UNSTABLE ROCK AND ITS TREATMENT SNOWY MOUNTAINS SCHEME

Fig. 2.—Eucumbene-Snowy Tunnel, typical cross sections.

Fig. 3.—Granite of good quality with mostly tightly closed joints, left untreated, in Eucumbene-Snowy Tunnel.

Fig. 4.—Tunnel through major fault zone, excavated by crown and wall plate drifts, supported by 8 in. x 6in. ribs at 2 ft centre, and invert struts now embedded in concrete.
Underground power stations
Similar problems concerning rock instability and its treatment occur on a larger scale in connection with the underground power stations, where extensive use has been made of rock in-place as a constructional material.