Experimental investigation of cyclic failure mechanism of saturated coral sand under various consolidation conditions

This study reports a series of undrained cyclic triaxial tests that were conducted on Nansha coral sand by using the dynamic triaxial apparatus of the GDS to investigate the effects of the consolidation ratio ( K c ), cyclic stress ratio ( CSR ), and relative densities ( D r ) on the characteristics of liquefaction of saturated coral sand. The results indicated the presence of two modes of generation of axial strain ( ε a ) in saturated coral sand: cyclic mobility (without initial shear stress) and the accumulation of plastic strain (with initial shear stress). By considering liquefiable coral sand as a fluid, the coefficient of average flow ( κ ) was introduced to determine the characteristics of flow of saturated sand under cyclic loading. Under isotropic consolidation, the value of κ of saturated coral sand was not sensitive to the CSR but decreased with an increase in D r , indicating that its fluidity had weakened. The fluidity of saturated coral sand decreased with an increase in the initial shear stress. Under anisotropic consolidation, u e2.5