人工冻结技术在上海地铁施工中的应用

Application of the Artificially Ground Freezing Method to Shanghai Metro Engineering

对人工冻结工程中的监测采集数据进行了全面分析.结果表明:人工冻结法施工中冻结区的温差较大边界和刚性约束边界对冻结法施工影响明显.温差较大边界是冻土帷幕强度和止水作用的薄弱环节,而刚性约束边界距离人工冻结区越近冻土的冻胀力越大;同时也表明在一定的工程地质条件下,通过合理选取盐水冻结系统所采用的各项指标、降温梯度及其设置冻胀吸收孔,能够将冻结产生的冻胀力与冻胀量控制在周围环境的容许范围内.

The paper discusses the technology of the artificially ground freezing and analyzes the data gathered in the process of making artificially frozen walls. The boundary with greater temperature difference in frozen soil and the rigid boundary of the frozen wall have important impact on the artificially frozen wall. The strength of frozen wall near the boundary of greater temperature difference is obviously poor. The higher the temperature of the boundary of frozen wall is, the lower the strength of frozen wall is. So the area of the high temperature difference has a great affect on the underground construction. The distance between the rigid boundary and the frozen wall apparently influences the frost-heaving force. The shorter the distance is, the greater the frost-heaving force is.The study shows that selecting some proper parameters of the freezing system and designing some holes for frostheaving release can control the frost-heaving force and the amount of frost heaving.