Probabilistic Investigation on Bearing Capacity of Unsaturated Fly Ash

The utilization of coal combustion residue waste generated by thermal power plants, such as fly ash, as a sustainable geomaterial in an efficient manner might reduce the hazard posed by it. A promising solution might be the bulk use of fly ash as fill material in geotechnical engineering projects. However, the bearing capacity of fly ash deposits, taking into consideration the unsaturated behavior has rarely been investigated. This necessitates the evaluation of the effects of water retention characteristics curve (WRCC) parameters and infiltration rate ratio in combination with the strength parameter on the bearing capacity of an unsaturated fly ash deposit. This study investigates the effects of these parameters on the bearing capacity of fly ash deposits through nonlinear finite element (FE) analyses. A probabilistic investigation is presented for determining the relative influences of these parameters on the bearing capacity and settlement considering the uncertainty of these parameters. This study indicates that the bearing capacity of the unsaturated fly ash deposit is significantly influenced by infiltration conditions in combination with the strength parameter. Prediction equations are framed for the bearing capacity and settlement of an unsaturated fly ash deposit considering variations of these parameters. The probability of failure of a strip footing on a fly ash deposit is then evaluated using the Monte Carlo (MC) simulation techniques for the developed prediction models.