Cyclic liquefaction behavior of coral sand-gravel soil under anisotropic consolidation conditions

The wide-graded coral sand-gravel soil is commonly used as filling or foundation materials in onshore and offshore engineering projects and often under anisotropic stress conditions. A series of undrained cyclic loading tests are conducted using a testing system combined with triaxial apparatus and bender element to investigate the cyclic liquefaction response of coral soil under various consolidation conditions. The results indicate that compared to the isotropically consolidated specimens that exhibit cyclic mobility response, the anisotropically consolidated coral soil usually fails due to the excessive accumulation of residual deformation. Moreover, the presence of the initial static deviatoric stress slows down the pore pressure buildup, thereby increasing the resistance of soils to cyclic liquefaction. An approximately unique relationship is observed between the normalized maximum shear modulus and the liquefaction resistance of coral soil with varying static deviatoric stresses and effective confining pressures, suggesting that the evaluation methods based on the maximum shear modulus or shear wave velocity are highly suitable for assessing the liquefaction potential of coral soil.