Two types of slurry tunnelling machines are described both of which have been used on the Cairo wastewater project. The bade and theelen design (a slurry earth pressure balance machine) has 50% of the boring head in contact with the earth face and relies on the slurry pressure to balance earth and groundwater pressure. The okumura design (a mechanical earth pressure balance machine) has 85% of the head in contact, only the groundwater pressure being balanced by slurry pressure. The mechanism of the pumping system is described and differences noted in the slurry required by each type. Specifications for slurry and pumping systems used in the Cairo project are tabulated. The need for a flexible design is stressed which can cope with varying face conditions and changes in the slurry. Variations in the condition of the slurry and the concentration of spoil are described. The use of compressed air in slurry earth pressure balance machines is found to give them an advantage in some situations. The use of variable speed pumps to control slurry movements is examined and a circuit diagram provided by way of explanation. (TRRL)

  • Availability:
  • Corporate Authors:

    Mining Journal Limited

    60 Worship Street
    London EC2A 2HD,   England 


    London,   United Kingdom 
  • Authors:
    • -
  • Publication Date: 1988-12


  • English

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Filing Info

  • Accession Number: 00499382
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Sep 30 1990 12:00AM