Failure mechanism analysis of tailing dams based on coupled discrete and continuous method

Based on the numerical results from the finite difference method (FDM), a representative local area is selected to conduct discrete-continuous coupling analysis using FDM and discrete element (DEM). The macro-scale and meso-scale mechanical responses of a tailing dam slope before and after filling are simulated by using the above model. The numerical results indicate that for the continuous domain, the results are almost the same using non-coupled method and coupled method. The meso-scale mechanical response in the slip bands, such as distribution of force chain and development of soil fabric, can be analyzed by using the discrete domain to discuss the meso-mechanism of failure of tailing dams. The research shows that in the formation of slip bands, the soil anisotropies in and out of the slip bands are obviously different: with the increasing load, soil particles in the potential slip bands have significant displacement. The main direction of stress has a significant rotation. The rotation of particles changes the fabric distribution, which contributes to the formation of slip bands and the slope instability. The main direction of stress of soil outside the bands rotates to some degree, while the shear stress changes little. The proposed discrete-continuous coupling method can analyze the meso-mechanism of formation of slip bands during slope progressive failure.