TRIAXIAL TESTING OF NATURALLY CEMENTED CARBONATE SOIL

Cemented carbonate (calcarenite) soils obtained from the North West Shelf of Australia were subjected to conventional and stress-path triaxial tests. Natural calcarenite specimens were found to have wide variations of dry density and degree of cementation. These variations complicate interpretation of the test data, and need to be taken into account. To achieve this, it is suggested that tensile tests be performed on off-cuts to estimate the degree of cementation. The responses of the natural calcarenite samples were found to be similar to other cemented and structured soils. Stress-path tests were performed to investigate the shape of the yield locus. An elastic region was identified in which the shear modulus is constant and the bulk modulus varies linearly with mean effective stress. The cementation was found to increase the shear modulus and size of the yield locus, but to have little effect on the volumetric