An investigation has been made into the reproducibility of measurement of joint frequency and orientation in the lower chalk. The opportunity was also taken to compare measurement of joint frequency made from stereophotographs with measurement made on site. It was found that measurement of joint spacing was a subjective matter, the joint distribution diagrams being different for different observers. However, measurements from stereophotographs showed no more variation than site measurements. It was found that both the dip angle and dip direction could be determined to about plus or minus 6 degrees for well-defined joints, but that different observers produced joint orientation diagrams which differed in detail, although agreeing in broad outline. The work has important implications for tunnelling - at site investigation stage, during tunnel monitoring and in the course of tunnelling research. In particular, joint spacing measurements made by different observers may vary by up to a factor of 2 without there being any real difference in the joint spacing of the rock. (a) (TRRL)

  • Availability:
  • Corporate Authors:

    Transport and Road Research Laboratory (TRRL)

    Wokingham, Berkshire  United Kingdom 
  • Authors:
    • WEST, G
  • Publication Date: 1979

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Filing Info

  • Accession Number: 00310453
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Report/Paper Numbers: TRRL SR 488 Monograph
  • Files: ITRD, TRIS, ATRI
  • Created Date: Jun 26 1980 12:00AM