Coupled particle-fluid simulations of the initiation of suffusion

Kawano, Kenji; Shire, Thomas; O’Sullivan, Catherine

doi:10.1016/j.sandf.2018.05.008

Cited by 48 publications

(21 citation statements)

References 29 publications

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“…For this kind of sample, the contribution of the weak network constituted by the fine-fine contacts decreased before turning point, while the contribution of the strong network constituted by the coarse-coarse/fine contacts increased, leading to a change in contribution of the overall strong and weak network to confining pressure. This is because in this phase, the fines with low connectivity and contact forces were eroded first, 15,16 resulting in stronger contact forces within the overall strong network.…”

Section: The Role Change Of Different Network During Suffusionmentioning

confidence: 99%

“…The decrease in the contact force between particles thus made the particles more vulnerable to detach. 53,15,29 Figure 16B shows the angle magnitude of the strong force chain in Figures 14 and 15. The angle magnitude (θ) is illustrated in the inset of Figure 16B.…”

Section: Strong Force Chain Bucklingmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] It was concluded from some studies that a higher confining F I G U R E 1 (A) Illustration of internal erosion and (B) schematic diagram of coarse grid DEM-CFD simulation approach adopted in this study pressure (p′) may help to prevent the occurrence of suffusion, due to the resulted increase in the interparticle contact force and particle connectivity. 8,9,15,16 Conversely, it was revealed from other studies that an increasing confining pressure could have intensified the suffusion (e.g., more fines loss) of a gap-graded soil. [1][2][3]5,60 The contradictory observations on the influences of p′ probably are resulted from the narrow scope of the influential factors (ie, p′ and F c ) considered in each study.…”

Section: Introductionmentioning

confidence: 97%

“…Researchers utilized a coarse-grid CFD-DEM, in which a fluid grid accommodates about 10 particles as shown in Figure 1B, to investigate the microscopic particle erosion and transport process within gap-graded soils. [15][16][17] Some researchers adopted a fine-grid CFD-DEM, where the fluid grid is much smaller than a particle and their interactions are directly computed by the commonly used immersed boundary method, to study fluid particle systems. 18 Recently, a coupled lattice Boltzmann method (LBM), which is an advanced high-resolution CFD solver for fluid flow and DEM approach, has been attracting substantial attention of researchers in geomechanics.…”

Section: Introductionmentioning

confidence: 99%

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A coupled CFD‐DEM investigation of suffusion of gap graded soil: Coupling effect of confining pressure and fines content

Liu

Wang

Hong

et al. 2020

Num Anal Meth Geomechanics

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Suffusion involves fine particles migration within the matrix of coarse fraction under seepage flow, which usually occurs in the gap-graded material of dams and levees. Key factors controlling the soil erodibility include confining pressure (p′) and fines content (F c), of which the coupling effect on suffusion still remains contradictory, as concluded from different studies considering narrow scope of these factors. For this reason, a systematical numerical simulation that considers a relative wide range of p′ and F c was performed with the coupled discrete element method and computational fluid dynamics approach. Two distinct macroresponses of soil suffusion to p′ were revealed, ie, for a given hydraulic gradient i = 2, an increase in p′ intensifies the suffusion of soil with fines overfilling the voids (eg, F c = 35%), but have negligible effects on the suffusion of gap-graded soil containing fines underfilling the voids (eg, F c = 20%). The micromechanical analyses, including force chain buckling and strain energy release, reveal that when the fines overfilled the voids between coarse particles (eg, F c = 35%) and participated heavily in load-bearing, the erosion of fines under high i could cause the collapse of the original force transmission structure. The release of higher strain energy within samples under higher p′ accelerated particle movement and intensified suffusion. Conversely, in the case where the fines underfilled the voids between coarse particles (eg, F c = 20%), the selective erosion of fines had little influence on the force network. High p′ in this case prevented suffusion.

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Section: The Role Change Of Different Network During Suffusionmentioning

confidence: 99%

Section: Strong Force Chain Bucklingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A coupled CFD‐DEM investigation of suffusion of gap graded soil: Coupling effect of confining pressure and fines content

Liu

Wang

Hong

et al. 2020

Num Anal Meth Geomechanics

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“…Two particle size distributions (PSDs) were considered, as illustrated in Figure 1, with FCs of 25% and 35%, corresponding to FC * and FC + respectively. These FC values were also considered in the coupled DEM-CFD (Computational Fluid Dynamics) simulations of Kawano et al [4] Three density values were considered for each FC, which was controlled by varying the coefficient of friction used during isotropic compression. In the current study, each sample was isotropically compressed to 100 kPa and then subjected to a constant p triaxial compression test using a servo-controlled algorithm as outlined in Thornton [5] and implemented in the LAMMPS code [6,7].…”

Section: Simulation Approachmentioning

confidence: 99%

Influence of stress anisotropy on stress distributions in gap-graded soils

et al. 2019

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The behaviour of gap graded soils comprising non-plastic fines (sand or silt) mixed with a coarser sand or gravel fraction has received attention from researchers interested in internal instability under seepage loading (a form of internal erosion) as well as researchers interested in load:deformation responses. Skempton and Brogan [1] postulated that resistance to seepage induced instability depends upon the proportion of the overall applied stress that is transmitted by the finer fraction. Shire et al. [2] explored Skempton and Brogan’s hypothesis using DEM simulations to look at the proportion of the applied stress transmitted by the finer fractions (α) in ideal isotropic samples. They showed that at low fines contents (FC< FC*) the average stress transmitted by the finer grains is less than the applied stress (α<1), while for FC>FC+ the fines play a key role in stress transmission (α>1); for FC*<FC< FC+, α depends on the sample density. The current contribution describes a series of constant p’ DEM triaxial test simulations carried out to assess the evolution of stress heterogeneity with shearing. The simulation data generated indicate that a sample can transition from being fines dominated (with the fines transmitting a significant proportion of the applied stress and α ≥1) to coarse or sand- dominated (with α <1) as the material dilates during shear deformation. While α reduces as the samples dilate, the relationship between the α and the sample void ratio is non-trivial. The anisotropy of the coarse-coarse contact network exceeds the overall contact force anisotropy; this indicates that the deviator stress is transmitted through a strong force network passing through the coarse-coarse contacts supported by the fine-coarse contacts.

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Influence of hydraulic and geometric conditions on the early stages of the filtration process in idealised granular soils comprising spherical particles

Zhang

Sufian

Scheuermann

2023

Num Anal Meth Geomechanics

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The early stages of particle‐scale filtration in idealised granular soils were investigated using coupled Computational Fluid Dynamics and Discrete Element Method. Filtration simulations were conducted for assemblies of finer base particles underlying coarser filter particles with upward seepage flow perpendicular to the base‐filter interface. A wide range of size ratios that covered the complete spectrum of filtration behaviours were considered, along with different ramping accelerations for seepage flow to investigate the combined influence of geometric characteristics and hydraulic loading. The influence of flow conditions and size ratios on the time‐dependent infiltration depth of transported base particles was observed to be universal with respect to a newly proposed dimensionless time parameter. The susceptibility to filtration during the early stages was quantitatively investigated with the number of infiltrating base particles and the filling degree of pores within the filter. The susceptibility during the early stages was shown to have a strong correlation with pore space geometry at the filter boundary, which was also reflected by the maximum pore filling degree of the filter. While filter susceptibility has been conventionally evaluated by the size ratio of the assembly, the consideration of the pore space geometry at the filter boundary provided an alternate approach of evaluating local filter susceptibility.

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Coupled particle-fluid simulations of the initiation of suffusion

Cited by 48 publications

References 29 publications

A coupled CFD‐DEM investigation of suffusion of gap graded soil: Coupling effect of confining pressure and fines content

A coupled CFD‐DEM investigation of suffusion of gap graded soil: Coupling effect of confining pressure and fines content

Influence of stress anisotropy on stress distributions in gap-graded soils

Influence of hydraulic and geometric conditions on the early stages of the filtration process in idealised granular soils comprising spherical particles

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