From aperture characterization to hydraulic properties of fractures

Tsakiroglou, Christos D.; Klint, Knud Erik S.; Nilsson, Bertel; Θεοδωροπούλου, Μαρία; Aggelopoulos, C.A.

doi:10.1016/j.geoderma.2012.02.027

Cited by 9 publications

(7 citation statements)

References 45 publications

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“…Cracks are always filled with sand grains or rock fragments, which had a significant role in providing high-amplitude reflections (Han et al, 2016;Dal et al, 2019) . Although the co-offset results only distinguished the envelope curves of different crack configurations, the soil cracks always had different widths and inclusions as well (Tsakiroglou et al, 2012;Yang et al, 2016), where the radar reflections provided by could not be distinguished.…”

Section: Effect Of Crack Properties On Preferential Flowmentioning

confidence: 87%

“…It has been shown that inclusions (Yang et al, 2016;She, 2020), width (Ou Yang, 2020), and configuration (Liu and She, 2020) influence the infiltration process. For simplicity, soil cracks are always assumed to resemble smooth parallel plates (Tsakiroglou et al, 2012;Rouchier et al, 2012). Therefore, three properties of different inclusions (sand grains and rock fragments), crack widths (1, 1.5, and 2 cm), and configurations (I-shape, V-shape, and Λ-shape) for infiltration were simulated (Figure 2d and Table 2).…”

Section: Infiltration Experiments Designmentioning

confidence: 99%

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Investigating the effect of soil cracks on preferential flow using ground-penetration radar surveys and infiltration experiment in karst, Southwest China

Hou

Cheng

Guan

2022

Preprint

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Soil cracks significantly affect preferential flow; however, there are some uncertainties associated with the effect of soil cracks on preferential flow in karst areas in southwest China. In this study, ground-penetrating radar (GPR) was applied to pedons to investigate the soil crack properties (inclusion, width, and configuration). Blue dye tracing experiments were designed, based on geophysical detection results, to assess the influences of inclusions (sand grains and rock fragments), crack width (1, 1.5, and 2 cm), and configuration (I-shape, V-shape, and Λ-shape) on the preferential flow. Our results indicated that (1) GPR envelope can describe the configuration of isolated soil cracks; (2) the Brilliant Blue FCF (C.I. Food Blue 2) infiltration rate and depth were over 1.5 times slower and 1.2–3.8 times lower those of water, respectively, during infiltration; (3) soil cracks can accelerate infiltration and increase the maximum dye-penetration depth, cumulative infiltration, and wetting front depth by at least an average of 5.2% and 63.2%, respectively; and (4) the I- and Λ-shaped soil crack configurations contributed to preferential flow, while the flow was not observed along the V-shaped configuration crack pore paths. The I-shaped configurations, with a width of 1.5 cm, were filled with rock fragments and had higher preferential flow ratios (18.2%–52.3%) and length indexes (4.0%–33.8%) than those of other configurations. Inclusions, crack widths, and configurations had significant influences on preferential flow ( p < 0.05). The influence of soil crack properties on preferential flow cannot be neglected during vegetation restoration and groundwater security processes in karst areas.

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Section: Effect Of Crack Properties On Preferential Flowmentioning

confidence: 87%

Section: Infiltration Experiments Designmentioning

confidence: 99%

Investigating the effect of soil cracks on preferential flow using ground-penetration radar surveys and infiltration experiment in karst, Southwest China

Hou

Cheng

Guan

2022

Preprint

View full text Add to dashboard Cite

show abstract

“…Cracks are always filled with inclusions, and these inclusions significantly contribute to high‐amplitude reflections (Dal Bo et al, 2019; Han et al, 2016). Although the co‐offset results distinguish only the envelope curves of different crack configurations, soil cracks always have different widths and inclusions (Tsakiroglou et al, 2012; Yang et al, 2016), and the radar reflections cannot distinguish these features.…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies have shown that the inclusions (Liu & She, 2020a, 2020b; Yang et al, 2016), widths (Ou Yang, 2020), and configurations (Liu & She, 2020a, 2020b) of cracks all influence the infiltration process. For simplicity, soil cracks are always assumed to resemble smooth, parallel plates (Rouchier et al, 2012; Tsakiroglou et al, 2012). Therefore, three properties of different crack inclusions (sand grains and rock fragments), crack widths (1, 1.5, and 2 cm), and crack configurations (I‐shape, V‐shape, and Λ‐shape) were simulated for infiltration (Figure 2d and Table 2).…”

Section: Methodsmentioning

confidence: 99%

Investigating the effect of soil cracks on preferential flow using a dye tracing infiltration experiment in karst in Southwest China

2022

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Soil cracks significantly affect the preferential flow, and various uncertainties are associated with the effect of soil cracks on preferential flow in karst areas in Southwest China. This study investigated soil crack properties (inclusions, width, and configuration) by applying ground‐penetrating RADAR (GPR) to pedons. Blue dye‐tracing experiments were designed based on the geophysical detection results to assess the influences of crack inclusions (sand grains and rock fragments), crack widths (1, 1.5, and 2 cm), and configurations (I‐shape, V‐shape, and Λ‐shape) on preferential flow. The following results were obtained: (1) the GPR envelope can describe the configuration of isolated soil cracks; (2) soil cracks can accelerate infiltration and increase the maximum dye‐penetration depth, cumulative infiltration, and wetting‐front depth by averages of at least 5.2%, 63.2% and 4.4%, respectively; and (3) the I‐ and Λ‐shaped soil crack configurations contributed to preferential flow, but the preferential flow was not observed along the V‐shaped‐configuration‐crack pore paths despite the retardation of brilliant blue FCF. The I‐shaped configurations, with a crack width of 1.5 cm, were filled with rock fragments and had higher preferential flow ratios (18.2%–52.3%) and length indices (4.0%–33.8%) compared to the other configurations. In summary, inclusions, crack width, and configuration significantly influence the preferential flow (p < 0.05), and the influence of these soil crack properties on preferential flow cannot be neglected during vegetation restoration and groundwater security operations in karst areas.

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“…The approximate elevation of hydraulic fractures is indicated by dashed colored lines (Tzovolou et al 2009;Tsakiroglou et al 2012) and preferential flow pathways of microporous matrix (Aggelopoulos and Tsakiroglou 2009). During the initial stages of ventilation, the air flow at high rate may displace trapped NAPL ganglia and transfer a small amount of NAPL from high to low NAPL saturation areas.…”

Section: Measurement Of Napl Removal Efficiency In Field Experimentsmentioning

confidence: 99%

In situ bioventing of the vadose zone of multi-scale heterogeneous soils

Tzovolou¹,

Θεοδωροπούλου²,

Blanchet³

et al. 2015

Environ Earth Sci

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International audienceA bioventing pilot test was performed on onecell of the vadose zone of a low permeability and fracturedsite polluted by jet fuel. Air was injected and extractedthrough hydraulic fractures that were installed to enhanceeffectively the horizontal permeability of the soil. Thebiodegradability of pollutants was evaluated with lab-scalestudies in batch reactors and soil columns, respectively. Toassess the process efficiency, soil samples were collectedfrom seven depths of twelve wells of the pilot Cell, thehydrocarbons were extracted with dichloromethane, andanalyzed with gas chromatography/mass spectroscopy andgas chromatography/flame ionization detection. Data obtainedfrom the complete characterization of the porestructure of the soil were employed to understand the mainmechanisms of pollutant removal. Due to the heterogeneousnature of the porous matrix over a broad range ofpore sizes (from 1 nm to 1 mm), the rate of intrinsicbiodegradation of jet fuel in matrix was limited. The mainpollutant removal mechanism was the ventilation in whichmost volatile hydrocarbons vaporized and diffused towardthe gas phase that was flowing along the preferential flowpathways. Hydraulic fractures facilitated and acceleratedthe pollutant remediation rate by enhancing the interconnectivityof the porous matrix with natural fracture systemsor any other type of natural preferential flow pathway

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From aperture characterization to hydraulic properties of fractures

Cited by 9 publications

References 45 publications

Investigating the effect of soil cracks on preferential flow using ground-penetration radar surveys and infiltration experiment in karst, Southwest China

Investigating the effect of soil cracks on preferential flow using ground-penetration radar surveys and infiltration experiment in karst, Southwest China

Investigating the effect of soil cracks on preferential flow using a dye tracing infiltration experiment in karst in Southwest China

In situ bioventing of the vadose zone of multi-scale heterogeneous soils

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