ABSTRACT
This chapter addresses the nonlinear character of failure envelope of a nonplastic compacted silty-sand. Linear and nonlinear strength functions were fitted to experimental results from consolidated-undrained triaxial tests to derive the strength parameters of linear and nonlinear failure envelopes. The importance of incorporating the nonlinear character of soil failure envelope in slope stability computations has been demonstrated by two dimensional limit equilibrium and finite element analyses as well as three dimensional slope stability studies. Linear and nonlinear strength functions were fitted to laboratory triaxial test data to derive the failure envelope of a compacted silty-sand. The derived nonlinear failure envelope also predicted lower strength values than the linear strength model within the range of very small normal stresses uncovered by the experimental information. This departure from linearity is usually associated with smaller computed safety factors in a conventional slope stability analysis based on the nonlinear strength model, implying therefore a safer slope design.
