地铁盾构管片渗水部位泛白现象的试验研究

Study of a Phenomena that White Substance Produced on the Surface of Shield Segment in Metro near the Position of Its Seepage

依托某在建地铁工程,通过对管片混凝土、盾构注浆、地下水质、泛白物等进行试验检测和研究,并结合同批次管片拼装后的实际情况,分析了管片渗水处泛白的原因。结果表明,管片渗水部位的泛白是盾构注浆浆体中的Ca(OH)2随渗水水流进入管片,在管片表面与空气中的CO2发生化学反应,产生白色的碳酸钙,而不是管片混凝土自身的泛碱。

The reason of producing white substance were analyzed, testings of the concrete for segment、grouting slurry for shield、quality of underground water and the white substance, and the actual situation of the same batch of shield segment that already installed. The results show that the white substance produced on the surface of shield segment near the position of its seepage is white calcium carbonate, which produced by calcium hydroxide transferring to the surface of shield segment by water from grouting slurry, and carbon dioxide from air, but not crystalline bloom of concrete shield segment.