Correction Factors for Undrained LE Analyses of Sensitive Clays

Abstract

Correction factors to be used in conventional undrained stability calculations in order to account for post peak strain softening behaviour of sensitive clays, has been recommended based on an extensive sensitivity study with advanced finite element simulations. It is found that a correction of the material factor is preferred compared to a reduction of the shear strength. The input parameters to the sensitivity study that had the highest correlation with the required correction factor were the shear strength increase with depth and the brittleness, which is the rate of shear strength reduction with strain. In a large block sample database of sensitive Norwegian clays, there was no clear correlation between the brittleness and the sensitivity. Hence, classification of the clays based on the sensitivity is not recommended for evaluating the effect of strain softening on the capacity.