Quantification of the hydraulic diffusivity of a bentonite‐sand mixture using the water head decrease measured upon sudden flow interruption
This paper presents a new modelling approach to quantify the hydraulic diffusivity of low‐permeability unconsolidated porous media under confined saturated‐flow conditions in the laboratory. The derived analytical solution for the transient variation of the hydraulic head after flow interruption was...
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| Veröffentlicht in: | Hydrological processes 2020-04, Vol.34 (8), p.1934-1948 |
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| creator | Schäfer, Gerhard Berez, Amor |
| description | This paper presents a new modelling approach to quantify the hydraulic diffusivity of low‐permeability unconsolidated porous media under confined saturated‐flow conditions in the laboratory. The derived analytical solution for the transient variation of the hydraulic head after flow interruption was applied to experimental data obtained from continuous measurements of the water pressure at two locations in the soil column. Three soil samples made of a mixture of natural bentonite (at different mass fractions) and medium sand were studied during a series of stepwise constant flow rates of water. The numerical results well fit the experimentally measured decrease of the dimensionless hydraulic head. The study shows that the increase of the mass fraction of bentonite in the soil sample from 10 to 30% is accompanied by a strong decrease of the hydraulic diffusivity from 2.4 × 10−2 to 1.1 × 10−3 m2 s−1, which is clearly due to the decrease of the hydraulic conductivity of the soil sample. The specific storages obtained for each of the three samples are in the same order of magnitude and seem to decrease with the increase of mass fraction of bentonite. However, they clearly reflect the predominant portion of the compressibility of the porous medium compared with that of water. Compared with reported literature values for clayey soils, the specific storage values in this study are slightly higher, varying within the range of 2 × 10−3 to 8.1 × 10−3 m−1.. The experimental results also give insight into the limitations of the modelling approach. In the case of low‐permeability soils (K |
| doi_str_mv | 10.1002/hyp.13704 |
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To quantify the hydraulic diffusivity of a bentonite‐sand mixture, an analytical solution derived for the transient variation of the hydraulic head after sudden flow interruption was applied to experimental data containing continuous measurements of water pressure at two locations in the laboratory column. Using the hydraulic conductivity of the soil sample measured at the steady‐state flow rate preceding the flow interruption, further soil properties such as the specific storage and the coefficient of volume compressibility were then obtained.</description><identifier>ISSN: 0885-6087</identifier><identifier>EISSN: 1099-1085</identifier><identifier>DOI: 10.1002/hyp.13704</identifier><language>eng</language><publisher>Hoboken, USA: John Wiley & Sons, Inc</publisher><subject>analytical solution ; Bentonite ; bentonite‐sand mixture ; Clay ; Clay soils ; coefficient of volume compressibility ; column experiment ; Compressibility ; Computational fluid dynamics ; Continental interfaces, environment ; Diffusion coefficients ; Diffusivity ; Dimensionless numbers ; Exact solutions ; Flow rates ; Flow velocity ; Fluid flow ; Head (fluid mechanics) ; Hydraulic conductivity ; hydraulic diffusivity ; Hydraulics ; Hydrostatic pressure ; Mass ; Modelling ; Permeability ; Piezometric head ; Porous media ; Sand ; Sciences of the Universe ; Soil ; Soil columns ; Soil compressibility ; Soil permeability ; Soils ; specific storage ; Storage ; Water pressure</subject><ispartof>Hydrological processes, 2020-04, Vol.34 (8), p.1934-1948</ispartof><rights>2020 John Wiley & Sons Ltd</rights><rights>2020 John Wiley & Sons, Ltd.</rights><rights>Distributed under a Creative Commons Attribution 4.0 International License</rights><lds50>peer_reviewed</lds50><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-a3544-12ece6285ae68d5520d70cfa11154e10e2fcd7e49f65574d8ef2586f9d8afc083</citedby><cites>FETCH-LOGICAL-a3544-12ece6285ae68d5520d70cfa11154e10e2fcd7e49f65574d8ef2586f9d8afc083</cites><orcidid>0000-0002-7800-4429</orcidid></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktopdf>$$Uhttps://onlinelibrary.wiley.com/doi/pdf/10.1002%2Fhyp.13704$$EPDF$$P50$$Gwiley$$H</linktopdf><linktohtml>$$Uhttps://onlinelibrary.wiley.com/doi/full/10.1002%2Fhyp.13704$$EHTML$$P50$$Gwiley$$H</linktohtml><link.rule.ids>230,314,780,784,885,1417,27924,27925,45574,45575</link.rule.ids><backlink>$$Uhttps://hal.science/hal-02979090$$DView record in HAL$$Hfree_for_read</backlink></links><search><creatorcontrib>Schäfer, Gerhard</creatorcontrib><creatorcontrib>Berez, Amor</creatorcontrib><title>Quantification of the hydraulic diffusivity of a bentonite‐sand mixture using the water head decrease measured upon sudden flow interruption</title><title>Hydrological processes</title><description>This paper presents a new modelling approach to quantify the hydraulic diffusivity of low‐permeability unconsolidated porous media under confined saturated‐flow conditions in the laboratory. The derived analytical solution for the transient variation of the hydraulic head after flow interruption was applied to experimental data obtained from continuous measurements of the water pressure at two locations in the soil column. Three soil samples made of a mixture of natural bentonite (at different mass fractions) and medium sand were studied during a series of stepwise constant flow rates of water. The numerical results well fit the experimentally measured decrease of the dimensionless hydraulic head. The study shows that the increase of the mass fraction of bentonite in the soil sample from 10 to 30% is accompanied by a strong decrease of the hydraulic diffusivity from 2.4 × 10−2 to 1.1 × 10−3 m2 s−1, which is clearly due to the decrease of the hydraulic conductivity of the soil sample. The specific storages obtained for each of the three samples are in the same order of magnitude and seem to decrease with the increase of mass fraction of bentonite. However, they clearly reflect the predominant portion of the compressibility of the porous medium compared with that of water. Compared with reported literature values for clayey soils, the specific storage values in this study are slightly higher, varying within the range of 2 × 10−3 to 8.1 × 10−3 m−1.. The experimental results also give insight into the limitations of the modelling approach. In the case of low‐permeability soils (K < 2 × 10−6 ms−1) and steady‐flow conditions with low Reynolds numbers, for example, Re < 0.003, it is recommended to choose a time duration for flow interruption between subsequent flow rate steps of longer than 5 s. For high‐permeability porous media, to increase the precision of the quantified hydraulic diffusivity, it might be useful to select a measuring frequency significantly higher than 1 Hz.
To quantify the hydraulic diffusivity of a bentonite‐sand mixture, an analytical solution derived for the transient variation of the hydraulic head after sudden flow interruption was applied to experimental data containing continuous measurements of water pressure at two locations in the laboratory column. Using the hydraulic conductivity of the soil sample measured at the steady‐state flow rate preceding the flow interruption, further soil properties such as the specific storage and the coefficient of volume compressibility were then obtained.</description><subject>analytical solution</subject><subject>Bentonite</subject><subject>bentonite‐sand mixture</subject><subject>Clay</subject><subject>Clay soils</subject><subject>coefficient of volume compressibility</subject><subject>column experiment</subject><subject>Compressibility</subject><subject>Computational fluid dynamics</subject><subject>Continental interfaces, environment</subject><subject>Diffusion coefficients</subject><subject>Diffusivity</subject><subject>Dimensionless numbers</subject><subject>Exact solutions</subject><subject>Flow rates</subject><subject>Flow velocity</subject><subject>Fluid flow</subject><subject>Head (fluid mechanics)</subject><subject>Hydraulic conductivity</subject><subject>hydraulic diffusivity</subject><subject>Hydraulics</subject><subject>Hydrostatic pressure</subject><subject>Mass</subject><subject>Modelling</subject><subject>Permeability</subject><subject>Piezometric head</subject><subject>Porous media</subject><subject>Sand</subject><subject>Sciences of the Universe</subject><subject>Soil</subject><subject>Soil columns</subject><subject>Soil compressibility</subject><subject>Soil permeability</subject><subject>Soils</subject><subject>specific storage</subject><subject>Storage</subject><subject>Water pressure</subject><issn>0885-6087</issn><issn>1099-1085</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2020</creationdate><recordtype>article</recordtype><recordid>eNp1kc9u1DAQxi0EEkvhwBtY4sQh7dgbJ86xqoBFWqkg0UNPlonHxFXWCf7TbW48QcUz8iT1dhGcepmRZn7zfSN9hLxlcMoA-NmwzKds3UL9jKwYdF3FQIrnZAVSiqoB2b4kr2K8AYAaJKzI_desfXLW9Tq5ydPJ0jQgHRYTdB5dT42zNkd369JyWGr6HX2avEv459fvqL2hO3eXckBaKP_j8XqvEwY6oDbUYB9QR6S7UgtlaJ6LTczGoKd2nPbU-UKHPB_8X5MXVo8R3_ztJ-Tq44dvF5tqe_np88X5ttJrUdcV49hjw6XQ2EgjBAfTQm81Y0zUyAC57U2LdWcbIdraSLRcyMZ2Rmrbg1yfkPdH3UGPag5up8OiJu3U5nyrDjPgXdtBB7essO-O7BymnxljUjdTDr68p_hadoLxhsF_xT5MMQa0_2QZqEM0qkSjHqMp7NmR3bsRl6dBtbn-crx4AKCmk7k</recordid><startdate>20200415</startdate><enddate>20200415</enddate><creator>Schäfer, Gerhard</creator><creator>Berez, Amor</creator><general>John Wiley & Sons, Inc</general><general>Wiley Subscription Services, Inc</general><general>Wiley</general><scope>AAYXX</scope><scope>CITATION</scope><scope>7QH</scope><scope>7ST</scope><scope>7TG</scope><scope>7UA</scope><scope>8FD</scope><scope>C1K</scope><scope>F1W</scope><scope>FR3</scope><scope>H96</scope><scope>KL.</scope><scope>KR7</scope><scope>L.G</scope><scope>SOI</scope><scope>1XC</scope><orcidid>https://orcid.org/0000-0002-7800-4429</orcidid></search><sort><creationdate>20200415</creationdate><title>Quantification of the hydraulic diffusivity of a bentonite‐sand mixture using the water head decrease measured upon sudden flow interruption</title><author>Schäfer, Gerhard ; Berez, Amor</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-a3544-12ece6285ae68d5520d70cfa11154e10e2fcd7e49f65574d8ef2586f9d8afc083</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2020</creationdate><topic>analytical solution</topic><topic>Bentonite</topic><topic>bentonite‐sand mixture</topic><topic>Clay</topic><topic>Clay soils</topic><topic>coefficient of volume compressibility</topic><topic>column experiment</topic><topic>Compressibility</topic><topic>Computational fluid dynamics</topic><topic>Continental interfaces, environment</topic><topic>Diffusion coefficients</topic><topic>Diffusivity</topic><topic>Dimensionless numbers</topic><topic>Exact solutions</topic><topic>Flow rates</topic><topic>Flow velocity</topic><topic>Fluid flow</topic><topic>Head (fluid mechanics)</topic><topic>Hydraulic conductivity</topic><topic>hydraulic diffusivity</topic><topic>Hydraulics</topic><topic>Hydrostatic pressure</topic><topic>Mass</topic><topic>Modelling</topic><topic>Permeability</topic><topic>Piezometric head</topic><topic>Porous media</topic><topic>Sand</topic><topic>Sciences of the Universe</topic><topic>Soil</topic><topic>Soil columns</topic><topic>Soil compressibility</topic><topic>Soil permeability</topic><topic>Soils</topic><topic>specific storage</topic><topic>Storage</topic><topic>Water pressure</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Schäfer, Gerhard</creatorcontrib><creatorcontrib>Berez, Amor</creatorcontrib><collection>CrossRef</collection><collection>Aqualine</collection><collection>Environment Abstracts</collection><collection>Meteorological & Geoastrophysical Abstracts</collection><collection>Water Resources Abstracts</collection><collection>Technology Research Database</collection><collection>Environmental Sciences and Pollution Management</collection><collection>ASFA: Aquatic Sciences and Fisheries Abstracts</collection><collection>Engineering Research Database</collection><collection>Aquatic Science & Fisheries Abstracts (ASFA) 2: Ocean Technology, Policy & Non-Living Resources</collection><collection>Meteorological & Geoastrophysical Abstracts - Academic</collection><collection>Civil Engineering Abstracts</collection><collection>Aquatic Science & Fisheries Abstracts (ASFA) Professional</collection><collection>Environment Abstracts</collection><collection>Hyper Article en Ligne (HAL)</collection><jtitle>Hydrological processes</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Schäfer, Gerhard</au><au>Berez, Amor</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Quantification of the hydraulic diffusivity of a bentonite‐sand mixture using the water head decrease measured upon sudden flow interruption</atitle><jtitle>Hydrological processes</jtitle><date>2020-04-15</date><risdate>2020</risdate><volume>34</volume><issue>8</issue><spage>1934</spage><epage>1948</epage><pages>1934-1948</pages><issn>0885-6087</issn><eissn>1099-1085</eissn><abstract>This paper presents a new modelling approach to quantify the hydraulic diffusivity of low‐permeability unconsolidated porous media under confined saturated‐flow conditions in the laboratory. The derived analytical solution for the transient variation of the hydraulic head after flow interruption was applied to experimental data obtained from continuous measurements of the water pressure at two locations in the soil column. Three soil samples made of a mixture of natural bentonite (at different mass fractions) and medium sand were studied during a series of stepwise constant flow rates of water. The numerical results well fit the experimentally measured decrease of the dimensionless hydraulic head. The study shows that the increase of the mass fraction of bentonite in the soil sample from 10 to 30% is accompanied by a strong decrease of the hydraulic diffusivity from 2.4 × 10−2 to 1.1 × 10−3 m2 s−1, which is clearly due to the decrease of the hydraulic conductivity of the soil sample. The specific storages obtained for each of the three samples are in the same order of magnitude and seem to decrease with the increase of mass fraction of bentonite. However, they clearly reflect the predominant portion of the compressibility of the porous medium compared with that of water. Compared with reported literature values for clayey soils, the specific storage values in this study are slightly higher, varying within the range of 2 × 10−3 to 8.1 × 10−3 m−1.. The experimental results also give insight into the limitations of the modelling approach. In the case of low‐permeability soils (K < 2 × 10−6 ms−1) and steady‐flow conditions with low Reynolds numbers, for example, Re < 0.003, it is recommended to choose a time duration for flow interruption between subsequent flow rate steps of longer than 5 s. For high‐permeability porous media, to increase the precision of the quantified hydraulic diffusivity, it might be useful to select a measuring frequency significantly higher than 1 Hz.
To quantify the hydraulic diffusivity of a bentonite‐sand mixture, an analytical solution derived for the transient variation of the hydraulic head after sudden flow interruption was applied to experimental data containing continuous measurements of water pressure at two locations in the laboratory column. Using the hydraulic conductivity of the soil sample measured at the steady‐state flow rate preceding the flow interruption, further soil properties such as the specific storage and the coefficient of volume compressibility were then obtained.</abstract><cop>Hoboken, USA</cop><pub>John Wiley & Sons, Inc</pub><doi>10.1002/hyp.13704</doi><tpages>15</tpages><orcidid>https://orcid.org/0000-0002-7800-4429</orcidid></addata></record> |
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| subjects | analytical solution Bentonite bentonite‐sand mixture Clay Clay soils coefficient of volume compressibility column experiment Compressibility Computational fluid dynamics Continental interfaces, environment Diffusion coefficients Diffusivity Dimensionless numbers Exact solutions Flow rates Flow velocity Fluid flow Head (fluid mechanics) Hydraulic conductivity hydraulic diffusivity Hydraulics Hydrostatic pressure Mass Modelling Permeability Piezometric head Porous media Sand Sciences of the Universe Soil Soil columns Soil compressibility Soil permeability Soils specific storage Storage Water pressure |
| title | Quantification of the hydraulic diffusivity of a bentonite‐sand mixture using the water head decrease measured upon sudden flow interruption |
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