化学腐蚀环境下盾构隧道管片防腐研究

Study on Silane Impregnation Design of Shield Segment under Chemical Corrosive Environment

为了解决化学腐蚀环境下盾构隧道管片耐久性防腐问题,文章依托衡阳市二环路合江套湘江隧道工程实例开展了系统性的设计研究。结合化学腐蚀环境下结构腐蚀机理,为确保本工程设计使用年限内管片结构的安全性和可靠性,从结构、材料配合比以及防腐涂料等方面对管片耐久性防腐设计进行了明确,通过比选,选择三甲基戊基三乙氧基硅烷材料作为本工程管片的防腐涂料;从硅烷浸渍深度、吸水率以及氯化物吸收量三方面针对不同的喷涂工艺以及不同的硅烷喷涂料量开展了硅烷浸渍涂料现场工艺试验,分析得出俯喷工艺较仰喷以及站喷工艺在效果和成本方面具有明显优势,建议采用俯喷工艺对内弧面和外弧面进行喷涂,最佳喷涂量为400 g/m^2,管片端侧面可采用站喷工艺进行喷涂,最佳喷涂量为500 g/m^2。

In order to solve the problems of durability and anti-corrosion of shield segment under chemical corro⁃sive environment,a study of systematic design is carried out based on the Xiangjiang tunnel in Hengyang city.In light of the structural corrosion mechanism and guaranteeing of safety and reliability of segment structure within the design service life under chemical corrosive environment,the corrosion resistance design of segment durability is de⁃termined in terms of structure,material mix ratio,anti-corrosive paint and so on,and trimethyl amyl triethoxy silane is selected as an anticorrosive coating after a comparison;field process test of silane impregnated coating is carried out from aspects of silane impregnation depth,water absorption and chloride absorption for different spraying tech⁃nologies and spraying amounts of silane coatings,and it is concluded that the downward spraying process has obvious advantages over the upward and horizontal spraying process in terms of effect and cost,it is suggested the downward spraying process is used to spray the inner and outer arc surfaces and the optimum spray quantity is 400 g/m^2,horizon⁃tal spraying can be adopted for the end and side face of the segment and the optimum spray quantity is 500 g/m^2.