Influence of the intermediate principal stress on the stress–strain–strength behaviour of a completely decomposed granite soil

The most widely encountered soil type in Hong Kong is completely decomposed granite (CDG). In this paper, the influence of the intermediate principal stress through b-values on the stress–strain–strength behaviour of a recompacted CDG soil is investigated by using a true triaxial test system with a new loading device. The experimental results show that the deviator stress decreases as the b-value increases from 0 to about 0·8, and the deviator stress is then increased slightly for b = 0·8 and b = 1·0. The development of a shear band appears, having caused failure for b-values in the range 0·2–0·8.