MECHANISMS OF SWELLING BY COMPACTED CLAY

THE MECHANISMS BELIEVED TO CAUSE SWELLING IN SATURATED CLAY-WATER SYSTEMS ARE FIRST REVIEWED. THESE CONCEPTS, DRAWN PRIMARILY FROM SOIL CHEMISTRY AND SOIL PHYSICS, ARE EXTENDED TO COMPACTED NATURAL CLAYS. TEST DATA ARE PRESENTED TO SHOW THE EFFECTS OF THE ION CONCENTRATION IN THE PORE FLUID ON THE SWELLING BEHAVIOR OF A HIGHLY PLASTIC CLAY. THESE DATA CONSIST PRIMARILY OF HEAVING AND FLUID PICKUP MEASUREMENTS ON SAMPLES MOLDED WITH PURE WATER AND SOAKED IN SOLUTIONS OF VARYING SALT CONCENTRATIONS. FOR THE CLAY INVESTIGATED, IT IS CONCLUDED THAT (1) FOR SAMPLES COMPACTED WET OF OPTIMUM WATER CONTENT, SWELLING CAN BE EXPLAINED BY OSMOTIC REPULSIVE PRESSURES ARISING FROM THE DIFFERENCE IN ION CONCENTRATION IN THE DOUBLELAYER WATER BETWEEN INTERACTING CLAY PARTICLES AND THAT IN THE FREE PORE WATER, AND (2) FOR SAMPLES COMPACTED DRY OF OPTIMUM WATER CONTENT, SWELLING IS INFLUENCED BY FACTORS IN ADDITIONS TO OSMOTIC PRESSURES. THESE OTHER FACTORS MAY BE THE EFFECT OF THE NEGATIVE ELECTRIC AND LONDON VAN DER WAALS FORCE FIELDS ON WATER, CATION HYDRATION AND THE ATTRACTION OF THE PARTICLE SURFACE FOR WATER, ELASTIC REBOUND OF PARTICLES, A FLOCCULATED PARTICLE ORIENTATION, AND THE PRESENCE OF AIR. THE RELATIVE IMPORTANCE OF THESE OTHER FACTORS IS NOT KNOWN. /AUTHOR/

Language

  • English

Media Info

  • Monograph Title: Water tensions: swelling mechanisms: strength of compacted soil
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00232448
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Aug 15 2004 2:43AM