When the Fundão Dam failure led to tailings being deposited near the Candonga Dam that stopped operations at the Candonga Hydroelectric Power Station, three sheet piling walls had to be designed to dredge the tailings. Terratek was responsible for performing numerical analysis on one of the walls and simulating the tailings excavation to obtain horizontal displacements. The project presented complex geometry and many finite elements and stress points, resulting in a model rendering the calculation time impractical. They needed flexible modeling software capable of handling the voluminous model elements and calculations.

They selected PLAXIS to model the soil behavior and wall, and determined the wall presented large horizontal displacement reaching 800 millimeters on the top. The 3D modeling and analysis results led to a design update for a proper instrumentation system to predict wall failure. The project demonstrates the importance of using accurate 3D modeling technology to predict structural behavior and facilitate design of a monitoring scheme.