The Effect of Shape and Stiffness of Originally Different Marine Soil Grains on Their Contractive and Dilative Behavior

摘要

Laboratory research was conducted to compare the monotonic behavior of two different marine calcareous sands - Hormuz Island (HI) and Bushehr Port (BP) - with siliceous sand named Firoozkuh sand (F). A series of undrained isotropically consolidated triaxial tests was performed on reconstituted specimens of these sands. In this experimental investigation, their contractive and dilative behaviors were evaluated. The effect of some important parameters, such as relative density and confining pressure on the behavior of these specimens was studied. To analyze the effect of shape and stiffness (resistance to particle breakage) on the contractive and the dilative responses of these soils, the influence of axial strain on the crushability of the calcareous soils was assessed. Thereafter, the undrained behavior of the soils was analyzed, using two parameters, which represented a normalized variation of excess pore water pressure in two phases of monotonic triaxial tests. The contractive and dilative behavior of the two different calcareous sands was compared to the siliceous sand. The results showed that particle shape played a key role in the behavior of soils in contractive phase. However, the shearing response of the used carbonate soils was more affected by particle crushing in dilation.