Undrained monotonic and cyclic behavior of Qeshm calcareous sand
Javad Saeidaskari, Mahdi Alibolandi, Alireza Saeedi Azizkandi
Abstract
The present research investigates the undrained behavior of calcareous sand of Qeshm island in the south of Iran. The study was performed through undrained cyclic and monotonic stain-controlled triaxial tests on two relative densities (40 and 70%) and different effective confining pressures. Five different amplitudes of strains including 0.01, 0.07, 0.14, 0.7, and 1% were applied for cyclic triaxial tests. Additionally, both loose and dense samples of Qeshm calcareous sand show rather a ductile behavior and clear failure plane under monotonic loading were not observed upon shearing of the samples. The increase in effective confining pressure led to higher excess pore water pressure under cyclic loading. This increment was especially clear in larger amplitudes of applied cyclic strain. The increase in relative density and over consolidation ratio (OCR) enhanced the shear modulus and reduced liquefaction potential. Moreover, particle breakage was increased by increasing shear strain and effective confining pressure. However, the increase in relative density decreased particle crushing of Qeshm calcareous sand.