Dielectric permittivity of fine-grained fractions of soil samples from eastern Spain at 200 MHz

Geophysics ◽  
2010 ◽  
Vol 75 (1) ◽  
pp. J1-J9 ◽  
Author(s):  
Christina Salat ◽  
Andreas Junge
Keyword(s):  
Dielectric Permittivity ◽  
Water Content ◽  
Laboratory Data ◽  
Clay Fraction ◽  
Soil Samples ◽  
Small Scale ◽  
Carbonate Content ◽  
Dry Density ◽  
High Attenuation ◽  
Fine Grained

To provide a database for interpreting GPR field data by means of small-scale laboratory studies, we have determined the real and imaginary parts of the dielectric permittivity of fine-grained fractions of soil samples from eastern Spain in the laboratory. We use the parallel-plate method in combination with an impedance analyzer and focus on the frequency of [Formula: see text]. The measurements are compared to physical properties such as volumetric water content, dry density, clay fraction, and carbonate content. The results show the well-known increase in dielectric permittivity with increasing water content, as presented in the literature; however, our values are systematically higher. This deviation may be caused by the exceptionally high carbonate content of the samples. We establish a basic relationship between dielectric permittivity and water content that is characteristic for soils in the research area. In addition to the dominating influence of water on permittivity, we find a correlation with dry density as well, which is linear for dry samples. Finally, we calculate the attenuation coefficients and find high attenuation for samples with high clay fraction, even at low water contents. A 1D model of the permittivity distribution is constructed from borehole data (water content and layer thickness) coincident with a GPR profile and from the laboratory data. The modeled GPR trace explains the observation and thus connects laboratory measurements to GPR data.

Microstructural Interpretation of Water Content and Dry Density Influence on the DC-Electrical Resistivity of a Fine-Grained Soil

2011 ◽  
Vol 34 (6) ◽  
pp. 103763
Author(s):  
L. D. Suits ◽  
T. C. Sheahan ◽  
Yves-Laurent Beck ◽  
Sérgio Palma Lopes ◽  
Valéry Ferber ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Water Content ◽  
Dry Density ◽  
Dc Electrical Resistivity ◽  
Fine Grained ◽  
Fine Grained Soil

scholarly journals Freezing–Thawing Behavior of Lime Treated Fine–grained Soil

2018 ◽  
Vol 7 (4) ◽  
pp. 75
Author(s):  
Abdulrahman Aldaood ◽  
Amina Khalil ◽  
Marwen Bouasker ◽  
Muzahim Al-Mukhtar
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Unconfined Compressive Strength ◽  
Soil Samples ◽  
Treated Soil ◽  
Freeze Thaw ◽  
Fine Grained ◽  
Mineralogical Properties ◽  
Fine Grained Soil ◽  
The Impact

This research study was carried out to investigate the impact of freeze-thaw cycles on the mechanical and the mineralogical properties of lime treated fine-grained soil. The unconfined compressive strength, wave velocity, volume change, water content, pH and electrical conductivity values were determined during freeze-thaw cycles. Furthermore, Mercury porosimetry and X-ray diffraction tests were carry out to determine changes at microscopic level. The soil used in this study was taken at a site near Jossigny region in eastern part of Paris–France. The soil samples were treated with optimum lime percent 3% depending on the pH method, then cured for 28 days at 20 °C. The soil samples were subjected to 12 cycles of freeze-thaw following ASTM procedure.    The result referred that, natural soil exhibit no strength resistance against freeze-thaw cycles and failed during the first hours of freeze-thaw cycles. Analyses indicated that freeze-thaw cycles reduce the unconfined compressive strength of all the tested samples. Moreover, water content during the applied cycles increases and induces significant volume changes. During freeze-thaw cycles, the cracks propagation which caused by the formation of ice lenses in the pores of lime treated soil samples were consider to have significant. The changes in the micro-structural and mineralogical properties reduce the durability  of the lime treated soil samples when subjected to freeze-thaw cycles.

scholarly journals A Correlation between Compaction Characteristics and Soil Index Properties for Fine-grained Soils

2019 ◽  
Vol 9 (2) ◽  
pp. 93-99
Author(s):  
Hunar F. Hama Ali ◽  
Ahmed J. Hama Rash ◽  
Madeh I. Hama kareem ◽  
Daban A. Muhedin
Keyword(s):  
Soil Properties ◽  
Liquid Limit ◽  
Optimum Moisture Content ◽  
Soil Samples ◽  
Dry Density ◽  
Index Properties ◽  
Plastic Limit ◽  
Maximum Dry Density ◽  
Compaction Characteristics ◽  
Fine Grained

This paper addresses the correlation between the liquid and/or plastic limits with the compaction characteristics, maximum dry density, and optimum moisture content (OMC), for fine-grained soils. In the previous studies, several attempts have been made to identify these two important parameters from other simple soil properties such as index soil properties. Some concluded that liquid limit shows a good correlation with compaction characteristics, while others observed that plastic limit does. In this work, many soil samples have been taken from various locations around Koya city and the required tests have been carried out. The results have been illustrated to identify whether soil index properties can correlate with the compaction characteristics. It is concluded that neither plastic limit nor liquid limit can provide an adequate correlation with maximum dry density and OMC. Contrary to the literature, liquid limit provides better correlations.

Measurement of soil-water characteristic curves for fine-grained soils using a small-scale centrifuge

2002 ◽  
Vol 39 (5) ◽  
pp. 1209-1217 ◽  
Author(s):  
R M Khanzode ◽  
S K Vanapalli ◽  
D G Fredlund
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Characteristic Curve ◽  
Small Scale ◽  
Characteristic Curves ◽  
Pressure Plate ◽  
Soil Water Characteristic Curve ◽  
Fine Grained ◽  
Soil Water Characteristic Curves ◽  
Plate Apparatus

Considerably long periods of time are required to measure soil-water characteristic curves using conventional equipment such as pressure plate apparatus or a Tempe cell. A commercially available, small-scale medical centrifuge with a swinging type rotor assembly was used to measure the soil-water characteristic curves on statically compacted, fine-grained soil specimens. A specimen holder was specially designed to obtain multiple sets of water content versus suction data for measuring the soil-water characteristic curve at a single speed of rotation of the centrifuge. The soil-water characteristic curves were measured for three different types of fine-grained soils. The three soils used in the study were processed silt (liquid limit, wL = 24%; plasticity index, Ip = 0; and clay = 7%), Indian Head till (wL = 35.5%, Ip = 17%, and clay = 30%), and Regina clay (wL = 75.5%, Ip = 21%, and clay = 70%). The soil-water characteristic curves for the above soils were measured in 0.5, 1, and 2 days, respectively, using the centrifuge technique for suction ranges from 0 to 600 kPa. Time periods of 2, 4–6, and 16 weeks were required for measuring the soil-water characteristic curves for the same soils using a conventional pressure plate apparatus. There is reasonably good agreement between the experimental results obtained by the centrifuge and the pressure plate methods. The results of this study are encouraging as soil-water characteristic curves can be measured in a reduced time period when using a small-scale centrifuge.Key words: unsaturated soils, soil-water characteristic curve, centrifuge technique, soil suction, matric suction, water content.

scholarly journals Effect of clay content on strength and permeability of plastic loess-cement

2019 ◽  
Vol 48 (2) ◽  
pp. 25-30
Author(s):  
Boriana Tchakalova
Keyword(s):  
Water Content ◽  
Soil Stabilization ◽  
Clay Fraction ◽  
Clay Content ◽  
Loess Soil ◽  
Liquid Limit ◽  
Engineering Properties ◽  
Natural Soil ◽  
Dry Density ◽  
Maximum Dry Density

Plastic soil-cement is a type of soil stabilization used for the treatment of natural soil to improve its engineering properties. It is a hardened material prepared by mixing soil and Portland cement at a water content higher than optimum, usually near the liquid limit, without compaction at optimum water content to maximum dry density. In Bulgaria, this soil stabilization technique has been applied in foundation works in collapsible loess ground in order to replace a part of the collapsible layer, to increase the bearing capacity of the soil base and/or to isolate the geoenvironment from migration of pollutants. The aim of the current paper is to examine the effect of the clay content of the loess soil on the strength and permeability of plastic loess-cement. Results from the investigation indicate that the mechanical and hydraulic properties of the plastic loess-cement highly depend on the presence of clay fraction.

scholarly journals Soil–Water Retention Curves Derived as a Function of Soil Dry Density

GeoHazards ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 3-19 ◽  
Author(s):  
Yulong Chen
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Unsaturated Soils ◽  
Water Retention ◽  
Matric Suction ◽  
Soil Samples ◽  
Volumetric Water Content ◽  
Proton Nuclear Magnetic Resonance ◽  
Dry Density ◽  
Soil Water Retention

The soil–water retention curves (SWRC) of soil plays a key role in unsaturated soil mechanics, which is a relatively new field of study having wide applications particularly in geotechnical and geo-environmental engineering. SWRCs were used to evaluate the ability of unsaturated soils to attract water with various water contents and matric suctions. Drying and wetting SWRCs for a sandy soil with different dry densities were studied in a laboratory. Proton nuclear magnetic resonance, image processing technology, and mercury intrusion porosimetry were used to characterize the microscopic mechanisms of pore size distribution in the soil. Soil–water retention in the soil samples was strongly dependent on the dry density. With zero matric suction, soil samples with a higher dry density had a lower initial volumetric water content. Volumetric water content changed at a slower rate when values of matric suction increased in soils with a higher dry density. Soil samples had residual matric suction and a larger air-entry value with a smaller slope of the SWRC when they had a higher density. Dry density change is mainly responsible for the large pores. The number of large pores decreased as dry density increased. As the dry density increased, the area of macropores occupying the largest portion decreased, while the area of mesopores and micropores increased. Minipores accounted for the smallest proportion of total area and they were nearly constant. The proportion of large diameter pores decreased relative to pores with small diameters in the tested soils. The total pore volume was lower for soil specimens that had larger dry densities, as compared to relatively loose specimens. There was hysteresis between the drying and wetting curves for all soil samples. Hysteresis decreased as the dry density of the soil increased. The different liquid–solid contact angle was the main factor causing hysteresis of SWRC.

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