STUDY OF PILE UPLIFT CHARACTERISTICS IN SWELLING CLAYS USING A NEWLY DEVELOPED TEST

Piles embedded in swelling clays are subject to uplift as these clays expand with increasing moisture contents. The magnitude of soil heave, pile heave and the uplift force developed on a pile depend on the initial and change in moisture content, the density and type of the clay, pile type, and the thickness of the clay layer. A new pile swell apparatus was designed to study the influence of these factors on piles in swelling clays. The apparatus is designed to vary the normal stress on the sample and has arrangements to measure either uplift force or pile displacements and soil heave across the surface of the sample. Pile swell tests for bentonite and chinle clay are performed. The soil sample size, apparatus edge effects, moisture and density effects and vertical stress effects are evaluated for different pile fixity conditions. The results show that at constant moisture content, swelling pressure on the pile increases exponentially, while soil heave increases linearly, with increasing density. As the normal stress on the sample is increased, soil heave decreases. However, swelling pressure on the pile increases sharply for small increases in the vertical stress, reaches a maximum value, and then decreases gradually. The soil heave decreases, but the uplift force on the pile increases as the pile movement is prevented. (Author/TRRL)

Media Info

  • Features: Figures; Photos; References;
  • Pagination: p. 75-79
  • Serial:
    • Issue Number: 84/3

Subject/Index Terms

Filing Info

  • Accession Number: 00389695
  • Record Type: Publication
  • Source Agency: ARRB
  • ISBN: 0-85825-219-8
  • Files: ITRD, TRIS, ATRI
  • Created Date: Mar 29 1985 12:00AM