EVALUATION OF LABORATORY TECHNIQUES FOR MEASUREMENT OF SWELL POTENTIAL OF CLAYS

IN EVALUATING THE HEAVY POTENTIAL OF A SOIL, IT IS DESIRABLE TO DO AS MUCH TESTING AS POSSIBLE IN THE LABORATORY, WHERE THE PARAMETERS THAT AFFECT SWELLING CAN BE CONTROLLED. A RESEARCH EFFORT ORIENTED TOWARD THE EVALUATION OF SOME NEWLY DEVELOPED TYPES OF LABORATORY APPARATUS, AND THE DEVELOPMENT OF TESTING TECHNIQUES TO ASSESS THE SWELL POTENTIAL ARISING FROM SOME OF THE DIFFERENT SOURCES OF SWELLING IS CURRENTLY BEING CONDUCTED BY THE OFFICE OF RESEARCH OF THE FEDERAL HIGHWAY ADMINISTRATION. THE STUDY HAS FOUR PRINCIPAL GOALS: (1) EVALUATION OF THE OSMOTIC CELL-CONSOLIDOMETER APPARTUS AS A DEVICE FOR CONTROLLING SOIL SUCTION; (2) DEVELOPMENT OF TECHNIQUES TO EXPEDITE LABORATORY EXAMINATION OF THE INFLUENCE OF SUCTION ON THE HEAVE POTENTIAL OF SOILS; (3) DEVELOPMENT OF TECHNIQUES TO ESTIMATE THE HEAVE POTENTIAL OF WELL-BONDED, OVERCONSOLIDATED PLASTIC SOILS, SUBJECTED TO STRESS RELEASE; AND (4) ASSESSMENT OF THE INFLUENCE OF CYCLIC DRYING AND WETTING ON THE HEAVE POTENTIAL. THESE GOALS ARE DISCUSSED IN THIS REPORT AND THE FOLLOWING CONCLUSIONS ARE REACHED: (1) THE OSMOTIC CELL-CONSOLIDOMETER APPARATUS HAS THE POTENTIAL O BEING A USEFUL APPARATUS FOR LABORATORY INVESTIGATIONS OF THE INFLUENCE OF THE STATE OF SUCTION ON ONE DIMENSIONAL SWELLING. THE APPARATUS IS SIMPLE AND INEXPENSIVE. THE TECHNIQUE, HOWEVER, MAY REQUIRE UNDULY LONG EQUILIBRATON PERIODS, ESPECIALLY AT HIGHER SUCTION LEVEL. (2) IT HAS BEEN REPORTED THAT POOR CONTACT BETWEEN A SOIL SPECIMEN AND THE SEMIPERMEABLE MEMBRANE IN THE OSMOTIC CELL DEVICE, OR BETWEEN A SOIL SPECIMEN AND THE CERAMIC PLATE IN THE PRESSURE PLATE DEVICE, RESULTS IN LONG EQUILIBRATION PERIODS. IT MAY BE POSSIBLE TO REDUCE THIS TESTING TIME FOR SOME COMBINATIONS OF CHANGES IN LOADING AND SUCTION. (3) THE TIME-DEPENDENT HEAVING OF OVERCONSOLIDATED WELL-BONDED PLASTIC CLAY-SHALES INVOLVES A NUMBER OF INTERDEPENDENT PHENOMENA. BOTH SHEAR AND TENSILE STRESSES MAY BE IMPORTANT CONTRIBUTORS TO THE HEAVING OF SUCH CLAY-SHALES. THERE IS A NEED FOR TECHNIQUES THAT CAN BE USED TO PREDICT THE LONG TERM HEAVE POTENTIAL THAT ARISES FROM STRESS RELEASE DURING THE EXCAVATION OF CLAY-SHALES. (4) DRYING AND WETTING CAN BE AN IMPORTANT CONTRIBUTOR TO THE SWELLING POTENTIAL OF PLASTIC SOILS HAVING EITHER WEAK OR WELL-DEVELOPED DIAGENTIC BONDS. THERE MAY BE FIELD SITUATIONS WHERE DRYING AND WETTING IS RESPONSIBLE FOR SIGNIFICANT HEAVING OF PAVEMENTS FOUNDED OVER SUCH SOILS.

  • Supplemental Notes:
    • Proceedings, Workshop on Expansive Clays and Shales in Highway Design and Construction, Denver, Colorado, 1972. Available in 2 volumes from NTIS, PB-225842.
  • Corporate Authors:

    University of Wyoming, Laramie

    Wyoming Survey and Analysis Center, 710 Garfield
    Laramie, WY  USA  82070

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  USA  20590
  • Authors:
    • Obermeier, S F
  • Publication Date: 1973-5

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Filing Info

  • Accession Number: 00230353
  • Record Type: Publication
  • Report/Paper Numbers: Workshop Proceedings
  • Files: TRIS, USDOT
  • Created Date: Jul 31 1974 12:00AM