A new method to quantify breach sizes for the flood risk management of concrete arch dams

Abstract

When predicting dam‐break floods and the associated risk zones for the flood risk management of dams, the breach size must be determined by considering the complex structure of the dam body under the effects of different loads. To predict the breach size quantitatively, this article proposes the concept of an element group, comprising a group of elements through the dam body. The dam‐body safety status is simulated by using the three‐dimensional (3D) finite element model ANSYS and is quantified by the element reliability index β for various loads such as hydraulic and earthquake loads. A new structural reliability method for calculating the breach size was developed to quantitatively predict the failure likelihood of a dam. This new method is more intuitive and reasonable than the point safety factor k. It allows for a more accurate and quantitative prediction of the breach size of new or existing dams. An existing Roller Compacted Concrete arch dam was taken as an example to demonstrate the applicability of the new method.