Effects of Suffusion on the Soil’s Mechanical Behavior: Experimental Investigations

Benahmed, Nadia; Nguyen, Cong Doan; Sibille, Luc; Philippe, Pierre

doi:10.1007/978-3-319-99423-9_1

Cited by 7 publications

(5 citation statements)

References 6 publications

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“…The study of suffusion using tomography being expensive and quite time consuming, the results presented in this paper concern an observation on a single experiment. Although only one sample was tested in the x-ray tomograph, the experiment carried out was repeated many times out of the tomograph with a good repeatability [35]. This suggests that the rather similar procedure adopted here in the tomography chamber is relevant and leads to the same type of microstructure evolution induced by suffusion.…”

Section: Suffusion Test With In-operando X-ray Tomographymentioning

confidence: 98%

Experimental investigation of microstructural changes in soils eroded by suffusion using X-ray tomography

et al. 2019

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Internal erosion is a complex phenomenon which represents one of the main risks to the safety of earthen hydraulic structures such as embankment dams, dikes or levees. Its occurrence may cause instability and failure of these structures with consequences that can be dramatic. The specific mode of erosion by suffusion is the one characterized by seepage flow induced erosion and the subsequent migration of the finest soil particles through the surrounding soil matrix mostly constituted of large grains. Such a phenomenon can lead to a modification of the initial microstructure and, hence, to a change in the physical, hydraulic and mechanical properties of the soil.A direct comparison of the mechanical behaviour of soil before and after erosion is often used to investigate the impact of internal erosion on soil strength (shear strength at peak and critical state) using triaxial tests.However, the obtained results are somehow contradictory, as for instance in Chang's study [1], where it is concluded that the drained strength of eroded soil decreases compared to non-eroded soil while both Xiao and Shwiyhat [2] and Ke and Takahashi [3] have come to the opposite conclusion. A plausible explanation of these contradictions might be attributed to the rather heterogeneous nature of the suffusion process and to the way the coarse and fine grains are rearranged afterwards leading to a heterogeneous soil structure, a point that, for now, is not taken into account, nor even mentioned, in the existing analyses.In the present study, x-ray computed tomography (x-ray CT) is used to follow the microstructure evolution of a granular soil during a suffusion test, and therefore, to capture the induced micro-structural changes. The images obtained from x-ray CT reveal indeed that fine particles erosion is obviously not homogeneous, highlighting the existence of preferential flow paths that lead to a heterogeneous sample in terms of fine particles, void ratio and inter-granular void ratio distribution.

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Section: Suffusion Test With In-operando X-ray Tomographymentioning

confidence: 98%

Experimental investigation of microstructural changes in soils eroded by suffusion using X-ray tomography

et al. 2019

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“…Aboul Hosn [54] performed flow-rate controlled downward erosion tests on gap-graded mixtures of coarse and fine silica Hostun sand in order to investigate the effects of the soil density on suffusion.…”

Section: Numerical Simulations Of Laboratory Testsmentioning

confidence: 99%

Modeling coupled erosion and filtration of fine particles in granular media

et al. 2019

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One of the major causes of instability in geotechnical structures such as dikes or earth dams is the phenomenon of suffusion including detachment, transport and filtration of fine particles by water flow. Current methods fail to capture all these aspects. This paper suggests a new modeling approach under the framework of the porous continuous medium theory. The detachment and transport of the fine particles are described by a mass exchange model between the solid and the fluid phases. The filtration is incorporated to simulate the filling of the intergrain voids created by the migration of the fluidized fine particles with the seepage flow and, thus, the self-filtration is coupled with the erosion process. The model is solved numerically using a finite difference method restricted to one-dimensional (1-D) flows normal to the free surface. The applicability of the model to capture the main features of both erosion and filtration during the suffusion process has been validated by simulating 1-D internal erosion tests and by comparing the numerical with the experimental results. Furthermore, the influence of the coupling between erosion and filtration has been highlighted, including the development of material heterogeneity induced by the combination of erosion and filtration.

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“…It is worth noting that suffusion is a complex phenomenon that comprises detachment, transport and potential filtration of fine particles, and none of the two above methods can fully represent the soil's micro-structure after suffusion. Aboul Hosn et al [8] freezed eroded samples after suffusion tests to set them in a triaxial device, and then unfreezed them before performing drained and undrained tests. The authors found that the eroded samples become more dilatant; however, their shear strength can be higher or lower than that of the non-eroded samples depending on their initial density.…”

Section: Introductionmentioning

confidence: 99%

“…If the water flow model is added to simulate the whole suffusion process including detachement, transport and filtration of finer particles, the computational cost becomes extremely high. Therefore, these coupled DEM-CFD models have been almost used to simulate only the onset of suffusion [1,9,10].…”

Section: Introductionmentioning

confidence: 99%

“…For the soils that exhibit important clogging effect, i.e., detached particles might be retained by the solid skeleton, the DEM needs to be coupled to a model to access filtration of erodible particles. For instance, according to Aboul-Hosn [1], a fine particle can be transported through the whole interstitial space of the solid skeleton and then can be removed from the sample if its diameter is smaller than the controlling constriction size of the solid skeleton. The latter parameter can be determined by using the constriction size distribution of the solid skeleton [16,23].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A DEM study of the effect of the loss of fine particles on the mechanical behavior of gap-graded soils

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Nguyen

Marot

et al. 2022

Geomechanics for Energy and the Environment

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Effects of Suffusion on the Soil’s Mechanical Behavior: Experimental Investigations

Cited by 7 publications

References 6 publications

Experimental investigation of microstructural changes in soils eroded by suffusion using X-ray tomography

Experimental investigation of microstructural changes in soils eroded by suffusion using X-ray tomography

Modeling coupled erosion and filtration of fine particles in granular media

A DEM study of the effect of the loss of fine particles on the mechanical behavior of gap-graded soils

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