Analysis of stilling‐basin damages

In a changing climate, many hydraulic structures are exposed to higher risks in combination with aging issues. Analysis of structural damages plays a significant role in assurance of safe and sustainable hydraulic operation.

Stilling basins are commonly placed downstream of spillways (also bottom outlets and culverts), which provide a means to absorb or dissipate the energy from spillway discharge. Failure to properly design and maintain a stilling basin could lead to destructive consequences, e.g., basin breach and floatation, undermining of the spillway, erosion of the outlet channel and/or embankment material, and ultimately dam failure. Thus, the safety of hydropower dams relies on such an energy dissipation facility.

The aim of this project is to enhance the understanding of failure mechanisms of stilling basins and to develop a reliable and physically-based damage model for stilling basins. Focus is placed on the effects of turbulent flow conditions, joint geometry (gap, offset), venting conditions, aeration, uplift pressure transmitted through a joint, etc., which have not yet been systematically studied.

The project provides improved knowledge in modeling high-velocity flows and dynamic pressure fluctuations for stilling basin applications and establishes a methodology for basin structural stability analysis where best-practice design recommendations will be outlined. The project contributes to safe operation and rehabilitation of spillway structures subjected to high damage risks, which are expected to increase in magnitude and frequency due to climate change.