Abstract:

 Due to the development and improvement of the shield tunneling technology, more and more Metro tunnels are constructed by shield tunneling method, which in most cases calls for the consolidation of the launching and arrival shafts. In cases where the launching and arrival shafts are consolidated by traditional methods, the retaining structures of the launching and arrival shafts should be dismantled by machinery in advance. If some new materials, such as Fiberreinforced Foamed Urethanes (FFU), are used to replace the traditional retaining structures within the crosssection of the shieldbored tunnels, however, the retaining materials can be cut directly by shield machines and the ground consolidation scope can be greatly reduced. On basis of the design of the launching shaft of South Datanshan～Zhongshan Eight Road shieldbored tunnel on line 5 of Guangzhou Metro, the authors present the application of Shield Earthretaining Wallsystem (SEW) construction method and FFU in shield launching construction.