Prestressed Concrete-Lined Pressure Tunnels

Hydropower can be a source of sustainable energy, provided environmental considerations are taken into account and economic aspects of hydropower design are addressed. Using concrete-lined pressure tunnels instead of steel pipes may be economically attractive but may also have limitations due to the low tensile strength of concrete. This research indicates that prestressing the concrete lining by grouting the circumferential gap between the concrete lining and the rock mass at high pressure can enhance the tunnel bearing capacity and increases safety. Moreover, grouting will seal off the seepage into the rock mass, which is favourable for tunnel stability.