Tunnel construction is an uncertain and sometimes hazardous undertaking because information on ground conditions along the alignment is never complete, no matter how good the site investigation. There is a strong need, therefore, for the development of reliable methods of determining ground conditions ahead of the advancing tunnel face, whilst recognizing that such methods should not interfere too much with the tunnelling operations. The working party on probing ahead for tunnels was set up to review the present state of knowledge and to make recommendations for research and development on promising methods. This report presents the findings. The methods available are long horizontal boreholes drilled between shafts, direct drilling from the tunnel face, geophysical measurements made at the tunnel face or on the surface or from a borehole drilled from the tunnel face and, in certain circumstances, the driving of A pilot tunnel. The principal recommendations are that encouragement should be given in the short term to collecting information and publishing details of existing practice in probing ahead, and in the medium term to the development of horizontal drilling methods for use either from shafts or at the tunnel face and to research into the feasibility of geophysical methods used either at the tunnel face or in a horizontal borehole. In the long term, encouragement should be given to a systems approach in which a horizontal drill would be fully incorporated into the tunnelling machine and a geophysical method could be operated in the probe hole. (A) /TRRL/

  • Corporate Authors:

    Transport and Road Research Laboratory (TRRL)

    Wokingham, Berkshire  United Kingdom 
  • Publication Date: 1975

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 49 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00132884
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: No. SR171UC R&D Rpt.
  • Files: ITRD, TRIS, ATRI
  • Created Date: Jul 13 1976 12:00AM