Modelling Transient Dynamics of Granular Slopes: MPM and DEM

Abstract

1st International Conference on the Material Point Method MPM 2017Transient granular flows, such as rock falls, debris flows, and aerial and submarine avalanches, occur very often in nature. In the geotechnical context, transient movements of large granular slopes are a substantial factor of risk due to their destructive force and the transformations they may produce in the landscape. This paper investigates the ability of MPM, a continuum approach, to reproduce the evolution of a granular slope destabilised by an external energy source. In particular, a central issue is whether the power-law dependence of run-out distance and time observed with respect to the initial geometry or energy can be reproduced by a simple Mohr-Coulomb plastic behaviour. The effect of base friction on the run-out kinematics is studied by comparing the data obtained from the DEM and MPM simulations. The mechanism of energy dissipation is primarily through friction and the MPM is able to predict the run-out response in good agreement with the DEM simulations. At very low excitation energies, the DEM simulations show longer run-out in comparison to the MPM due to local destabilization at the flow front. At low input energies, a larger fraction of the energy is consumed in the destabilisation process, hence the amount energy available for flow is less. However, at higher input energy, where most of the energy is dissipated during the spreading phase, the run-out distance has a weak dependence on the distribution of velocity in the granular mas

An improved convected particle domain interpolation material point method for large deformation geotechnical problems

“…Finally, the topology parameters r t+Δt 1 ,r t+𝛥t 2 and the positions of the material point domain corners x t+Δt cj (j = 1, 2, 3, 4) are updated using Equations (36) and (37). The velocity of material point domain corners v t+Δt cj (j = 1, 2, 3, 4) is updated by Equation (40).…”

“…[16][17][18][19][20][21] The MPM incorporates the advantages of Lagrangian and Eulerian methods, which avoids grid distortion problems and can model history-dependent material behavior. 22 The MPM is an effective method for dealing with large-deformation problems and has been successfully employed in a variety of engineering applications, including solid mechanics, 23,24 solid-fluid interaction problems, [25][26][27][28][29][30][31][32][33] incompressible material flows, 34,35 granular flows, 36,37 dike failure, 29,38,39 and graphics research. 40,41 However, MPM suffers from numerical artifact noise and cell-crossing errors when the material points cross the grid boundaries.…”

A Study on the Unstable Evolution Characteristics of Loose Particle Slopes under Dynamic Supply of Material Sources

“…The main issues studied are the factors affecting the stability of bulk slope, the effect of earthquakes on the morphology of bulk slope, the prevention and control measures, and the characteristics of bulk slope stacking evolution. Texier et al [8][9][10][11][12][13] investigated the effects of natural angle of repose, particle gradation distribution, particle size, water content, particle roundness, particle gradation and other factors on bulk slope stability. Fan Limin et al 14 obtained through theoretical analysis that the main factors affecting the runoff flow rate at the surface of the slope and the seepage flow rate inside the slope body are slope gradient, runoff water depth, porosity and permeability of the bulk granular body of the slope, and the flow rate increases with its increase Marchelli, M. et al 9,10,[15][16][17][18][19][20][21] conducted a study on the preventive and curative measures against disasters of the bulk granular slopesretaining walls, slit dams, and detention barriers.…”

Experimental Methods in Chemical Engineering: Discrete Element Method—DEM

“…Families of numerical models to study granular flows include: Continuum‐based approaches such as two‐fluid, level‐set, particle finite element or material point methods; Cellular automata; Monte‐Carlo methods; Discrete element methods (DEM) such as soft‐sphere, impulse‐based (iDEM), extended (XDEM), non‐smooth (NDEM), or coarse‐grained (CGDEM) discrete element methods; and Hybrid methods such as the combined finite‐discrete element method …”

“…Continuum‐based approaches such as two‐fluid, level‐set, particle finite element or material point methods;…”