2023 – Update of the Unified Method for Estimating Probabilities of Failure by Internal Erosion and Piping

Robin Fell, Mark Foster

The Unified Method for Estimating Probabilities of Failure by Internal Erosion and Piping (AKA The Piping Toolbox) was developed in 2006-2008 by representatives of USACE, USBR, URS and UNSW. It has been used extensively throughout Australia for risk assessments and design of dam upgrades. It is used as a reference document by USACE and USBR (now Reclamation).

Since 2008 there have been many developments in the understanding of the mechanics of internal erosion relating to concentrated leak erosion, backward erosion piping, suffusion, global backward erosion and contact erosion, and experience in the use of the Toolbox. As a result, the 2008 Toolbox is now outdated in several ways and is being updated.
This paper describes the main changes which have been made to the document. It will be available for trialling by those carrying out risk analyses by the end of 2023.

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