Calibration of prediction models for excess pore water pressure generation in pond ash

This experimental study calibrated the prediction models for the excess pore water pressure response of different pond ash samples under cyclic loading. A total of 63 stress-controlled cyclic simple shear tests were performed on pond ash samples with varying particle size gradation at different overburden pressures and cyclic stress ratios (CSR). The excess pore water pressure response of pond ash under cyclic loading was calibrated by the models available for clean sand and sand-silt mixtures, along with statistical analysis. Two prediction models were selected based on the previous studies on natural cohesionless soil with different gradations. The response of excess pore water pressure generation in pond ash followed different models for specimens with N<inf>L</inf> ≥ 22 and N<inf>L</inf> < 22, respectively. The selected models accurately predicted the excess pore water pressure response of all pond ash specimens as very high Coefficient of determination (R²) and very low root mean square error (RMSE) values, and shorter Confidence Intervals (CI) were observed when calibrating the experimental data. The calibration parameter showed notable alterations with the change in particle size gradation, CSR and overburden pressure.