UNDERCUTTING - A UNIQUE METHOD TO BORE NON-CIRCULAR OPENINGS

IN THIS METHOD, THE CUTTERHEADS ARE MOUNTED ON THE BORING HEAD AT A SLIGHT ANGLE TO THE TUNNEL AXIS AND THE ADVANCING OF THE BORING HEAD WITH A SPEED RELATED EXACTLY TO ITS ROTATION, MAKES IT POSSIBLE TO LET THE CUTTER TIPS (EACH OF WHICH HAVE A PLANETARY MOVEMENT AROUND THE MECHINE AXIS) PENETRATE THE ROCK IN CONCENTRIC, HELICAL PATHS, CUTTING THE TUNNEL LIKE A MUTIPLE-START INTERNAL THREAD. THE FACE IS CUT RADIALLY AND THE CUTTER HEADS TRAVERSE IN A SCREW LINE, SO MAKING IT POSSIBLE TO "UNDERCUT" THE ROCK, I.E. THE CUTTER TIPS ACT AT SOME DEPTH BELOW THE FACE AT ALL TIMES. THE ADVANTAGES OF THIS METHOD ARE ELABORATED. THE ORGANIZATION OF THE BORING OPERATIONS AND THE PERFORMANCE OF THE MACHINE IN A TUNNEL PROJECT IN SWITZERLAND IS DESCRIBED. DETAILS ARE GIVEN OF THE "MINI FULL FACER" WHICH ALLOWED A TUNNEL TO BE BORED WITH A WIDTH OF 4 FT. 3 IN. AND A HEIGHT OF 7 FT. 4 IN. IN THE CENTER. THE USE OF THE UNDERCUTTING METHOD IN MINING IS REVIEWED.

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 1197-23
  • Serial:
    • Volume: 2

Subject/Index Terms

Filing Info

  • Accession Number: 00236586
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 27 1974 12:00AM