Structural Analysis of the Embedded Spiral Case in the Three Gorges Hydropower Station

Abstract

The 15th turbine unit in the Three Gorges hydropower station was proposed to use a complete bearing spiral case, a first in large hydropower stations in China. This research performs a three-dimensional, nonlinear, finite-element statical analysis of the concrete structure based on a damage-plasticity model to study the reliability of the spiral case and the safety of the turbine unit under various working conditions. Detailed analyses performed include stress distribution in the spiral case and reinforcement bars, range of potential damages in the surrounding concrete, and displacement of the overall structure. The computational results indicate that the embedment method proposed for the 15th turbine unit at the Three Gorges hydropower station is feasible and will satisfy safety and design requirements.