasite in proper temperature rather than formation of ettringite. These achievements can provide academic and technical supports for understanding the deterioration mechanism of concrete lining as well as constructing railway tunnel under sulfate attack.The railway tunnel concrete lining exposed to sulfate-bearing groundwater beyond 40 years in southwest of China was investigated. Field investigation, sulfate ions content and corroded products analysis, macro/microscopic test were carried out. Results show that under the tunnel concrete lining structure and its served environmental conditions, sulfate solutions permeate concrete lining and accumulate on windward-side of concrete lining, resulting in the increase of sulfate ions content on windward-side and the diffusion of sulfate ions from windward-side to waterward-side, which cause the concrete lining of windward-side damaged seriously but the waterward-side of concrete lining is still in perfect condition. It is confirmed that structural characteristic of tunnel and environmental conditions lead to physical attack with the leaching of concrete and sodium sulfate crystallization as well as chemical corrosion with formation of gypsum in high sulfate concentration and formation of thaumasite in proper temperature rather than formation of ettringite. These achievements can provide academic and technical supports for understanding the deterioration mechanism of concrete lining as well as constructing railway tunnel under sulfate attack.

关 键 词：railway tunnel concrete lining sulfate attack deterioration mechanism 

分 类 号：U213.12[交通运输工程—道路与铁道工程]