Abstract:

In order to solve a series of urban development problems such as city overcrowding and traffic congestion, engineers have carried out researches on how to develop and utilize underground space better and proposed the piperoofing method with various section types. As a new underground excavation method, this method is used widely owing to its less influence on surrounding environment and controllable ground subsidence. Nevertheless, due to the high water content, high compressibility and weak self-stabilizing ability of saturated soft soil, there are few engineering cases using the pipe-roofing method in the above areas. Consequently, based on the project of Guiqiao Road station of Shanghai metro line 14, and in consideration of the characteristics of saturated soft soil, the technologies of the pipe-roofing method including pipe jacking, soil reinforcement and layered excavation inside the pipe-roof are researched. The results show that the key technologies mentioned above can ensure the sealing and connection of the pipe lock, improve the strength of the excavated soil and reduce the influence of construction on the surrounding environment.

Key words: free section, pipe-roofing method, underground structure, saturated soft soil, pipe jacking, soil reinforcement, layered soil excavation