Swelling rock desaturation and its influence on underground structures

The influence of swelling rock desaturation on its behavior in tunneling is described. The swelling potential of the desaturated rock will be more pronounced, when compared to similar rock in saturated state. A new characteristic curve for the swelling rock mass was defined based on the approach defined by Kovari et al. (1988). At that, the influence of desaturation on activation of the swelling rock potential was taken into account. The proposed curve is nonlinear on a semilogarithmic scale which emphasizes even more the observed phenomenon that a small allowed floor heave significantly reduces the swelling pressure, i.e. that a small lining resistance may significantly reduce the floor heave.