Rock cutting with a tunnel boring machine (tbm) involves the indentation of a rock surface by cutting tools, which are mounted in an array on the front of a cutterhead. A simplistic view of a tbm would be that of a machine which generates thrust to push the cutterhead forward and supplies torque to turn the cutterhead against the tangential forces resisting cutting tool motion and indentation. This note describes the nature of rock-tool interaction during cutting indentation. Parameters to describe tbm performance are defined, and the importance of using case history studies to identify optimum tbm performance is discussed. Rock comminution effected by a tbm is accomplished by the propagation of fractures which release rock chips. This fracture mechanism suggests that excavation efficiency should be linked to fracture material properties. The results of a preliminary investigation into the correlation between intact rock fracture properties and the performance of tbms involved in actual construction projects are given. (TRRL)

  • Availability:
  • Corporate Authors:

    Pergamon Press, Incorporated

    Headington Hill Hall
    Oxford OX30BW,    
  • Authors:
    • Nelson, P P
    • Ingraffea, A R
    • O'ROURKE, T D
  • Publication Date: 1985-6

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00451320
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: May 31 1986 12:00AM