Moisture infiltration into earth slopes and structures constructed of high-plasticity clays will lead to a reduction in soil suction and strength that can ultimately result in stability failure. This research presents a rational analysis of this process that: establishes a relationship between soil suction and strength, and provides a framework for predicting the time rate of strength loss due to moisture infiltration into an earth mass. This research utilizes a generalized form of the Mohr-Coulomb failure criterion to characterize the effects of suction on soil strength. A diffusion equation governs changes in soil moisture and suction. This equation is in general non-linear for unsaturated soils; however, this research uses a linearized formulation through appropriate transformation of variables. This research also presents methods for estimating the necessary material parameters needed for input into the moisture diffusion model. The suction-strength relationships and moisture diffusion analyses are applied to back-analyzing a number of shallow slope failures in Texas high-PI (plasticity index) clays. The moisture diffusion analysis is also extended to typical Texas Department of Transportation earth-retaining structures to predict decreases in suction during the life of these structures. Based on these suction predictions, estimates of soil strength within an earth structure as a function of location and time are possible.

  • Supplemental Notes:
    • Research Project Title: Long-Term Strength Properties of High-PI Clays Used in Embankment Construction.
  • Corporate Authors:

    Texas Transportation Institute

    Texas A&M University System, 1600 E Lamar Boulevard
    Arlington, TX  United States  76011

    Texas Department of Transportation

    Research and Technology Implementation Office, P.O. Box 5080
    Austin, TX  United States  78763-5080

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Aubeny, C
    • Lytton, R
  • Publication Date: 2003-2


  • English

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: 100 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00972252
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/TX-03/2100-1,, Research Report 2100-1,, TTI: 0-2100
  • Contract Numbers: Project No. 0-2100
  • Created Date: Apr 30 2004 12:00AM