Assessment of Stability of Slopes under Drawdown Conditions

TLDR

Slope stability under submergence is traditionally assessed with Morgernstern charts or proprietary computer programs, but these methods are limited by geometry, material properties, and analysis assumptions, making finite‑element analysis a more versatile alternative for complex geometries. This study aims to develop finite‑element‑based operating charts for drawdown conditions that can be applied to real dam and reservoir structures. The authors use finite‑element modeling to generate operating charts that relate drawdown rates to slope stability for practical engineering use.

Abstract

The traditional approach for estimating the stability of slopes under different submergence conditions is the charts of Morgernstern and, more recently, proprietary computer programs, both utilizing limit-state analyses. The chart approach is limited by geometry and material property considerations and the limit-state approach by assumptions about analysis method and failure mechanism. The finite-element method offers a powerful method for analyzing complex geometries and properties of slope stability problems, but may be unattractive for routine use by supervisory staff. By comparison a chart based approach is useful, particularly when setting operating conditions on, for example, drawdown rates for dams and reservoirs. This paper seeks to explore the use of the finite-element method to produce operating charts for such circumstances that should be applicable to real structures.