PREDICTING POTENTIAL HEAVE AND HEAVE WITH TIME IN SWELLING FOUNDATION SOILS

This study evaluates procedures for predicting one-dimensional potential heave of foundation soils and the rate at which heave may occur. A computer program ULTRAT (Ultimate and rate of heave) was developed for predictions of potential heave and heave with time based on two models for characterization of swell behavior: the soil suction and mechanical swell models. The soil suction model relates volume change with change in matrix soil suction and water content. Time rate of heave may be predicted from numerical solutions of a simplified advanced diffusion flow equation. The mechanical swell model uses results from swell tests performed in the consolidometer. Laboratory tests were performed to provide data for characterization of swell behavior using the models in the program ULTRAT. Testing procedures for the soil suction model are simple, economical, and expedient. The data are also useful for soils with any degree of saturation and the effect of lateral pressures may be accounted for in analyses. Testing procedures for the mechanical Field measurements taken from test sites were compared with predictions of potential heave using eight published empirical methods, the empirical equations developed as part of this study, and program ULTRAT. Preliminary analyses of heave with time using the empirical equations were also compared with field observations. The results indicate that several methods provided useful predictions of potential heave of the field test sections. These methods include the empirical equations developed as part of this study and use of ULTRAT. The soil suction model provided upper and lower limits of heave at the field test sections if all or 1/3 of the volumetric swell, respectively, is assumed to occur as heave in the vertical direction. Heave with time predictions are burdened with the problem of determining effective field coefficients of permeability or swell. Effective coefficients of permeability or swell are a function of the availability of water as well as a measure of the field test Sections. These methods include the empirical equations developed as part of this study and use of ULTRAT. The soil suction model provided upper and lower limits of heave at the field test sections if all or 1/3 of the volumetric swell, respectively, is assumed to occur as heave in the vertical direction. Heave with time predictions are burdened with the problem of determining effective field coefficients of permeability or swell. Effective coefficiens of permeability or swell are a function of the availability of water as well as a measure of the field permeability. Maximum upper limits of 0.0001 ft/day and 0.092 sq ft/day for the effective coefficients of permeability and swell, respectively, were determined for the soils beneath the field test sections.

  • Corporate Authors:

    U.S. Army Waterways Experiment Station

    3909 Halls Ferry Road
    Vicksburg, MS  USA  39180-6199
  • Authors:
    • Johnson, L D
  • Publication Date: 1978-7

Media Info

  • Features: Appendices; Figures; Tables;
  • Pagination: 194 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00183659
  • Record Type: Publication
  • Report/Paper Numbers: Tech Report S-78-7 Final Rpt.
  • Files: TRIS, ATRI
  • Created Date: Dec 3 1978 12:00AM