THE MECHANICS OF UNCEMENTED CARBONATE SANDS

The mechanical behaviour of a typical biogenic carbonate sand was investigated using triaxial testing at standard and also at high pressures up to 8 MPa. The test results show that despite the particle breakage which is characteristic of these soils, their behaviour is still qualitatively similar to that observed for more commonly encountered soils, and is consistent with the principle features of critical state soil mechanics. The higher stresses used in these tests were an order of magnitude greater than are generally used in soils testing, and the values of some individual soil parameters were found to be outside the range of normal experience. Micrographic and gradings analyses were used to examine the influence of isotropic and shear stresses on particle breakage. Triaxial test results illustrate the influence of this breakage on the mechanical behaviour of the soil.