... limits the use of this innovative concept. This manuscript will review the history of the use of unlined pressure tunnels / shafts in the world and presents prevailing design approaches in the use with the aid of the use of some very important cases of failures and successes where unlined / shotcrete...

... Abstract The transition zone, i.e. where the pressurized water enters the steel lined section of the waterway, is a key component of the entire tunnel system in any underground hydropower project utilizing unlined pressure tunnels. Not only is it important for conveying the pressurized water...