LONG-TERM STRENGTH OF COMPACTED HIGH-PI CLAYS
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.
- Research Project Title: Long-Term Strength Properties of High-PI Clays Used in Embankment Construction.
Arlington, TX USA 76011
Austin, TX USA 78763-5080
Washington, DC USA 20590
- Aubeny, C
- Lytton, R
- Publication Date: 2003-2
- Features: Appendices; Figures; References; Tables;
- Pagination: 100 p.
- TRT Terms: Compacted clays; Earth walls; Embankments; Linear equations; Plasticity index; Slope stability; Soil suction
- Uncontrolled Terms: Mohr-Coulomb failure criterion; Moisture diffusion; Soil strength
- Subject Areas: Geotechnology; Highways; I42: Soil Mechanics;
- 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
- Files: TRIS, USDOT, STATEDOT
- Created Date: Apr 30 2004 12:00AM