Experiment and theory research on the pore pressure unloading characteristics of saturated clay under isotropic consolidation conditions

Abstract

When a gravity structure, such as a caisson or a jackup spudcan, is pulled out from the saturated soft clay foundation, a negative pore pressure will be developing, which may greatly increase the pullout force. Therefore, it is very important to estimate the negative pore pressure developed in the soil during the unloading process. The development of excess pore pressure is studied based on the triaxial extension tests under the isotropic consolidation conditions. By combining the modified Cambridge model with the Henkel's approach, the mechanism of negative pore pressure generation is revealed and a method is developed to predict the magnitude of the negative pore pressure. Meanwhile, the d..