Hydro-mechanical behaviour of shot-clay bentonite

Experimental tests were conducted to characterise the hydro-mechanical behaviour of shot-clay MX-80 bentonite. Granular bentonite was mixed continuously with water and shot on the walls of a tunnel section at the Grimsel Underground Research Laboratory (URL), in Switzerland. The shot-clay was placed to create a layer of bentonite in direct contact with the host rock to avoid preferential water and/or gas flow along the tunnel wall. Samples for an experimental programme were collected during the shooting. Results from an experiment, conducted under controlled total suction to analyse the hydro-mechanical behaviour of the material, are shown.