A three-dimensional model for flow slides in municipal solid waste landfills using smoothed particle hydrodynamics

Flow slides at municipal solid waste (MSW) landfills can lead to a leak of toxic MSW and leachate over a large area, and result in serious pollution to the environment in the surrounding region. It is therefore important to predict the propagation of failed MSW in the environment, and then take protective measures. In this paper, a three-dimensional (3D) model based on the smoothed particle hydrodynamics method, which is an improved version of the previous two-dimensional (2D) model (Huang et al. in Waste Manag Res 31(3):256–264, 2013), is established to reproduce the propagation stage of the failed MSW across complex terrain. The Navier–Stokes equations and Bingham model are adopted as the governing equations and constitutive model, respectively. A no-slip boundary condition is incorporated to consider the effect of a solid boundary on the MSW movement. The 3D performance of the new model is verified and evaluated through the simulation of a MSW flow model test. The established 3D model and the former 2D model are applied to simulate a typical flow slide that occurred at the Ümraniye-Hekimbasi landfill. The final shape of the waste deposit simulated with the 3D model well matches the field observation; the performance of the new model in simulating flow slides for MSW in three dimensions across complex terrain is highlighted. The presented model can play a role in defining and mapping hazardous areas, and provide a means for the identification and design of appropriate protective measures for landfills with potential flow slides.