A study of slope stability analysis

Richard J Deschamps, Purdue University


A study was made to investigate the potential errors in stability assessments when using conventional limit equilibrium analysis. The primary objective is to provide insight into the factors influencing the stability of slopes. This objective is achieved by examining the stability of excavated slopes for drained conditions utilizing a two-wedge analysis and for undrained conditions using finite element analysis with the Modified Cam Clay soil model. The key aspects investigated are the influence of initial stress state on the final distribution of mobilized stresses and how the distribution of stress affects perceived stability.^ The significant influence of initial stress state on the final distribution of stress and strain is demonstrated. It is shown that the location along potential slip surfaces where the maximum mobilization of shear stresses will occur is related to the initial stress state. These findings have important implications in strain softening soils which may lead to progressive failure. Other results include: development of a new measure of stability, called the safety margin (SM), which is dependent on the distribution of shear stresses; illustration of the importance of considering soil strength profiles varying with depth as compared to an "equivalent" constant value; demonstration of the advantages in considering partial safety factors in deterministic analyses; and the introduction of a critical safety factor (SF$\sb{\rm Crit})$ at which local yielding will not occur. ^




Major Professor: Gerald A. Leonards, Purdue University.

Subject Area

Geotechnology|Engineering, Civil

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