The creep response of four remolded soils and undisturbed soils from two landslide sites is presented. A method for obtaining the yield stress of soil from creep test data is presented and discussed. "Viscosity diagrams", showing the location of the yield stress is approximately 50 percent of peak stress, were obtained from conventional triaxial tests. There is more scatter in data from undisturbed soils than in data from remolded soils. Mohr's failure envelopes, constructed from yield stress data, give internal friction angles having values from approximately five to ten degrees. Strength data, calculated indirectly from peak relaxation modulus, are also presented.

Stability analyses are presented on two selected landslides. Analyses are made and compared using peak, " Residual", and yield stresses. Results indicate yield stress should be considered when designing earth structures.

Report Date


Report Number

No. 382

Digital Object Identifier



The contents of this report reflect the views of the authors who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Bureau of Highways. This report does not constitute a standard, specification, or regulation.