Many difficulties associated with tunneling work in urban areas concern compliance with environmental regulations, as well as construction safety. Since much tunnel work in urban areas in Japan must be performed in soft alluvium ground with a high groundwater level, there has been a great demand for an environmentally acceptable soft ground tunneling method. A new technique is the earth pressure balanced shield (epbs) method, which consists of two types - earth pressure and water pressure. In this method, soil excavated by a rotating cutter frame is continuously removed in a controlled manner through a pressure soil chamber and an attached screw conveyor or auger. The attachment of a water pressure chamber at the end of the screw conveyor enables the system to excavate unstable and permeable sandy soil with high water pressure. Employing a newly developed synchronized grouting method, the tail void behind the shield structure is immediately filled with a pressurized high-density grout material. This clean and compact system offers minimum environmental impact, applicability to a wide variety of soil conditions, and minimal requirements for auxiliary supporting techniques for soil stabilization, such as dewatering and chemical grouting. This paper describes the main features of the water pressure type, with reference to some of the projects in which it was applied.(a) (TRRL)

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  • Corporate Authors:

    Pergamon Press, Incorporated

    Maxwell House, Fairview Park
    Elmsford, NY  United States  10523
  • Authors:
    • Ishihara, K
  • Publication Date: 1979-9-10

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Filing Info

  • Accession Number: 00308884
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Jun 9 1980 12:00AM