The Place of Stability Calculations in Evaluating the Safety of Existing Embankment Dams

Thorough investigations of site conditions and construction records should have precedence over stability analyses for determining the safety of embankment dams.
The purpose of evaluating the safety of an existing embankment dam is to ensure that the catastrophic loss of the reservoir will not occur. Many reports in which the safety of existing dams is evaluated relate the safety to the results of stability analyses. Yet,seismic considerations aside, stability analyses are often irrelevant and may even be misleading.
To be sure, one of the great achievements of soil mechanics has been the development of limit-equilibrium methods of stability analyses. Every soils student learns about them. Sophisticated computer programs exist for carrying them out. They have an important place in embankment dam engineering, primarily in design, but they can be misleading in evaluating dam safety if too much dependence is placed on the numerical values of factors of safety derived from them.