Energy method for analyzing dynamic pore water pressure model for tailing soil

By using the stress-controlled undrained dynamic triaxial cyclic shear tests, relationship between accumulative energy dissipation of tailing soil and pore water pressure is investigated based on the critical factors, namely, cyclic stress ratio and consolidation stress ratio. The test results indicate that, during the process of cyclic shear, the increase of pore water pressure is closely related to the accumulative energy dissipation of plastic strain and viscous properties. A critical state, when the cyclic stress ratio varies within the range of 0.205~0.238 and the consolidation stress ratio varies in 1.0~1.3, occurs between the pore water pressure and energy. Therefore, through nonlinear regression analysis, the energy model for pore water pressure of saturated tailing soil is preliminarily established based on the cyclic stress ratio and the axial-radial consolidation stress ratio, and it can be adequately employed to demonstrate the variations of pore water pressure without considering the uncertainty of cyclic loading number which can otherwise hinder the establishment of the model. In addition, the proposed model may also be a valuable source of reference for predicting the development of pore water pressure of saturated soil under cyclic loading.