Ninety-one well-documented geotechnical failures are reviewed. The case studies involved the failure of embankments, footings and load tests, excavated slopes, and natural slopes. Seventy-five of the geotechnical failures had been analyzed using total stress analysis. Sixteen of the case failures had been analyzed using effective stress analysis. Based on a review of these case studies, there are discrepancies between predicted and actual stabilities of geotechnical structures and there is a tendency tu overestimate the factor of safety. Differences that may arise between predicted and actual performances are discussed and examined and guidelines are proposed for evaluating the potential of successfully applying total stress and effective stress analyses. The simple guidelines make use of index tests such as the liquid limit, plastic limit, natural water content, and liquidity index.

With regard to embankments on clay foundations, assumptions commonly made regarding the shear strength of the embankment are discussed. A mathematical model based on embankment cracking is presented in terns of effective stress, although total stress conditions also may be analyzed. The model solution yields a depth of tension crack that is based on the mobilized shear strength parameters. The depth of tension obtained from the model analysis is compatible with the factor of safety. The proposed embankment failure model equations have been programmed for the computer and form an integral part of a newly developed, generalized slope stability computer model and program (HOPK-I). Numerical examples selected from published sources are reanalyzed using the failure model. These results are compared to published results of the selected examples.

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