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 $0.01,\mathrm{ }0.07,\mathrm{ }0.14,\mathrm{ }0.7,\text{ and }1\mathrm{\%}$ 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.

本研究调查了伊朗南部格什姆岛的钙质砂的不排水行为。该研究是通过不排水的循环和单调的污点控制的三轴试验对两个相对密度（40％和70％）和不同的有效围压进行的。五个不同的应变幅度，包括$0.01，\mathrm{ }0.07，\mathrm{ }0.14，\mathrm{ }0.7，\text{ 和 }\mathrm{1个}\mathrm{％}$被用于循环三轴试验。另外，Qeshm钙质砂的疏松和致密样品均表现出相当的延展性，并且在剪切样品时未观察到在单调载荷下的清晰破坏面。有效围压的增加导致循环荷载作用下较高的过剩孔隙水压力。在增加的周期性应变幅度中，这一增量特别明显。相对密度和超固结比（OCR）的增加增强了剪切模量并降低了液化潜力。此外，通过增加剪切应变和有效围压来增加颗粒破碎。然而，相对密度的增加降低了Qeshm钙质砂的颗粒破碎。