TEMPERATURE EFFECT ON WATER RETENTION AND SWELLING PRESSURE OF CLAY SOILS

CLAY-WATER INTERACTION IN SOIL SYSTEMS WHERE SOLUTE EFFECTS ARE NEGLIGIBLE IS MEASURED BY THE MATRIC POTENTIAL. THE TWO FORCES CONTRIBUTING TO THE MATRIC POTENTIAL ARE THE SWELLING AND CAPILLARY FORCES. THEORETICAL EXPECTATION AND AVAILABLE EXPERIMENTAL EVIDENCE INDICATE THAT TEMPERATURE CHANGES INFLUENCE THE TWO COMPONENTS DIFFERENTLY. WHILE AN EXACT SEPARATION OF FORCES CANNOT BE MADE BECAUSE THEY MAY NOT NECESSARILY BE COMPLETELY INDEPENDENT, AN ASSESSMENT OF THE SPECIFIC CONTRIBUTION OF EACH CAN BE ATTEMPTED THROUGH CONTROLLED EXPERIMENTS. MEASUREMENTS WERE MADE AT 10, 25, AND 45 C OF SOIL SUCTION ON PLASTER OF PARIS SAMPLES WITH DIFFERENT VOID-SIZE DISTRIBUTION, AND OF SOIL SUCTION AND SWELLING PRESSURE ON KAOLINITE-GLASS BEAD MIXTURES. SOIL SUCTION WAS MEASURED ON THE ADSORPTION CYCLE. THE CLAY-GLASS BEAD SAMPLES WERE PRECOMPRESSED TO 10 BAR AND WERE THEN EITHER ALLOWED TO SWELL (REBOUND) UNDER DECREASING LOAD, OR WERE TRANSFERRED TO A PRESSURE PLATE APPARATUS AND ALLOWED TO TAKE UP WATER UNDER DECREASING AIR PRESSURE. THE RESULTS SHOW THAT IN THE SWELLING PRESSURE TESTS, WHERE COMPLETE SATURATION EXISTS, INCREASED TEMPERATURES RESULTED IN SLIGHTLY INCREASED WATER CONTENTS FOR THE SAME SWELLING PRESSURE. THIS IS CONSISTENT WITH QUALITATIVE PREDICTIONS BASED ON THE THEORY OF SWELLING DUE TO INTERACTION OF DIFFUSE ION-LAYERS. FOR SOIL SUCTION MEASUREMENTS, WHERE UNSATURATION OCCURS, INCREASED TEMPERATURES RESULTED IN DECREASED WATER CONTENTS FOR THE SAME SOIL WATER POTENTIAL. THIS WOULD RESULT FROM DECREASED VALUES OF SURFACE TENSION WITH THE TEMPERATURE INCREASES. THIS IS DEMONSTRATED MORE CLEARLY WITH THE PLASTER OF PARIS SAMPLES WHERE THE CAPILLARY FORCE IS THE ONLY COMPONENT OF MATRIC POTENTIAL. THESE MEASUREMENTS OF TEMPERATURE EFFECTS ARE MORE USEFUL BECAUSE BOTH SWELLING AND WATER UPTAKE ARE MEASURED ON IDENTICAL SAMPLES. THE VARIOUS AND SWELLING AS AFFECTED BY TEMPERATURE. /AUTHOR/

Media Info

  • Media Type: Print
  • Features: Figures; References;
  • Pagination: pp 132-137
  • Monograph Title: Effects of temperatures and heat on engineering behavior of soils
  • Serial:

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Filing Info

  • Accession Number: 00237760
  • Record Type: Publication
  • Files: TRIS, TRB, ATRI
  • Created Date: Aug 25 1994 12:00AM