Simulation on mechanical behavior of cohesive soil by Distinct Element Method

Zhang, Rui; Li, Jianqiao

doi:10.1016/j.jterra.2005.05.006

Cited by 79 publications

(39 citation statements)

References 6 publications

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“…The next logical step would be to include cohesion. Cohesion can be added to a dem model in the form of inter-particle bonds [30]. The strength and stiffness of these bonds can be based on the capillary and dynamic viscous forces induced by the presence of water between soil particles.…”

Section: Resultsmentioning

confidence: 99%

Discrete and continuum modelling of soil cutting

Coetzee

2014

Comp. Part. Mech.

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Both continuum and discrete methods are used to investigate the soil cutting process. The Discrete Element Method (dem) is used for the discrete modelling and the Material-Point Method (mpm) is used for continuum modelling. Mpmis a so-called particle method or meshless finite element method. Standard finite element methods have difficulty in modelling the entire cutting process due to large displacements and deformation of the mesh. The use of meshless methods overcomes this problem. Mpm can model large deformations, frictional contact at the soil-tool interface, and dynamic effects (inertia forces). In granular materials the discreteness of the system is often important and rotational degrees of freedom are active, which might require enhanced theoretical approaches like polar continua. In polar continuum theories, the material points are considered to possess orientations. A material point has three degrees-of-freedom for rigid rotations, in addition to the three classic translational degrees-of-freedom. The Cosserat continuum is the most transparent and straightforward extension of the nonpolar (classic) continuum. Two-dimensional dem and mpm (polar and nonpolar) simulations of the cutting problem are compared to experiments. The drag force and flow patterns are compared using cohesionless corn grains as material. The corn macro (continuum) and micro (dem) properties were obtained from shear and oedometer tests. Results show that the dilatancy angle plays a significant role in the flow of material but has less of an influence on the draft force. Nonpolar mpm is the most accurate in predicting blade forces, blade-soil interface stresses and the position and orientation of shear bands. Polar mpm fails in predicting the orientation of the shear band, but is less sensitive to mesh size and mesh ori-C. J. Coetzee (B) Department of Mechanical and Mechatronic Engineering, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa e-mail: ccoetzee@sun.ac.za entation compared to nonpolar mpm. dem simulations show less material dilation than observed during experiments.

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Section: Resultsmentioning

confidence: 99%

Discrete and continuum modelling of soil cutting

Coetzee

2014

Comp. Part. Mech.

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“…In the figure, soil swelling is defined difference between initial height of the soil and maximum height during shearing. The elevation of each model increased with the blade displacement, and the highest elevation was seen in model (4). Compared with the porosity change obtained from the compression simulation in Section 3.2.1, this tendency, which has large elevation when shearing in the model, is shown when the porosity change is large.…”

Section: Journal Of System Design and Dynamicsmentioning

confidence: 70%

“…Once the compressed soil model was shorn, the close soil starts collapsing and returns to its original state before compression. Therefore, the elevation by shearing is small in models (1) and (5) in which the porosity changes were small, and it is the largest in model (4) in which the porosity changes were the largest. Thus, this soil model that considered particle roughness expressed the actual soil elevation compared with the traditional model; the effectiveness of the soil model was confirmed.…”

Section: Journal Of System Design and Dynamicsmentioning

confidence: 95%

“…In addition, the porosity changes of models (1) and (5) before and after compression are smaller than those of other models, showing that no small particle enters the space by compression because model (1) only consists of the particle cluster and model (5) is already close before it is compressed because of the traditional equal particle radius model. Comparing models (2) to (4), the porosity change was largest in model (4). Many single particles entered the space by compression, because model (4) has the highest ratio of single particles in models (1) to (4) including the particle cluster.…”

Section: Soil Compressionmentioning

confidence: 97%

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Analysis of Interaction between Grouser and Soil Using Distinct Element Method (DEM)

Koizumi

Tsujiuchi

Akatsuka

2010

JSDD

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When signing for tracked vehicles, which are operated on unpaved roads or soft ground, the interaction between machine and soil must be analyzed. In this research, attention was focused on the interaction under front idler, that is, traction soil by a grouser in driving system. To verify the validity of interaction analysis between a grouser and soil by using 3D DEM soil model, traction simulations and experiments were carried out. In addition, the soil model was considered particle roughness to introduce compaction effect by compression. To check the effectiveness of the soil model, compression test and shearing test were conducted. Consequently, soil behavior and porosity change were found on the tests. And comparing the results of traction simulations and experiments, soil behavior and qualitative characteristics of traction resistance were conformed. Therefore, interaction between grouser and soil could be analyzed by using the soil model considering particle roughness.

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“…More sophisticated models couple the mechanical behavior of the DEM with the solution of the Navier-Stokes equation [11] * s.galindotorres@uq.edu.au to study the liquefaction of saturated soils. Other models include the capillary interaction that may bind the grains under unsaturated conditions [12]. Recently, the DEM has been coupled with the lattice Boltzmann model for fluids to fully couple the mechanical behavior of fluids and solids [13], which is a promising technique with the potential to describe a wide range of phenomena in saturated and unsaturated conditions.…”

Section: Introductionmentioning

confidence: 99%

Effect of frictional heat dissipation on the loss of soil strength

Galindo‐Torres

Lizcano²,

Muñoz

2012

Phys. Rev. E

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In the present paper through a shear test on a fully saturated granular medium, simulated by the discrete element method, the effect of the heat produced by friction on the internal pore water pressure is explored. It is found that the dissipated energy is enough to increase the pore pressure and reduce the soil strength. In adiabatic and impermeable conditions the heat builds up quickly inside the shear band, and the softening is more pronounced. It is found as well that for real geological materials, heat conduction is not enough to reduce the pore pressure, and the softening prevails. Nevertheless, it is observed that the hydraulic conduction may mitigate or completely eliminate the temperature growth inside the shear band. This result provides new understanding on the thermodynamic factors involved in the onset of catastrophic landslides.

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Simulation on mechanical behavior of cohesive soil by Distinct Element Method

Cited by 79 publications

References 6 publications

Discrete and continuum modelling of soil cutting

Discrete and continuum modelling of soil cutting

Analysis of Interaction between Grouser and Soil Using Distinct Element Method (DEM)

Effect of frictional heat dissipation on the loss of soil strength

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