An energy-based model for the generation of excess pore water pressure in saturated coral sand

A series of undrained cyclic shear tests was carried out on saturated coral sands, with different initial physical states, as they were subjected to rotations of 90 degrees in the paths of cyclic stress with various initial orientations under isotropic conditions. An important finding is that the cumulative dissipated energy required for liquefaction (W-s) was significantly affected by their fines content (FC), relative density (D-r), and effective stress of consolidation (p ' 0), but was independent of the conditions of cyclic loading. W-s increased significantly with the increase in p ' 0. When FC was less than the threshold fines content, W-s increased with FC and decreased with an increase in D-r. The equivalent intergranular void ratio (e*) was introduced to reflect the effects of FC, physical states of the particles, and inter-particle contact on the physical properties of coral sand. The results revealed a unique relationship between e* and W-s at p ' 0 = 100 kPa. Furthermore, the unified model of the relation between the normalized cumulative dissipated energy and the ratio of excess pore water pressure (EPWP) followed an arc-tangent function. This model can be used to characterize the generation of EPWP with the cumulative dissipated energy of fine-grained sand under isotropic consolidation conditions.