Experimental study on characteristics of pore water pressure and dissipated energy of saturated calcareous sand under complex loading conditions

Calcareous sand, the special soil, is the main material for the filling of islands and reefs in the South China Sea, which is biogenic sediments and skeletal remains of marine organisms. It is of great importance to study its dynamic characteristics. By a series of undrained cyclic triaxial tests on the calcareous sand, the characteristics of pore water pressure are investigated. Besides, the energy method is used to establish the relation between the pore water pressure and the dissipated energy. The results show that the ultimate residual pore pressure ratio of the saturated calcareous sand increases first and then decreases with the change of consolidation stress ratio. The accumulated dissipated energy during cyclic loading is related to the initial static shear stress ratio and relative density of the sample, and has few influences on the cyclic stress ratio. The dissipated energy of the saturated calcareous sand under different test conditions can be predicted by the energy model. The research provides theoretical basis and technical support for the stability analysis of calcareous sand foundations.