Abstract: A rock chamber structure for containing gas or liquid under pressure is provided with a lining arrangement which transmits pressure of the contained gas or liquid to the surrounding rock while preventing build-up of external water pressure on the lining arrangement. A compressible drainage layer of loose granules is disposed between the rock and a concrete layer of the lining arrangement, and a thin metal sealing membrane is mounted to the concrete layer to seal the rock chamber. The concrete layer is anchored to the surrounding rock by expandible bolts which permit displacement of the concrete layer toward the rock. Pressure from the contained medium is transmitted to the surrounding rock through the metal liner, the concrete layer, and the drainage layer, while the drainage layer prevents the build-up of external water pressure.