this report considers the problems of assessing the stability of embankments constructed on soft alluvial deposits of recent origin. current methods of assessing stability are reviewed and the limitations and range of application of both the total and effective stress approaches to the problem are discussed. a major problem in assessing the stability is the determination of reliable values for the shearing strength of soft subsoils. the total stress method of analysis is sufficient for routine design purposes where an adequate factor of safety can be achieved economically, although there is evidence that this method may seriously over-estimate the stability. the effective stress method of analysis is more flexible but requires information on the porewater pressures in the subsoil and as these vary with time and applied loading they are difficult to predict reliably in variable deposits. however, the effective stress method linked with field measurements of porewater pressure has particular advantages where the stability of the completed works requires some gain in strength in the subsoil resulting from consolidation during the construction period. stability charts based on a simplified method of interpreting the results of field measurements of porewater pressure have been successfully used at a number of sites for controlling the construction. (a).

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