Horizontal ground freezing method applied to tunneling of Beijing Underground Railway System

During the construction of the south railway tunnel in DaRe Area of Beijing Underground Railway System, there was a water saturated layer of fine sand on the roof of the tunnel area. The tunnel area is located under the Guomao Overpass and there are several underground pipelines located in the tunnel area. To assure a normal operation and safety of the pipelines and overpass , horizontal ground freezing method was applied to the tunneling for the first time in China. This paper has stated the design, the key technologies and the practical results of this method, and discussed the technical tendency in combination of the ground freezing and the excavation with a shallow depth.