Abstract
Blocks of undisturbed sample of scoria were procured from the construction site of a pneumatic caisson. A series of triaxial, plane strain compression tests was carried out for the scoria both in undisturbed and disturbed states. The results showed that (1) the undisturbed scoria is highly compacted with a relative density of more than 100%, and an apparent cohesion of about 100kPa, (2) the behaviour of the scoria changes from that of a dilatant brittle material to that of a plastic material in the confining pressure range of 700 to 1500kPa, exhibiting volume reduction with particle crushing, (3) the difference in behaviour between triaxial and plane strain compression tests gradually diminishes with an increase in confining stress, (4) the cohesion term mobilizes to the full at the axial strain of 2% and is destroyed at about 8% of the axial strain.
