A method of soil strain measurement is described, which is based on the use of a sensor consisting of a pair of small flat coil discs. The discs are embedded in the soil without any physical connection between the coils so as not to constrain soil movement in the region of the sensor, and changes in the spacing of the coils are recorded as differential voltages, which can be read on a meter, an oscilloscope or a chart recorder. Both static and dynamic deformations or strains can be measured with the instrument, though a separate instrument has been developed for each case. The resolution is at least 0.01% strain, and changes as fast as 0.125 MSEC can be recorded on the dynamic instrument. The signal noise ratio is satisfactory for large strains but is too small at strains of approximately 0.005%. The use of the dynamic apparatus in asphaltic concrete is described. /TRRL/

  • Corporate Authors:

    National Roads Board, New Zealand

    Road Research Unit
    Wellington,   New Zealand 
  • Authors:
    • Paterson, WDO
  • Publication Date: 1972

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: 30 p.
  • Serial:
    • Issue Number: 13

Subject/Index Terms

Filing Info

  • Accession Number: 00291154
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: R&D Rept.
  • Files: ITRD, TRIS
  • Created Date: Sep 19 1974 12:00AM