Experimental study on cumulative deformation characteristics of coral sand under long-term cyclic loading

The drained triaxial shear tests on isotropic and K₀ consolidation of coral sand samples taken from the South China Sea reveal that the consolidation path has a significant effect on the strength characteristics of the coral sand. On this basis, using the K₀ consolidation condition, a series of long-term drained cycle triaxial tests with different confining pressures and cyclic dynamic stress ratios are carried out. The results show that the coral sand has a threshold cyclic dynamic stress ratio, which makes its particles obviously broken. The stability theory can be used to explain the cumulative deformation development patterns of the coral sand under long-term cyclic loading with different dynamic stress ratios. Based on the results of static and dynamic test results, the relative deviator stress level is introduced to establish an explicit model for the axial residual cumulative deformation of the coral sand, which can reflect the initial consolidation state and cyclic dynamic stress ratio of the coral sand under drained cyclic loading. The proposed model is of positive significance for predicting the long-term settlement of the coral sand foundation under cyclic loading.