ELECTRICAL RESISTIVITY TECHNIQUES

A LABORATORY STUDY DETERMINED THAT THE BPR INSTRUMENT IS NOT ALWAYS ACCURATE AND HAS LIMITED APPLICATION. THE BISON AND GEO-RECON INSTRUMENTS PROVIDED ACCURATE READINGS OVER A MUCH WIDER RANGE OF CONDITIONS. FIELD TESTING DID NOT INDICATE ANY SIGNIFICANT DIFFERENCE EXISTED BETWEEN THE RESULTS OBTAINED BY THE AC FROM THE BISON AND THE DC FROM THE GEO-RECON OR BPR INSTRUMENTS. FIXED DEPTH SURVEYS WERE RUN USING DIFFERENT PROFILING ARRAYS. THE 3-ELECTRODE WENNER ARRAY PROFILES DID NOT PRODUCE USEFUL DATA FROM THE DEPTH OF INTEREST. THE GRADIENT ARRAY WAS THE FASTEST AND COULD QUICKLY LOCATE HORIZONTAL ANOMALIES. THE 4-ELECTRODE WENNER ARRAY GAVE GOOD DEPTH DEFINITION AND APPEARS TO GIVE A GREATER AMPLITUDE OF RESPONSE TO HORIZONTAL CHANGE. TEST LINES RUN WITH THE BISON INDICATE READINGS FROM WET AND DRY ELECTRODES WITH AND WITHOUT BALANCING SHOULD NOT BE MIXED IN THE SAME PROFILE OR EXPANDING SPREAD. THE STANDARD EQUIPMENT BISON REELS AND STAKES PROVED UNSATISFACTORY AND WERE REPLACED WITH THE REELS AND STAKES THAT CAME WITH THE GEO-RECON. FIXED DEPTH TRAVERSES WERE SUCCESSFULLY INTERPRETED BY MEANS OF PROFILES AND BY CONTOURING, BUT THE CONTOURS PRESENTED A MORE COMPLETE PICTURE. THE VERTICAL ELECTRICAL SOUNDINGS WERE INTERPRETED BY EMPIRICAL MEANS AND BY THE CURVE MATCHING TECHNIQUE. THE CURVE MATCHING TECHNIQUE SEEMED TO BE MORE CONSISTENT WITH KNOWN FACTS. /FHWA/

  • Supplemental Notes:
    • Contract F-7-71
  • Corporate Authors:

    California Department of Transportation

    Transportation Laboratory
    5900 Folsom Boulevard
    Sacramento, CA  United States  95819
  • Authors:
    • Stephens, E
  • Publication Date: 0

Media Info

  • Pagination: 83 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00228703
  • Record Type: Publication
  • Source Agency: California Department of Transportation
  • Report/Paper Numbers: Final Rept
  • Files: TRIS, STATEDOT
  • Created Date: Jun 19 1974 12:00AM