Application of Freezing Method in Construction of Connection Galleries of Metro Works in Intensely-disturbed Ground

The key points of the freezing in the construction of the connection gallery of the running tunnel from Nanpu Station to Luoxi Station on the extended section of No.2 and No.8 line of Guangzhou Metro,such as pre-freezing preparation,excavation and settlement control,are presented.The brine water temperatures,the frozen soil temperatures,the pressures in the pressure-releasing boreholes and the frost-heaving pressures are monitored.The variation rules of the brine water temperatures,the frozen soil temperatures,the pressures in the pressure-releasing boreholes and the frost-heaving pressures are obtained by means of analysis on the monitoring results and advices are made on the construction of the connection gallery.Comparison and contrast are made between this project and other conventional freezing projects and the differences in terms of the pressures in the pressure-releasing boreholes,the frost-heaving pressure and the deformation induced by the frost-heaving and thaw settlement are described.The successful experience achieved in the project can provide reference for similar projects in the future.