LARGE IN-SITU TESTS TO MEASURE THE PROPERTIES OF STIFF FISSURED CLAYS

IN-SITU TESTS WERE CONDUCTED USING DIFFERENT SIZES AND TYPES OF EQUIPMENT IN CONJUNCTION WITH LABORATORY TESTS ON SPECIMENS OF VARIOUS SIZES PREPARED AND SAMPLED BY THE BEST AVAILABLE TECHNIQUES. LOADING TESTS ON AN 865 MM DIAMETER PLATE INSTALLED AT VARIOUS LEVELS IN BOREHOLES, AND IN-SITU SHEAR TESTS USING A 610 MM SQUARE SHEAR BOX FORMED AN IMPORTANT PART OF THE INVESTIGATIONS. FACTORS WHICH MAY AFFECT THE UNDRAINED PROPERTIES OF STIFF FISSURED CLAY ESTIMATED FROM IN-SITU LOADING TESTS ARE DISCUSSED. RESULTS INDICATE THE IMPORTANCE OF THE INFLUENCE OF FISSURES ON THE PROPERTIES OF FISSURED CLAYS, ELUCIDATE THE BEHAVIOR OF CLAYS, AND PROVIDE STRENGTH AND DEFORMATION PARAMETERS MORE APPLICABLE TO ENGINEERING DESIGN THAN THOSE MEASURED IN LABORATORY TESTS ON 'UNDISTURBED' SAMPLES. COMPARISON OF THE REULTS OF LARGE IN-SITU PLATE TESTS WITH LABORATORY TESTS HAVE SHOWN THAT EVEN IN THE SAME TYPE OF CLAY THE RELATIONSHIPS BETWEEN VARIOUS TESTS VARY WITH DEPTH, LOCATION, AND DIFFERENCES IN THE FISSURE STRUCTURE. THE SAME CONCLUSIONS APPLY TO SMALL IN-SITU TESTS. TO OBTAIN REPRODUCIBLE AND RELIABLE ESTIMATES OF THE MODULI OF STIFF FISSURED CLAYS IT IS NECESSARY TO MAKE LOADING TESTS IN BOREHOLES WHICH ARE SUFFICIENTLY LARGE TO ENABLE A MAN TO REMOVE LOOSENED CLAY FROM THE TEST LEVEL. PROBLEMS WILL BE ENCOUNTERED IN THE APPLICATION OF THE METHODS DESCRIBED TO HARDER CLAYS. THE NEED FOR FURTHER INVESTIGATION OF THE EFFECTS OF DRILLING BOREHOLES AND THE INTERVAL OF TIME BETWEEN EXCAVATION AND TESTING IS INDICATED.

  • Corporate Authors:

    Building Research Establishment

    Bucknalls Lane, Gorston
    Watford WD2 7JR, Hertfordshire,   England 
  • Authors:
    • Marsland, A
  • Publication Date: 1973-1

Media Info

  • Features: Figures; References;
  • Pagination: 12 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00236611
  • Record Type: Publication
  • Report/Paper Numbers: No Cp 1/73
  • Files: TRIS
  • Created Date: Sep 17 1973 12:00AM