Dynamic pore water pressure model for liquefiable soils based on theory of thixotropic fluid

It is a key problem to confirm the growth process of dynamic pore pressure of the liquefiable soils in the analysis of liquefaction potential of soils or evaluation of liquefaction effect. Based on the structural theory of the Moore thixotropic fluid, 32 groups of undrained cyclic triaxial experiments on different types of soils are performed to verify the corresponding relationship between internal structure parameters of soils and dynamic pore pressure in the whole liquefaction process. The thixotropic mechanism induced by the pore water pressure in the liquefiable soils under cyclic loading is confirmed. Moreover, a dynamic pore pressure growth model for the liquefiable soils is proposed based on the rate equation for the thixotropic fluid induced by pore pressure. It is found that the generation and growth mechanism of dynamic pore pressure implied in the proposed model can be explained reasonably from the viewpoint of energy. The experimental results show that the parameter of growth rate of dynamic pore pressure in the model is closely related to the effective confining pressure, initial relative density and cyclic stress ratio. The proposed model is used to simulate the undrained cyclic triaxial experiments, and accordingly the rationality and reliability of the model are proved. Finally, the main characteristics and potential applications of the proposed model are discussed. This study provides a new technical means for the liquefaction analysis of soils.