Abstract
Blocks of undisturbed sample of a natural sedimentary sand called here Hayakawa sand were procured from the construction site of a pneumatic caisson. A series of drained triaxial compression tests and one-dimensional, isotropic consolidation tests was performed on the undisturbed and disturbed samples to investigate their stress-strain relationship and strength behaviour in view of soil structual characterristics, namely, particle crushing, anisotropy and cementation. The Hayakawa sand particles were crushed more by shearing than by isotropic compression at the pressure of around 3000kN/m2. The undisturbed Hayakawa sand exhibits slight anisotropy at low stress levels and the anisotropy becomes less marked as the confining pressure is increasing. The Hayakawa sand had very small amount of cohesion of as small as 5kN/m2. The deterioration of the cohesion was nicely modelled in an exponential manner proposed by Ooi et al..
