A SIMPLIFIED PROCEDURE FOR PROBABILITY-BASED φ_u=0 STABILITY ANALYSIS

抄録

The objective of this study is to provide a simple yet accurate procedure for the probabilistic stability analysis of an embankment constructed on a soft clay with finite thickness. The analysis is based on the conventional φ_u=0 and circular arc slip surface assumptions.The probabilistic soil profile description with respect to the undrained shear strength within a clay deposit is given first introducing a simple stochastic process. This is shown to be a general expression for the spatial variation of the strength of clays including the conventional deterministic soil profile as a special case. The probabilistic description of the soil profile is, however, transformed into the set of eight different deterministic soil profiles, each of which is a three-layered system with three different strengthes. Through the composition of these multi-layered systems, it is demonstrated that all the possibility in the distribution of a factor of safety can be covered by only eight times of execution of the deterministic, and then, conventional slope stability analysis for eight deterministic soil profiles. From this, the layered system is called in this study an equivalent multi-layered system.The developed procedure is illustrated in the case studies including a multi-failure mode problem, from which the simplicity as well as the accuracy of the proposed method is verified for the use in practical design.