Hydromechanical behaviour of reinforced concrete linings in hydraulic tunnels: transient

The deregulation of the power market and the growing reliance on electricity generation from variable renewable energy sources have significantly altered the operational dynamics of hydropower plants. The shift from hydropower systems designed to function as base load plants to pumped storage schemes (PSPs) characterised by more frequent load changes and start/stop sequences of operations significantly increased the relevance of transient conditions with respect to static ones. While existing research has predominantly focused on the effects of water pressure on tunnel linings under steady-state conditions, little to no attention has been given to transient conditions. This paper addresses this gap in the current literature by presenting a novel model for evaluating the behaviour of reinforced concrete linings in hydraulic tunnels during transient conditions. This approach allows for a comprehensive understanding of the intricate interaction between fluid flow, tunnel structure, and rock mass. The insights gained have the potential to significantly advance the assessment and safeguarding of the structural integrity of hydraulic systems operating in PSPs.