Validation of strain/energy-based pore pressure model in one-dimensional response analyses using centrifuge tests

Abstract

The results of cyclic strain-controlled tests performed on reconstituted specimens of Ottawa sand F-65 using the combined triaxial simple shear (TxSS) apparatus were used to establish a strain/energy-based pore pressure model. The model was utilized in conjunction with the sigmoid function (SIG4) to simulate the cyclic behavior of Ottawa F-65 sand under stress and strain loading conditions using FLAC at the element-level and in 1-D effective stress analysis. A counterpart set of cyclic stress-controlled direct simple shear (DSS) tests was performed to assess the predictive capability of the numerical model to determine the liquefaction potential curves. Two dynamic centrifuge tests were simulated using the proposed model and Finn model, and a satisfactory comparison of the observed and computed responses in terms of pore water pressure generation at different depths was obtained. Furthermore, model validation was carried out by applying real earthquakes from the Western United States (WUS) to a hypothetical soil deposit and then comparing the liquefaction triggering according to published liquefaction charts. A good agreement between the numerical results and the published charts confirms the applicability of the proposed strain/energy-based model in 1-D response analysis and liquefaction triggering assessment.