Laboratory and underground trials of geophysical and television logging in a horizontal borehole have been made with the object of assessing their potentiality for use in probing ahead of tunnels. The commercially-available geophysical logging methods tested were gamma-gamma (long and short spacing), natural gamma, neutron-neutron, neutron-gamma, self-potential and resistivity; in addition a commercially-available borehole television camera was tested and a new ultrasonic velocity logger was designed and used. It was concluded that: (1) of the commercially-available geophysical logging methods, only the gamma-gamma method would seem to be useful in probing ahead of tunnels: it provided a good overall measure of density; (2) the borehole television camera was most successful in showing the presence of joints, cavities and other features; and (3) the prototype ultrasonic velocity logger provided a general indication of rock strength and could readily be developed for use in routine probing ahead.(a) (TRRL)

  • Corporate Authors:

    Transport and Road Research Laboratory (TRRL)

    Wokingham, Berkshire  United Kingdom 
  • Authors:
    • WEST, G
  • Publication Date: 1980

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: 39 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00319695
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Report/Paper Numbers: TRRL LR932 Monograph
  • Files: ITRD, TRIS, ATRI
  • Created Date: Feb 6 1981 12:00AM