Visualisation of seepage-induced suffusion and suffosion within internally erodible granular media

Hunter, Robert Peter; Bowman, Elisabeth T.

doi:10.1680/jgeot.17.p.161

Cited by 60 publications

(31 citation statements)

References 17 publications

(45 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The suffusion results in literature give generally a macroscopic point of view and the evolution of soil microstructure (the scale of the soil's induced heterogeneities) usually is not explicitly mentioned in the existing analysis. In addition to the present work, only few and very recent visualisations and analyses of suffusion at grain scale can be mentioned in the literature, either by Hunter & Bowman based on optical techniques [3], or by Mehdizadeh & Disfani based on X-ray tomography [2].…”

Section: Introductionmentioning

confidence: 97%

Soil microstructural changes induced by suffusion: x-ray computed tomography characterization

Nguyen¹,

Benahmed

Andò

et al. 2019

E3S Web Conf.

View full text Add to dashboard Cite

Suffusion is one mechanism of internal erosion, which occurs in gap-graded or broadly graded soils when the fine particles are detached and transported by the seepage flow through the void space formed by the granular soil skeleton. Suffusion is therefore a particle scale mechanism. During this microscale, the initial soil fabric may change due to both fines migration and coarse grains rearrangement, leading to an increase/decrease of global/local porosity and hydraulic conductivity, besides of a probable appearance of heterogeneity, which can, in turn, impact the mechanical behaviour of the eroded soil. In the literature, suffusion test results give only a macroscopic point of view and fail to quantify the effect of suffusion at the scale of the soil's induced heterogeneities. In this paper, x-ray tomography is used to get microscopic observations of soil sample microstructure evolution during a suffusion test. The results reveal that suffusion is not a homogeneous process; the removal of fine particles takes place mainly around the soil sample circumference leading to a higher void ratio at the periphery. Besides, the inter-granular void ratio decreases significantly but almost uniformly throughout the sample owing to the progressive collapse and reorganization of the coarse grains induced by the loss in fines.

show abstract

Section: Introductionmentioning

confidence: 97%

Soil microstructural changes induced by suffusion: x-ray computed tomography characterization

Nguyen¹,

Benahmed

Andò

et al. 2019

E3S Web Conf.

View full text Add to dashboard Cite

show abstract

“…Clays treated with NaCl solution, when exposed to distilled water, see their residual shear strength decrease; this was observed in bentonite (Di Maio & Fenelli, 1994;Di Maio, 1996;Di Maio & Scaringi, 2016), illitic soils (Di Maio et al, 2015) and mudstone soil from Japan (Tiwari et al, 2005, Tiwari & Ajmera, 2015. When seepage occurs, not only will the pore solution concentration change, but the fine particles may move through the soil matrix by suffusion, resulting in the soil internal instability (Fannin & Slangen, 2014;Hunter & Bowman, 2018).…”

Section: Introductionmentioning

confidence: 99%

The structure degradation of a silty loess induced by long-term water seepage

Zuo

Baudet

et al. 2020

Engineering Geology

View full text Add to dashboard Cite

Loess is a typical silt-sized Aeolian soil that is widely deposited and possesses a fragile soil structure susceptible to collapse upon wetting. The instability of shallow loess slopes is well documented, but deeper failures triggered by rainfall and irrigation can also occur. In the case of long-term seepage, clay particles and salts have been observed to leach out of the loess slopes. This paper presents a systematic laboratory study of the effects of water conditions on the mechanical behaviour of silty loess, with isotropic compression and bender element tests carried out on natural and reconstituted loess recovered at 10m depth from a site in China. The results show that saturation causes reduction in both the compression yield stress and small strain stiffness of the soil, and that after being exposed to seepage, they decrease further.The possible mechanism of structure degradation is investigated by means of microscopic and chemical analyses, and it is found that seepage will cause the pore ions concentration to reduce with a loss of clay mineral bonding strength, resulting in the detachment of silt particles from aggregates. This work highlights the importance of monitoring the water outflow in the field at the loess slope edge, since it may causes large deformation in the long-term.

show abstract

“…The finer sand loss serves as a directly observed and evaluated parameter in experimental and numerical modelling of suffusion development (Chen, Zhang, Lei, et al, 2012;Hu et al, 2019;Ke & Takahashi, 2012;Nguyen et al, 2019). When the critical hydraulic gradient for internal erosion is reached, small dance-like movements of finer particles occur (Hunter & Bowman, 2018;Ke & Takahashi, 2012). Then, strong suffusion initiates throughout the sample, and finer particles migrate up through the sample, whereas larger particles can hardly be moved unless the hydraulic load has enough power and the soil structure has enough void.…”

Section: Introductionmentioning

confidence: 99%

A theoretical model to predict suffusion‐induced particle movement in cohesionless soil under seepage flow

Huang

Bai

et al. 2020

European J Soil Science

View full text Add to dashboard Cite

Suffusion is a grave threat leading to accidents in embankment dams across the world. The process has been widely studied experimentally and numerically with gap‐grading cohesionless soil. One of the direct observations in the studies is the finer particle loss of the soil. However, the movement of the finer particles in the numerical models is commonly predicted with an empirical law. This paper proposes a theoretical particle movement model based on the force balance of soil particles and a probability distribution of the soil pores under one‐dimensional upward seepage flow. In the proposed model, the velocity and the critical movement state of soil particles were deduced, and a method to predict the critical hydraulic gradient was established. The finer particle movement rate was estimated theoretically using the particle movement velocity and probability. The model was verified with several experiments and showed a good consistency in the critical hydraulic gradient, seepage velocity, finer particle loss and hydraulic conductivity. Finally, the changes in the soil parameter during the suffusion process, the effects of the hydraulic gradient and initial porosity and the model applicability are discussed quantitatively. The results indicate that the modelled soil parameter changes match well with the movement characteristics of the finer particles observed in the experiment. The particle movement process is very sensitive to changes in the hydraulic gradient and soil initial porosity. The theoretical model provides a new method to assess the suffusion process for internal unstable cohesionless sand soil.Highlights A evaluation model of the suffusion‐induced soil particle movement was proposed The model was established based on force equilibrium of soil particles The model was credible in varied factors based on experiment data The model evaluated suffusion process, variables affects and model applicability were discussed

show abstract

Visualisation of seepage-induced suffusion and suffosion within internally erodible granular media

Cited by 60 publications

References 17 publications

Soil microstructural changes induced by suffusion: x-ray computed tomography characterization

Soil microstructural changes induced by suffusion: x-ray computed tomography characterization

The structure degradation of a silty loess induced by long-term water seepage

A theoretical model to predict suffusion‐induced particle movement in cohesionless soil under seepage flow

Contact Info

Product

Resources

About