Large-Scaled Shotcrete Lining in the Deep Cavern at the Imaichi Underground Power Station

Abstract

Tokyo Electric Power Company is now consturcting the Imaichi Underground Power Station with the cross section area of 1420m². In the design of the power cavern, the horse-shoe shape section is adopted to avoid the stress concentration at the stage of opening induced by high initial rock pressure more than 100kg/cm². Rock anchoring, rock bolting and shotcreting, conventionally used for temporary works, are also utilized as the permanent supporting system on the basis of the NATM concept. This paper describes the outline of the design and construction of shotcreting.