DRILLING OF VENTILATION AND SERVICE SHAFTS IN TUNNELLING

THE VENTILATION OF A TUNNEL BY MEANS OF VENTILATION PIPING CARRIED IN THE TUNNEL AND TO SURFACE THROUGH THE MAIN SHAFT SYSTEMS IS CONSIDERED AND THIS TYPE OF INSTALLATION IS COMPARED WITH ONE IN WHICH SMALLER DIAMETER SHAFTS ARE DRILLED ALONG THE TUNNEL LINE TO PROVIDE UPCAST VENTILATION AT POSITIONS OTHER THAN THE MAIN SHAFT POSITIONS.THE TYPE OF DRILLING RIG USED FOR THIS WORK IS DESCRIBED WITH EMPHASIS ON THE USE OF THE REVERSE CIRCULATION FLUSHING SYSTEM FOR HOLES OF A SIZE SUITABLE FOR SHAFTS OF THIS NATURE AND THE PROCEDURE ADOPTED IN DRILLING LARGE HOLES IS OUTLINED BRIEFLY. COSTS ARE CALCULATED FOR A TUNNEL WITH THREE MAIN SHAFTS WHEN ALL THE VENTILATION AIR IS EXHAUSTED TO SURFACE THROUGH THE SHAFTS, AND THESE COSTS ARE ARE COMPARED WITH THOSE FOR THE SAME TUNNEL WHEN 36-IN. DIAMETER VENTILATION SHAFTS ARE DRILLED AT SELECTED POINTS ALONG THE TUNNEL LINE. THE SAVING IN THE COST OF PIPING AND THE REDUCTION IN POWER REQUIREMENTS INDICATES THAT IN SUITABLE FORMATIONS AND WHERE THE DEPTH OF THE BOREHOLES IS LESS THAN 1,000 FT, THE USE OF DRILLED BOREHOLES FOR UPCAST VENTILATION SHAFTS IS AN ATTRACTIVE ECONOMIC PROPOSITION. /RRL(A)/

  • Authors:
    • Middleton, J V
  • Publication Date: 1970-6

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00235168
  • Record Type: Publication
  • Source Agency: Road Research Laboratory /UK
  • Report/Paper Numbers: pp 197-201
  • Files: TRIS
  • Created Date: Aug 29 1971 12:00AM