Design and construction technology of the engineered scale plug in the TSX

Sugita, Yutaka ; Masumoto, Kazuhiko*

JNC has conducted the international joint project "Tunnel Sealing Experiment (TSX)" with AECL at Underground Research Laboratory-(URL) in Canada. Full-scale sealing technologies are applied to the underground tunnel in the TSX. Sealing technologies contain backfilling, plugging, grouting and so on. Since development of the plugging technology has impact to the whole sealing technology, understanding of the sealing performance of the plug is one of the most important problems. The TSX has full-scale concrete plug and clay plug. The sealing performance of the plugs has been monitored with the various sensors in and around the plugs, and assessed by the monitored data. This report summaries the design and construction technology of the plugs in the TSX. The design of the plugs focused on the impervious (seepage control). The concrete plug selected the shape and the size of the body and the size of the key considering the attachment between plug and rock mass. The clay plug selected the shape and the size of the key considering the volume of the EDZ. The material of the concrete plug was Low-Heat High-Performance Concrete. The material of the clay plug was pre-compacted bentonite blocks with sand. Feasibility of design and construction of both plugs were demonstrated with engineer scale and in-situ full-scale plugs.