A CFD–DEM study on the suffusion and shear behaviors of gap-graded soils under stress anisotropy

Hu, Zheng; Li, J. Z.; Zhang, Yida; Yang, Z. X.; Liu, J. K.

doi:10.1007/s11440-022-01755-7

Cited by 21 publications

(5 citation statements)

References 77 publications

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“…In view of the above problems, this study aimed to investigate the effect of specimen length on suffusion and to explore its underlying physical mechanisms. We employed the coupled computational fluid dynamics-discrete element method (CFD-DEM), which has been extensively adopted for suffusion research [40,44,45]. It enables the capture of particle motion and micromechanical evolution, which are challenging to observe in experiments.…”

Section: 𝑅 mentioning

confidence: 99%

“…In the validation case, the walls of the DEM domain were fixed to reproduce the experimental setup of Yin et al [24]. However, various studies have shown that stress conditions are one of the key criteria for suffusion to occur and cannot be ignored [44,54,55]. Accordingly, in the subsequent cases, the walls of the DEM were modelled as servo walls to account for the effect of stress conditions.…”

Section: Validationmentioning

confidence: 99%

“…During the consolidation process, the strain of the specimen was continuously monitored until stabilization was achieved, indicating completion of consolidation. Subsequently, a hydraulic gradient was applied and the top wall was replaced with a permeable wall [44] that allowed the passage of fine particles. The suffusion process was initiated and allowed to proceed for a duration of 20 s, during which a constant confining pressure was maintained.…”

Section: Simulation Programmentioning

confidence: 99%

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Investigation on the mechanism of size effect on suffusion via CFD-DEM simulations

Zhu,

Hu,

et al. 2023

Preprint

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Suffusion is a critical issue in geotechnical engineering. Despite extensive studies, the effect of soil specimen dimensions on suffusion remains unclear. In this paper, a coupled computational fluid dynamics and discrete element method (CFD-DEM) approach is employed to study the suffusion of gap-graded soils with varying aspect ratios, and the underlying physical mechanisms are discussed. The results indicate that as the aspect ratio increases, erosion degree, mechanical coordination numbers, and unevenness in the fines distribution decrease, while the likelihood of fine particles integrating into the soil skeleton rises. Before suffusion, specimens with lower aspect ratios show higher peak strengths. After suffusion, peak strength decreases with erosion degree. However, all specimens exhibit comparable residual strengths. The mechanism behind different suffusion behaviors in specimens with varying aspect ratios is primarily governed by their unique suffusion boundary conditions. Accounting for suffusion boundaries significantly modify erosion laws and eroded soil mechanics behaviors. A standardized specimen size is proposed to account for suffusion boundary effects, thereby minimizing errors attributed to variations in outlet sieve aperture sizes and inconsistencies in specimen dimensions. The results obtained highlight the influence of specimen size on suffusion, advancing our precise understanding of eroded soil behavior and furthering the development of phenomenological constitutive models.

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Section: 𝑅 mentioning

confidence: 99%

Section: Validationmentioning

confidence: 99%

Section: Simulation Programmentioning

confidence: 99%

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Investigation on the mechanism of size effect on suffusion via CFD-DEM simulations

Zhu,

Hu,

et al. 2023

Preprint

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“…Among them, the DEM method is the most widely used method for the simulation of soil. For the soil seepage erosion problem, the DEM-based fluid-solid coupling model has been chosen by many researchers to carry out micro-mechanism studies, and to discuss the influence of different factors on the erosion process, such as particle shape [13,14], particle size distribution [15][16][17], soil stress [18][19][20], clogging effect [21], and so on. For the problem of discontinuous large deformation induced by seepage erosion of soil, the DEM-based coupled fluid-solid analysis method also has relevant applications.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation on the Leakage-Induced Collapse of Segmental Tunnels

Sun,

Liu,

De Corte

et al. 2024

Applied Sciences

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Sudden leakage during tunnel construction poses a great threat to the safety of the tunnel. There are relatively few studies on the mechanism of structural collapse induced by tunnel leakage, so it is difficult to propose effective control measures. To solve this problem, a coupled fluid–solid strata analysis model and a nonlinear FEM tunnel model were established based on model test results to analyze the mechanism of tunnel collapse. The following conclusions were drawn: (1) A DEM-based coupled fluid–solid model combined with a nonlinear FEM tunnel model can effectively simulate the physical process of tunnel collapse. (2) The mechanism of tunnel leakage-induced strata response is the continuous destabilization and reappearance of the soil arching effect, which restricts the erosion of the soil and results in macroscopic soil caves, and finally leads to the impact load of the destabilized soil. (3) The process of the tunnel structure collapse is as follows: firstly, a large deformation of the tunnel structure is caused by the redistribution of external loads generated by the earth arching effect; then, due to the multiple impact loads from the destabilization of the soil, plastic hinges are generated at the tunnel joints, and the tunnel collapses.

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“…Zhao et al [25] and Shan et al [26] investigated the formation process of underwater sand piles and the evolution mechanism of landslides in reservoir areas. Hu et al [27] studied the effect of an anisotropic stress state on the seepage erosion of gap-graded sand under various average stresses. Liu et al [28] investigated the macroscopic and microscopic evolutions of discontinuous graded sand under three-dimensional coupling in various flow directions under anisotropic conditions, considering that the mean effective stress p ′ considerably influences the evolutionary pattern of suffusion and mechanical response in gap-graded soil.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Consequences of Suffusion on Gap-Graded Soils with Stress Anisotropy: A CFD–DEM Perspective

Yu,

et al. 2024

Buildings

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Natural soil in geotechnical engineering is commonly in the anisotropic stress state, but the effect of stress anisotropy on soil suffusion remains unclear. In this study, the coupled computational fluid dynamics–discrete element method was utilised to simulate the complete suffusion process of gap-graded soils by introducing a vertical seepage flow through the soil assembly. The mechanical consequences of suffusion on gap-graded soils were evaluated by comparing the triaxial shear responses of soil specimens before and after suffusion. The results indicated that the specimens with greater stress anisotropy are more vulnerable to suffusion, particularly those with the principal stress that is coincident with the principal flow direction. Compared with the isotropically consolidated specimens, the specimens with greater stress anisotropy exhibited more pronounced reduction in shear strength and secant stiffness after suffusion. The effects of stress anisotropy on the suffusion and mechanical properties of gap-graded soils were also evaluated from a microcosmic perspective in terms of force chain, coordination number, and fabric tensor.

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A CFD–DEM study on the suffusion and shear behaviors of gap-graded soils under stress anisotropy

Cited by 21 publications

References 77 publications

Investigation on the mechanism of size effect on suffusion via CFD-DEM simulations

Investigation on the mechanism of size effect on suffusion via CFD-DEM simulations

Numerical Simulation on the Leakage-Induced Collapse of Segmental Tunnels

Mechanical Consequences of Suffusion on Gap-Graded Soils with Stress Anisotropy: A CFD–DEM Perspective

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