Dynamic Properties of Spatially-Varied Pond Ash within a Coal Ash Pond

Abstract

Abandoned ash pond beds have been considered for their reclamation through the construction of lightweight structures. Under static conditions, an ash pond bed can sustain these structures but its stability must be ascertained under seismic conditions. This paper presents the results of geotechnical characterization and dynamic properties of pond ash samples that were collected from three different locations ranging from the inflow point to the outflow point of the ash pond of the Ropar thermal power plant (India). Strain-controlled cyclic triaxial tests were conducted on collected samples, considering the effect of various parameters, such as shear-strain amplitude, confining pressure, frequency, and density. The shear modulus of the coarser pond ash sample near the inflow was observed to be greater than that of the finer pond ash near the outflow. The shear-strain amplitude and frequency of cyclic loading increases with a decrease in the shear modulus. The damping ratio is greater in the case of finer ash. Moreover, damping ratio increases with an increase in strain amplitude and frequency of loading. The dynamic behavior of the pond ash sample was also compared with that of sand. The area near the inflow of the ash pond, where there is coarser ash was found to be more suitable for reclamation of the ash pond bed under seismic conditions.