Abstract:

The difficulties in shield boring through complex sandy cobble ground with high permeability and high water pressure, including stability control of excavation face, filter membrane forming, wearing of cutter head and cutting tools and replacing of cutting tools under hyperbaric conditions, are analyzed. As a result, the topics to be studied, such as filter membrane forming in ground with high permeability, filter membrane forming mechanisms, stability of filter membrane and air tightness under hyperbaric conditions and cutting tool replacing under hyperbaric conditions, are presented. The paper can provide reference for the construction of extralong rivercrossing tunnels under high water pressure.

Key words: Yangtze Rivercrossing tunnel, slurry shield, high water pressure, sandy cobble strata, excavation face, stability, filter membrane, cutting tool, wearing, cutter replacing under hyperbaric condition