In a discussion of rock tunnel construction by drill and blast methods, the merits of vee cuts and parallel cuts are examined. A parallel blast hole cut technique is proposed which is based on fracture plane control. Three blast holes at equi-angular spacing are notched and then fired with a cushioned charge to produce six controlled fracture planes which isolate a hexagonal region. A fourth hole, heavily charged and located in the centre of the hexagonal region, is fired to fracture this area and to eject the fragments from the rock face. It is suggested that the hexagonal cuts will offer savings in drilling time and costs. /TRRL/

  • Availability:
  • Corporate Authors:

    Morgan-Grampian Limited

    30 Calderwood Street
    London SE18 6QH,   England 
  • Authors:
    • Barker, D B
    • Fourney, W L
    • Dally, J W
  • Publication Date: 1978-5

Media Info

  • Features: Figures; References;
  • Pagination: p. 29-33
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00182780
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Nov 14 1978 12:00AM