scholarly journals Effect of Pore-Water Salinity on the Electrical Resistivity of Partially Saturated Compacted Clay Liners

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Yi Lu ◽  
Hossam Abuel-Naga ◽  
Qais Al Rashid ◽  
Md Farhad Hasan
Keyword(s):  
Electrical Resistivity ◽  
Moisture Content ◽  
Pore Water ◽  
Water Salinity ◽  
Dry Density ◽  
Constant Density ◽  
Compacted Clay ◽  
Clay Liners ◽  
Pore Water Salinity ◽  
Surface Conduction

The aim of this paper is to investigate the effect of pore-water salinity on the electrical resistivity (ER) of different compacted clay liners (CCLs) in terms of its mineralogical composition. For this purpose, an experimental programme was conducted where ERs of different kaolin-dominant CCL specimens, reconstituted using water having different concentrations of NaCl (0 M, 0.5 M, and 1.0 M), were measured. The kaolin-dominant CCL specimens tested in this study include pure kaolin, three different kaolin-bentonite mixtures, and three different kaolin-sand mixtures. The experimental results show that the ERs of CCL specimens decrease as the salt concentrations in pore water, moisture content, and dry density increase. At constant density and moisture content, the test results also indicate that increasing the sand content in kaolin-dominant CCL specimens increases its ER regardless of the water salinity level. This behaviour could be attributed to the lower surface conduction of sand compared to kaolin. However, at constant density and moisture content, increasing the bentonite content in kaolin-dominant CCL specimens decreases its ER in the distilled water environment as surface conduction of bentonite is higher compared to that of kaolin. On the contrary, in saltwater environments, ER increases as the bentonite content increases. This behaviour could be explained in terms of the expected aggregated microstructure of bentonite in the saltwater environment that could reduce the number and area of interparticle contacts, and consequently, increase the ER of CCL specimens.

Effect of evaporative drying on complex conductivity spectra of sandstones

Geophysics ◽  
2019 ◽  
Vol 84 (1) ◽  
pp. MR61-MR72 ◽  
Author(s):  
Zeyu Zhang ◽  
Andreas Weller ◽  
Sabine Kruschwitz ◽  
Sven Nordsiek
Keyword(s):  
Moisture Content ◽  
Pore Water ◽  
Imaginary Part ◽  
Power Law ◽  
Water Salinity ◽  
Complex Conductivity ◽  
The Real ◽  
Pore Water Salinity ◽  
The Impact ◽  
Conductivity Spectra

Dehydration is a common process occurring in natural environments, rocks, and building materials. Suitable methods for monitoring the changing moisture content should be identified. We have investigated the impact of dehydration of sandstones on complex conductivity spectra. Spectral induced polarization measurements were performed on five sandstone samples during evaporative drying. The complex conductivity spectra indicate considerable changes with decreasing saturation. The relationship between conductivity and saturation can be described by a power law known as the second empirical Archie equation. Separate saturation exponents have been determined for the real and imaginary parts of conductivity. The imaginary part of conductivity indicates higher saturation exponents for the investigated sandstones compared to the real part. Obviously, the saturation exponents depend on the method used for changing water saturation. Evaporative drying, which is used in our experiments, causes an increase of pore-water salinity and results in lower saturation exponents for the real part of conductivity but higher exponents for the imaginary part in comparison with the classical imbibition/drainage technique. We evaluate a theoretical approach that considers the influence of pore water salinity on the saturation exponents of the real and imaginary parts of conductivity. The complex conductivity spectra are processed by a Debye decomposition procedure. The resulting integrating parameters such as direct current resistivity, total chargeability, normalized chargeability, and mean relaxation time indicate a power law dependence on saturation. Our experiments indicate that the imaginary part of conductivity and normalized chargeability have a high sensitivity related to the drying process of rocks and might be suitable indicators to monitor the changes of moisture content in sandstones.

Impact of Inoculation Protocols, Salinity, and pH on the Degradation of Polycyclic Aromatic Hydrocarbons (PAHs) and Survival of PAH-Degrading Bacteria Introduced into Soil

1998 ◽  
Vol 64 (1) ◽  
pp. 359-362 ◽  
Author(s):  
Matthias Kästner ◽  
Maren Breuer-Jammali ◽  
Bernd Mahro
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Pore Water ◽  
Aromatic Hydrocarbons ◽  
Soil Bacteria ◽  
Water Salinity ◽  
Sphingomonas Paucimobilis ◽  
Pah Degradation ◽  
Degrading Bacteria ◽  
Polycyclic Aromatic ◽  
Pore Water Salinity

ABSTRACT Degradation of polycyclic aromatic hydrocarbons (PAHs) and survival of bacteria in soil was investigated by applying different inoculation protocols. The soil was inoculated with Sphingomonas paucimobilis BA 2 and strain BP 9, which are able to degrade anthracene and pyrene, respectively. CFU of soil bacteria and of the introduced bacteria were monitored in native and sterilized soil at different pHs. Introduction with mineral medium inhibited PAH degradation by the autochthonous microflora and by the strains tested. After introduction with water (without increase of the pore water salinity), no inhibition of the autochthonous microflora was observed and both strains exhibited PAH degradation.

Distribution of saline permafrost in the Northwest Territories, Canada

1993 ◽  
Vol 30 (3) ◽  
pp. 506-514 ◽  
Author(s):  
E.G. Hivon ◽  
D.C. Sego
Keyword(s):  
Key Words ◽  
Data Base ◽  
Northwest Territories ◽  
Pore Water ◽  
Coastal Communities ◽  
Quaternary Geology ◽  
Water Salinity ◽  
Mackenzie Delta ◽  
Pore Water Salinity ◽  
Detrimental Impact

Saline permafrost has a detrimental impact on the performance of foundations. Increased pore-water salinity decreases the strength and increases the deformation susceptibility of permafrost and foundations installed in permafrost. A data base of the distribution of saline permafrost in the Northwest Territories shows high pore-water salinities beneath coastal communities and at locations along the upper Mackenzie Valley and within the Mackenzie Delta. Salinity of inland sites is usually low. High salinities are usually associated with ice-poor materials and are linked with previous marine submergence associated with glacial events. Key words : permafrost, saline distribution, measurements, Quaternary geology.

Effects of pore-water salinity on soil identification using in situ cone penetration tests

2021 ◽  
pp. 106252
Author(s):  
Yongfeng Deng ◽  
Haochen Xue ◽  
Yongxin Wu ◽  
Tongwei Zhang ◽  
Zilong Wu ◽  
...  
Keyword(s):  
Pore Water ◽  
Water Salinity ◽  
Cone Penetration ◽  
Cone Penetration Tests ◽  
Pore Water Salinity ◽  
Penetration Tests

Segregation potential – pressure – salinity relationships near thermal steady state for a clayey silt

1990 ◽  
Vol 27 (2) ◽  
pp. 203-215 ◽  
Author(s):  
J.-M. Konrad
Keyword(s):  
Steady State ◽  
Pore Water ◽  
Moisture Transfer ◽  
Frost Heave ◽  
Water Salinity ◽  
Saline Soils ◽  
Clayey Silt ◽  
Segregation Potential ◽  
Pore Water Salinity ◽  
Thermal Steady State

Laboratory freezing tests were performed on a saturated clayey silt at various pore-water salinities and applied pressures to establish the relationships between pore-water salinity, overburden, and the amount of moisture transfer during freezing near thermal steady state conditions. The experimental data confirmed that the concept of segregation potential established for salt-free soils can be extended to saline soils. The segregation potential at the onset of the final ice lens in step-freezing tests (or near thermal steady state) should be related to the average salinity of the frozen fringe associated with the final ice lens. This pore-water salinity is different from the initial pore-water salinity as a result of solute exclusion at the ice lenses causing an enrichment as freezing proceeds. Unfortunately, it is very difficult to determine the average salinity in the frozen fringe owing to its small size. Instead, it is proposed to use the initial water salinity to develop the constitutive equations in freezing saline soils. A procedure for frost heave predictions in the field is outlined. Key words: freezing tests, clayey silt, saline water, frost heave.

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