Equations for hydraulic conductivity estimation from particle size distribution: A dimensional analysis

Wang, Jipeng; Baudin, François; Lambert, Pierre

doi:10.1002/2017wr020888

Cited by 64 publications

(38 citation statements)

References 16 publications

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“…Normally, unsaturated hydraulic conductivity is regarded as a parameter associated with its saturated hydraulic conductivity and the soil water retention curve (WRC, the relationship between suction and degree of saturation) [1][2][3]. For sandy soils, it is also widely accepted that using grain size distribution parameters can estimate its saturated hydraulic conductivity [4][5][6][7][8] and water retention curve [9][10][11][12]. Therefore, the unsaturated conductivity properties of sandy soils may also be primarily predicted from their particle size distributions.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, the unsaturated conductivity properties of sandy soils may also be primarily predicted from their particle size distributions. The recent work of Wang et al [8,12] can be extended for estimating unsaturated conductivity properties, for example, the relative permeability.…”

Section: Introductionmentioning

confidence: 99%

“…By using the dimensional analysis method and combining with regression analysis on a database, Wang's model [8] has been developed to predict hydraulic conductivity values of saturated sandy soils from grain size parameters. The method shows the best prediction accuracy among the classic methods.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Estimation of Unsaturated Hydraulic Conductivity of Granular Soils from Particle Size Parameters

Wang

Zhuang

Luan

et al. 2019

Water

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Estimation of unsaturated hydraulic conductivity could benefit many engineering or research problems such as water flow in the vadose zone, unsaturated seepage and capillary barriers for underground waste isolation. The unsaturated hydraulic conductivity of a soil is related to its saturated hydraulic conductivity value as well as its water retention behaviour. By following the first author's previous work, the saturated hydraulic conductivity and water retention curve (WRC) of sandy soils can be estimated from their basic gradation parameters. In this paper, we further suggest the applicable range of the estimation method is for soils with d 10 > 0.02 mm and C u < 20, in which d 10 is the grain diameter corresponding to 10% passing and C u is the coefficient of uniformity (C u = d 60 /d 10 ). The estimation method is also modified to consider the porosity variation effect. Then the proposed method is applied to predict unsaturated hydraulic conductivity properties of different sandy soils and also compared with laboratory and field test results. The comparison shows that the newly developed estimation method, which predicts the relative permeability of unsaturated sands from basic grain size parameters and porosity, generally has a fair agreement with measured data. It also indicates that the air-entry value is mainly relative to the mean grain size and porosity value change from the intrinsic value. The rate of permeability decline with suction is mainly associated with grain size polydispersity.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Estimation of Unsaturated Hydraulic Conductivity of Granular Soils from Particle Size Parameters

Wang

Zhuang

Luan

et al. 2019

Water

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“…Considering the soil composition, the block of terrain can be characterized by porosity, φ, an effective porosity, φ e and saturation permeability. The latter can be evaluated indirectly using the Koseny-Carman equation [31,32] and the granulometric curve of the soil [32,33]:…”

Section: The Terrain Water-balance Modelmentioning

confidence: 99%

Wildfire Impacts on Slope Stability Triggering in Mountain Areas

et al. 2019

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Landslides over steep slopes, floods along rivers plains and debris flows across valleys are hydrogeological phenomena typical for mountain regions. Such events are generally triggered by rainfall, which can have large variability in terms of both its intensity and volume. Furthermore, terrain predisposition and the presence of some disturbances, such as wildfires, can have an adverse effect on the potential risk. Modelling the complex interaction between these components is not a simple task and cannot always be carried out using instability thresholds that only take into account the characteristics of the rainfall events. In some particular cases, external factors can modify the existing delicate equilibrium on the basis of which stability thresholds are defined. In particular, events such as wildfires can cause the removal of vegetation coverage and the modification of the soil terrain properties. Therefore, wildfires can effectively reduce the infiltration capacity of the terrain and modify evapotranspiration. As a result, key factors for slope stability, such as the trend of the degree of saturation of the terrain, can be strongly modified. Thus, studying the role of wildfire effects on the terrain's hydrological balance is fundamental to establish the critical conditions that can trigger potential slope failures (i.e., shallow landslides and possible subsequent debris flows). In this work, we investigate the consequences of wildfire on the stability of slopes through a hydrological model that takes into account the wildfire effects and compare the results to the current stability thresholds. Two case studies in the Ardenno (IT) and Ronco sopra Ascona (CH) municipalities were chosen for model testing. The aim of this paper is to propose a quantitative analysis of the two cases studies, taking into account the role of fire in the slope stability assessment. The results indicate how the post-fire circumstances strongly modify the ability of the terrain to absorb rainfall water. This effect results in a persistently drier terrain until a corner point is reached, after which the stability of the slope could be undermined by a rainfall event of negligible intensity.

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“…Wang et al 2017 [24] analyzed the relationship between hydraulic conductivity and PSD. The grain diameter at 10% passing ( 10 ) was regarded in porosity effect.…”

Section: Prediction Of Hydraulic Properties Evolutionmentioning

confidence: 99%

Experimental Investigation on Hydraulic Properties of Granular Sandstone and Mudstone Mixtures

Cai

Zhou

et al. 2018

Geofluids

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The caved zone during longwall mining has high permeability, resulting in a mass of groundwater storage which causes a threat of groundwater inrush hazard to the safe mining. To investigate the hazard mechanism of granular sandstone and mudstone mixture (SMM) in caved zone, this paper presents an experimental study on the effect of sandstone particle (SP) and mudstone particle (MP) weight ratio on the non-Darcy hydraulic properties evolution. A self-designed granular rock seepage experimental equipment has been applied to conduct the experiments. The variation of particle size distribution was induced by loading and water seepage during the test, which indicated that the particle crushing and erosion properties of mudstone were higher than those of sandstone. Porosity evolution of SMM was strongly influenced by loading (sample height) and SP/MP weight ratio. The sample with higher sample height and higher weight ratio of SP achieved higher porosity value. In particular, a non-Darcy equation, for hydraulic properties (permeability and non-Darcy coefficient ) calculation, was sufficient to fit the relation between the hydraulic gradient and seepage velocity. The test results indicated that, due to the absence and narrowing of fracture and void during loading, the permeability decreases and the non-Darcy coefficient increases. The variation of the hydraulic properties of the sample within the same particle size and SP/MP weight ratio indicated that groundwater inrush hazard showed a higher probability of occurrence in sandstone strata and crushed zone (e.g., faults). Moreover, isolated fractures and voids were able to achieve the changeover from self-extension to interconnection at the last loading stage, which caused the fluctuation tendency of and . Fluctuation ability in mudstone was higher than that in sandstone. The performance of an empirical model was also investigated for the non-Darcy hydraulic properties evolution prediction of crushing and seepage processes. The predictive results indicated that particle crushing and water erosion caused the increase of hydraulic properties, being the main reason that the experimental values are typically higher than those obtained from the predictive model. The empirical model has a high degree of predictive accuracy; however, has a higher predictive accuracy than . Furthermore, the predictive accuracy of increases and decreases with increasing weight ratio of SP.

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Equations for hydraulic conductivity estimation from particle size distribution: A dimensional analysis

Cited by 64 publications

References 16 publications

Estimation of Unsaturated Hydraulic Conductivity of Granular Soils from Particle Size Parameters

Estimation of Unsaturated Hydraulic Conductivity of Granular Soils from Particle Size Parameters

Wildfire Impacts on Slope Stability Triggering in Mountain Areas

Experimental Investigation on Hydraulic Properties of Granular Sandstone and Mudstone Mixtures

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