Numerical Simulation of Subdam Settlement in Ash Disposal Based on CGSW Optimization

Abstract

The stacking of impermissible materials in the disposal of dry fly ash is unprecedented in the last 40 years of power plant management in China, and their effect on the stability of the whole facility is uncertain. Due to the lack of relevant treatment experience, a more comprehensive method such as numerical modeling must be adopted for the final design. This paper set up a borehole database from geological logging data to obtain the distribution of the coal gangue solid waste. Then, it established an accurate three-dimensional mesh model through Rhino. Based on elastic–plastic mechanics, the finite difference code Flac3D 6.0 was employed to study the risk of the coal gangue as a dam foundation. A comparative analysis of the influence of the displacement method and the composite foundation method on subdam deformation and differential subsidence was conducted. The simulation revealed that the composite foundation method showed the best reductions: 70.57% in shear failure, 97.83% in tension failure, and 22.63% in maximum subsidence. Ultimately, the optimum stone column diameter of 0.5 m and the spacing of 6 m were proposed due to the standard deviation.