Energy-based evaluation of excess pore pressure using damage potential

An energy-based model for the prediction of excess pore pressure (EPP) and evaluation of liquefaction potential in saturated sands is proposed using dissipated energy (w_d) and damage potential. The damage concept is adopted for the development of the proposed model. Undrained dynamic triaxial tests are conducted using both regular sinusoidal and irregular earthquake loading conditions. Based on test results, the normalized cumulative excess pore pressure ratio (NCER)-the normalized cumulative dissipated energy (NCW) as a function of w_d and cumulative absolute velocity (CAV)-is developed. Additionally, a procedure is presented for the evaluation of EPP and determination of model parameters for the proposed model. It is found that model parameters for the proposed model can be estimated from the NCER-NCW relationship. For the determination of initial liquefaction, the minimum curvature method, using the normalized cumulative stress (NCS)-normalized cumulative dissipated energy (NCW) curve, is proposed. The predicted initial liquefaction using the proposed method agrees well with the measured initial liquefaction. From results of additional undrained dynamic triaxial tests, the predicted EPP generation using the proposed model agrees well with the measured results for both sinusoidal and earthquake loading cases.