Osmotic flow through a Cretaceous clay in southern Saskatchewan, Canada

2001 ◽  
Vol 38 (5) ◽  
pp. 1025-1033 ◽  
Author(s):  
Bradley D Cey ◽  
S L Barbour ◽  
M Jim Hendry
Keyword(s):  
Hydraulic Conductivity ◽  
Pore Fluid ◽  
Experimental Program ◽  
Diffuse Double Layer ◽  
Semipermeable Membranes ◽  
Osmotic Flow ◽  
Fluid Concentration ◽  
Osmotic Behaviour ◽  
Flow Through ◽  
Constant Head

Clays and shales can act as semipermeable membranes, causing osmotic flow and (or) osmotically induced fluid pressures. Despite laboratory proof of the osmotic behaviour of clay-rich geologic material, the influence of this osmotic behaviour on in situ groundwater flow and solute transport is inconclusive. This is due in part to the lack of laboratory experimental work involving undisturbed core samples, and to the lack of field-scale research. The ability of undisturbed clay samples to conduct flow hydraulically and osmotically was investigated using dilute salt solutions. Undisturbed Cretaceous clay samples from southern Saskatchewan were used in a laboratory experimental program. The experiments included constant-head hydraulic conductivity (Kh) tests and osmotic flow tests conducted over a range of pore-fluid concentrations of 0.054–1.12 equiv./L. The clay samples exhibited semipermeable membrane behaviour by conducting flow osmotically. The hydraulic conductivity of the clay increased by a factor of two as the pore-fluid concentration increased from 0.070 to 0.56 equiv./L. Osmotic efficiencies ranged from 0.0028 to 0.42 for concentrations from 0.84 to 0.096 equiv./L. Both the osmotic compressibility and osmotic efficiency decreased with increasing pore-fluid concentration. The behaviour of the clay was consistent with diffuse double-layer theory.Key words: osmotic flow, Cretaceous clay, salt, hydraulic conductivity.

scholarly journals An Empirical Model for Estimation of Permeability of Porous Media based on its Gradation Parameters

2020 ◽  
Vol 8 (5) ◽  
pp. 669-673
Keyword(s):  
Porous Media ◽  
Hydraulic Conductivity ◽  
Empirical Model ◽  
Low Head ◽  
Flow Through ◽  
Constant Head

In the present study the hydraulic conductivity of the porous media has been related to its gradation parameters. Nine cohesion-less soils of different gradations were tested in a constant head permeameter. A low head of water, standardised to viscosity at 20°C, was used to avoid the turbulence. It was observed that the hydraulic conductivity varied significantly with respect to the gradation parameters. The empirical model developed on the basis of this study can be helpful for more rational estimation of the flow through non-cohesive porous media on the basis of its gradation characteristics.

Joint estimation of hydraulic conductivities of two sand samples in a W-tube system with a bi-exponential response

2015 ◽  
Vol 47 (2) ◽  
pp. 344-355 ◽  
Author(s):  
Mariusz Kaczmarek ◽  
Filip Wolny ◽  
Marek Marciniak
Keyword(s):  
Hydraulic Conductivity ◽  
Water Flow ◽  
Optimization Procedure ◽  
Joint Estimation ◽  
Exponential Rate ◽  
Tube System ◽  
Two Samples ◽  
Independent Constant ◽  
Flow Through ◽  
Constant Head

The motivation for this paper is the practical problem of interpreting bi-exponential rate-of-rise curves that are observed during many field piezometric tests. In the authors' previous study, a laboratory W-tube system of water flow through two samples of sand was introduced with an adequate mathematical model. The desired bi-exponential character of water flow was obtained by placing two different samples of sand in separate but connected columns. In the present paper, a so-called inverse problem is solved. The optimization procedure is applied in order to jointly estimate a pair of hydraulic conductivity values based on experimentally recorded bi-exponential rate-of-rise curves. The obtained values of hydraulic conductivities are presented and compared to the values determined from independent constant-head permeability tests conducted for the analyzed sands. The results of this identification procedure varied in accuracy. The mean percent errors between the hydraulic conductivity values measured jointly and independently for the analyzed experimental series were in the range of 8.8 to 37.2%. The discussion presents the restrictions of this interpretational method and suggests further modeling plans.

Evaluation of the impact of pore fluid chemistry on the hydromechanical behaviour of clay-based sealing materials

2011 ◽  
Vol 48 (2) ◽  
pp. 199-213 ◽  
Author(s):  
Sumi Siddiqua ◽  
James Blatz ◽  
Greg Siemens
Keyword(s):  
Hydraulic Conductivity ◽  
Pore Fluid ◽  
Experimental Program ◽  
Dry Density ◽  
Analysis And Design ◽  
Barrier Materials ◽  
Fluid Chemistry ◽  
Pore Fluid Chemistry ◽  
Swell Potential ◽  
The Impact

The results of an experimental program undertaken to evaluate the impact of pore fluid salinity on the hydromechanical performance of light and dense backfill materials are presented. Light and dense backfills are engineered barrier materials that are being examined in the Canadian concept for storage of spent fuel in a deep geological repository. The current research investigates the impact of pore fluid chemistry on the swelling, compressibility, stiffness, and hydraulic conductivity parameters of light and dense backfills that are required as material parameters for analysis and design. In these tests, pore fluid chemistry was selected to represent groundwater within potential host units including granite and limestone rock. Results show that the performance of light backfill is significantly affected by changes in pore fluid chemistry. The swell potential of light backfill decreases with increasing salinity of the solution. The hydraulic conductivity decreases with increasing effective montmorillonite dry density and specimens saturated with saline solution have higher hydraulic conductivity than those saturated with distilled water. Conversely, the behaviour of dense backfill is governed mainly by the crushed granite component and therefore changes to the pore fluid chemistry have relatively little effect. Results of dense backfill tests confirm the material performance as a sealing material.

A review of the influence of clay–brine interactions on the geotechnical properties of Ca-montmorillonitic clayey soils from western Canada

1993 ◽  
Vol 30 (6) ◽  
pp. 920-934 ◽  
Author(s):  
S.L. Barbour ◽  
N. Yang
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Hydraulic Conductivity ◽  
Geotechnical Properties ◽  
Pore Fluid ◽  
Western Canada ◽  
Diffuse Double Layer ◽  
Clayey Soils ◽  
Fluid Chemistry ◽  
Pore Fluid Chemistry

Natural Ca-montmorillonite clay soils or engineered clay barriers in western Canada are often used to contain brine generated from the surface disposal of potash tailings or from drilling activities associated with the oil and gas industry. The performance of these barriers has ranged from excellent to poor. The influence of salt brines on the geotechnical properties of these soils has been recognized as a potentially important factor for some time. It has been well documented in the literature that the behavior of clayey soils is strongly influenced by physicochemical interactions between clay particles and pore-fluid chemistry; consequently, the properties of these soils are sensitive to changes in the electrolyte concentration of the pore fluid. An increase in the concentration of the pore fluid to the levels of a concentrated brine can cause significant changes in the geotechnical properties of the soil. In this paper, the impact of brine contamination on the geotechnical properties of two Ca-montmorillonitic clayey soils of glacial origin from western Canada is reviewed. The influence of clay–brine interactions on the index properties (liquid limit, plastic limit, plastic index, mineralogy, density, grain size, and compaction characteristics), mechanical properties (volume change and shear strength), and hydraulic properties (hydraulic conductivity) is described. A quantitative explanation for the changes that occur in the hydraulic and mechanical properties of these soils as a result of brine permeation is also provided. This explanation relates the changes in pore-fluid chemistry to changes in an effective physicochemical stress state. This approach may be used to predict the changes in hydraulic conductivity, volume, or shear strength of a clayey soil as a result of brine contamination. Key words : clay–brine interactions, diffuse double layer, hydraulic conductivity, soil structure, physicochemical.

The effects of organic fluids on physicochemical parameters of fine-grained soils

2000 ◽  
Vol 37 (5) ◽  
pp. 943-950 ◽  
Author(s):  
Abidin Kaya ◽  
Hsai-Yang Fang
Keyword(s):  
Dielectric Constant ◽  
Hydraulic Conductivity ◽  
Zeta Potential ◽  
Physicochemical Properties ◽  
Physicochemical Parameters ◽  
Soil Structure ◽  
Pore Fluid ◽  
Diffuse Double Layer ◽  
Fine Grained ◽  
Repulsive Forces

Researchers have shown that properties of fine-grained soils such as hydraulic conductivity change significantly when the pore fluid is replaced with organic liquids. In general, such changes have been reported as a function of the dielectric constant of the pore fluid and attributed to changes in soil structure. However, mechanisms causing changes in soil structure are yet to be understood. In this paper, the physicochemical properties of kaolinite, bentonite, and a local soil are determined as a function of the dielectric constant of pore fluids to evaluate the mechanisms causing changes in soil structure and, in turn, hydraulic conductivity. The physicochemical parameters determined in this study are cation exchange capacity (CEC), zeta potential (ζ), surface charge density, pore-size distribution, and Atterberg limits. Results show that physicochemical properties change as the dielectric constant of the pore fluid changes, such that as the dielectric constant of the pore fluid approaches that of the soil, the repulsive and attractive forces diminish; yet, there is a net increase in the attractive forces, causing aggregation of the particles. Based on the results of this study, it is suggested that as repulsive forces decrease the soil particles tend to flocculate and form aggregates due to attractive forces among particles, leading to a net increase in the effective flow area, resulting in increased hydraulic conductivity of the soil - pore fluid system.Key words: fine-grained soils, diffuse double layer, attractive forces, physicochemical parameters, CEC, zeta potential.

scholarly journals Hydraulic Conductivity of Polymer-Amended Sand-Bentonite Backfills Permeated with Lead Nitrate Solutions

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Sheng-Qiang Shen ◽  
Ming-Li Wei
Keyword(s):  
Hydraulic Conductivity ◽  
Water Content ◽  
Applied Pressure ◽  
Lead Nitrate ◽  
Bound Water ◽  
Liquid Limit ◽  
Filter Press ◽  
Diffuse Double Layer ◽  
Comparison Results ◽  
Pb Concentration

Hydraulic conductivity of sand-bentonite (SB) backfills amended with polyanionic cellulose (PAC) to lead nitrate (Pb(NO3)2) solutions was evaluated experimentally in this study. PAC-amended sand-bentonite (PSB) backfills were synthesized by mixing sand-bentonite mixture with 0.3 to 1.2% dry PAC (by total dry mixture mass) and mixed with a certain weight of conventional bentonite (CB) slurry. The rheology properties including the filtrate loss, viscosity, density, and pH testes of slurry with various bentonite dosages were measured to determine the reasonable CB dosage of slurry. The slump tests on PSB backfills with various mass slurries were conducted to determine the corresponding water content of backfills with slump 125 ± 5 mm. Under the applied pressure 100 kPa, the hydraulic conductivity to Pb(NO3)2 solutions (kc) of PSB backfills with various PAC contents was evaluated based on the modified filter press (MFP) tests, to ascertain the optimum PAC content of PSB backfills when permeated with Pb(NO3)2 solutions. Index properties, including the specific gravity (Gs) and liquid limit (wL) of PSB backfills, were measured after MFP tests. The MFP tests for PSB backfills were then conducted under various applied pressures to obtain the relationship between void ratio (e) and hydraulic conductivity of backfills. Finally, the flexible-wall permeability test (FWP test) under osmotic pressure 100 kPa was conducted to verify the effectiveness of the MFP test. The results indicate that slurry with 8% bentonite dosage is the reasonable choice in slurry wall construction. PSB has lower GS and higher wL compared to SB; increasing Pb concentration leads to GS of PSB increased and wL of PSB decreased. PSB with 0.6% PAC content is supposed as the optimum proportion of backfills when permeated with concentrated Pb(NO3)2 solution. PAC adsorbs large amount of bound water, which leads to higher water content (w) and e of PSB backfills, while lead ions (Pb) cause the diffuse double layer (DDL) of bentonite compressed and e of PSB backfills reduced. The kc of PSB-0.6 remains lower than 10−9 m/s and increases less than 10 times though the Pb concentration was up to 500 mM, demonstrating that the hydraulic performance of backfills can be improved effectively in Pb(NO3)2 solution by the additive PAC. The comparison results between k from MFP tests and FWP tests show that the MFP test is an effective and easy evaluation of hydraulic conductivity of backfills.

scholarly journals Comparison of three measurement methods of saturated hydraulic condutivity

2006 ◽  
Vol 3 (3) ◽  
pp. 987-1019 ◽  
Author(s):  
C. Fallico ◽  
E. Migliari ◽  
S. Troisi
Keyword(s):  
Hydraulic Conductivity ◽  
Measurement Method ◽  
Sandy Loam ◽  
Measurement Methods ◽  
Soil Core ◽  
Statistical Parameters ◽  
Factors Affecting ◽  
Average Value ◽  
Constant Head ◽  
Log Normal

Abstract. After pointing out the importance of the saturated hydraulic conductivity (ks) measurements and the difficulties and uncertainties that are present, and after recalling salient aspects of three well-known measurement methods of this parameter (i.e. constant-head tension infiltrometer (TI) method, constant-head pressure infiltrometer (PI) method and soil core (SC) estimates method), the results of an investigation on data which were obtained during a measurement campaign on an area of 800 m2, on a sandy loam hillslope, located in Southern Italy, were carried out again here. Three sets of values of ks, obtained with these measurement methods, were analyzed statistically, verifying that the log-normal distribution describes these better than the normal one; moreover, the more significant statistical parameters of each set were compared (average value , amplitude A, coefficient of variation CV and standard deviation SD), individualizing the more significant differences. The greatest value of hydraulic conductivity was found with method (PI), while the smallest with (SC) and the intermediate with (TI); these differences were translated into macroporosity and into the influence of the single measurement method. Moreover, referring to the possible factors affecting the results, the importance can be noted of the structure, the texture and the soil events, in terms of utilization, which can affect the measure of ks leading often to very different values even for similar soils, but with a different history, independently of the coincidence of the measurement points and they can be determining to explain the differences affecting the results obtained in analogous investigations by other researchers. Having confirmed that generalization is not possible, the need was emphasized to adopt the necessary devices relating to the specific measurement method, case by case, and to carefully explain the obtained results, in the light of the peculiarities and the limits of each situation. Finally, the results of similar statistical analysis carried out on a greater number of ks values, measured through the (TI) and (PI) methods are shown in this paper, with some statistical considerations on the increasing of the measurements number.

scholarly journals CONTROLE ESTATÍSTICO DE QUALIDADE DA CONDUTIVIDADE HIDRÁULICA EM LUVISSOLO E NEOSSOLO COM VARIAÇÃO DA DENSIDADE DO SOLO

Irriga ◽  
2019 ◽  
Vol 24 (1) ◽  
pp. 16-24
Author(s):  
Floriano Luiz Suszek ◽  
Silvio Cesar Sampaio ◽  
Vera Lucia Antunes De Lima
Keyword(s):  
Hydraulic Conductivity ◽  
Control Charts ◽  
Density Variation ◽  
Statistical Quality Control ◽  
Agricultural Drainage ◽  
Sensitivity Index ◽  
Statistical Control ◽  
Soil Physics ◽  
Constant Head ◽  
Improving Accuracy

CONTROLE ESTATÍSTICO DE QUALIDADE DA CONDUTIVIDADE HIDRÁULICA EM LUVISSOLO E NEOSSOLO COM VARIAÇÃO DA DENSIDADE DO SOLO     FLORIANO LUIZ SUSZEK1; SILVIO CÉSAR SAMPAIO2 E VERA LÚCIA ANTUNES DE LIMA3   1Doutor em Engenharia Agrícola, Programa de Pós-Graduação em Engenharia Agrícola (PGEAGRI), Universidade Estadual do Oeste do Paraná (UNIOESTE), Rua Universitária, nº 1619 – Jd. Universitário, CEP: 85809-110, Cascavel, Paraná, Brasil, [email protected]. 2Universidade Estadual do Oeste do Paraná, Departamento de Recursos Hídricos e Saneamento Ambiental, Rua Universitária, nº 1619 – Jd. Universitário, CEP: 85809-110, Cascavel, Paraná, Brasil, [email protected]. 3Universidade Federal de Campina Grande (UFCG), Centro de Tecnologia e Recursos Naturais, Rua Aprígio Veloso, nº 882, Universitário, CEP: 58429-900, Campina Grande, Paraíba, Brasil, [email protected].     1 RESUMO   A condutividade hidráulica é um dos principais fatores para dimensionamento de sistemas de drenagem agrícola. Uma das metodologias utilizadas para a obtenção da condutividade hidráulica é o permeâmetro de carga constante. Porém a grande variação dos resultados gera necessidade de análises para melhorar a precisão destes, como o uso de gráficos de controle estatístico de qualidade. Este trabalho analisou por meio de gráficos de controle, a metodologia do permeâmetro de carga constante para dois solos diferentes na obtenção da condutividade hidráulica, variando a densidade dos solos e analisando seu índice de sensibilidade. O LUVISSOLO CRÔMICO é mais sensível à variação de densidade do solo, para a condutividade hidráulica, do que o NEOSSOLO REGOLÍTICO. Os gráficos de controle foram úteis na melhoria da precisão dos valores analisados, mostrando a variação da condutividade hidráulica e quais foram os pontos fora dos limites desejáveis.   Palavras-chave: Drenagem agrícola, propriedades físicas do solo, permeâmetro de carga constante.     SUSZEK, F. L.; SAMPAIO, S. C.; LIMA, V. L. A. de STATISTICAL QUALITY CONTROL IN HYDRAULIC CONDUCTIVITY FOR LUVISOL AND ENTISOL WITH DENSITY VARIATION     2 ABSTRACT   Hydraulic conductivity is one of the main factors for the design of agricultural drainage systems. One of the methodologies used to obtain the hydraulic conductivity is the constant head permeameter. However, the large variation of results generates the need for analyzes to improve their accuracy, such as the use of quality statistical control graphs. This work analyzed, by means of control charts, the methodology of constant head permeameter for two different soils in obtaining hydraulic conductivity, varying the density of soils and analyzing their sensitivity index. Luvisol is more sensitive to density variation, for hydraulic conductivity, than  entisol. Control graphs were useful in improving  accuracy of the analyzed values, showing the variation of hydraulic conductivity and what were the points outside the desirable limits.   Keywords: Agricultural drainage, soil physics properties, constant head permeameter.

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