scholarly journals Relation between relative dielectric permittivity and volumetric water content with dielectric dispersion of soil samples

2011 ◽  
Vol 64 (3) ◽  
pp. 177-186 ◽  
Author(s):  
Keiichi Suzuki
Keyword(s):  
Dielectric Permittivity ◽  
Water Content ◽  
Dielectric Dispersion ◽  
Soil Samples ◽  
Volumetric Water Content ◽  
Relative Dielectric Permittivity

scholarly journals Performance of Soil Water Content Using Ground Penetrating Radar with Different Antenna Frequencies

2018 ◽  
Vol 7 (2.29) ◽  
pp. 815
Author(s):  
Nurul Izzati Abd Karim ◽  
Samira Albati Kamaruddin ◽  
Rozaimi Che Hasan
Keyword(s):  
Dielectric Permittivity ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Ground Penetrating Radar ◽  
Peat Soil ◽  
Relative Dielectric Permittivity ◽  
Depth Of Penetration ◽  
Engineering Research ◽  
Ground Penetrating

Accurate measurements of Soil Water Content (SWC) with applicable and relevant support are essential in many fields of earth and soil engineering research. Ground Penetrating Radar (GPR) is a geophysical tool that measures and provides accurate results for determination of the SWC. To prove the accuracy of SWC measurement using GPR, a field survey was performed in peat soil. This paper presents a fieldwork survey with the aim of assessing the SWC measurement using GPR. The survey work was conducted at Johor Bharu using different antenna frequencies (250 and 700 MHz). Five profiles, which is 5m by 5m in length, were scanned along an east-west direction with a common offset at an equal spacing of 1m.  To measure the SWC using GPR, the researchers used the velocity from the GPR’s signal from the receiving antenna to the soil. Statistical analysis was carried out based on the dielectric permittivity and SWC. Schaap’s equation and Roth’s equation were used to distinguish the relative dielectric permittivity of the soil to SWC. The results of this study show the linear function,  for the measured SWC. The validation graph shows that at a frequency of 250 MHz, the depth of penetration was greater compared to the frequency of 750 MHz. These results, suggest that a higher frequency will give higher resolution but lower depth penetration.  

scholarly journals Measurement of Volumetric Water Content by Gravimetric and Time Domain Reflectometry Methods at Field Experiment with Biochar and N Fertilizer

2019 ◽  
Vol 22 (2) ◽  
pp. 61-64 ◽  
Author(s):  
Lucia Toková ◽  
Dušan Igaz ◽  
Elena Aydin
Keyword(s):  
Field Experiment ◽  
Water Content ◽  
Time Domain ◽  
Soil Property ◽  
Time Domain Reflectometry ◽  
Soil Samples ◽  
Volumetric Water Content ◽  
N Fertilizer ◽  
High Concentration ◽  
Indirect Methods

Abstract There are many methods used for soil water content measurement which we can divide into direct gravimetric methods from using soil samples or indirect methods that are based on the measurement of another soil property which is dependent on soil moisture. The paper presents the findings of volumetric water content measurements with gravimetric and time domain reflectometry (TDR) methods. We focused on four variants in the field experiment in Dolná Malanta (Slovakia): control variant (B0+N0), variant with biochar at dose 20 t.ha−1 without N fertilizer (B20+N0), variant with biochar 20 t.ha−1 and N fertilizer 160 kg.ha−1 (B20+N160) and variant with biochar 20 t.ha−1 and N fertilizer 240 kg.ha−1 (B20+N240). TDR is nowadays a well-established dielectric technique to measure volumetric water content; however, its accuracy is influenced by high concentration of salts in soil. In this paper, we evaluated the effect of added N fertilizer on the measuring accuracy of HydroSense II device that is operating under the TDR principle.

scholarly journals Evaluating the maximum shear modulus (G0) for different bender-soil coupling loads

2020 ◽  
Vol 195 ◽  
pp. 03007
Author(s):  
Caio de Mattos Azevedo de Paula ◽  
Thiago de Souza Carnavale
Keyword(s):  
Shear Modulus ◽  
Water Content ◽  
Unsaturated Soils ◽  
Granite Gneiss ◽  
Soil Samples ◽  
Volumetric Water Content ◽  
Current Paper ◽  
Bender Elements ◽  
Cylindrical Samples

The current paper aims to test the effects of vertical loads on the maximum shear modulus (G0). The tests were undertaken with unsaturated soils in unconfined conditions. As a material, was used a set of granite-gneiss soil samples collected in the Quinta do Paraiso Campus, at the Centro Universitário Serra dos Órgãos (UNIFESO), Teresópolis – Brazil. To perform it, cylindrical samples were submitted to bender elements under four vertical loads (200 g, 400 g, 500 g, and 600 g). Further, the readings were done with the same amplitude and frequency values. The results revealed a decrease in the shear wave’s velocity reducing the volumetric water content. Besides, the shear modulus increased with the vertical loads’ addition.

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.

Measuring duff moisture content in the field using a portable meter sensitive to dielectric permittivity

2004 ◽  
Vol 13 (3) ◽  
pp. 343 ◽  
Author(s):  
P. R. Robichaud ◽  
D. S. Gasvoda ◽  
R. D. Hungerford ◽  
J. Bilskie ◽  
L. E. Ashmun ◽  
...  
Keyword(s):  
Dielectric Permittivity ◽  
Water Content ◽  
Forest Cover ◽  
Volumetric Water Content ◽  
Moisture Meter ◽  
Sample Chamber ◽  
Frequency Domain Reflectometry ◽  
Forest Cover Types ◽  
Gravimetric Water Content ◽  
Best Fit

Duff water content is an important consideration for fire managers when determining favourable timing for prescribed fire ignition. The duff consumption during burning depends largely on the duff water content at the time of ignition. A portable duff moisture meter was developed for real-time water content measurements of non-homogenous material such as forest duff. Using circuitry developed from time and frequency domain reflectometry (TDR and FDR) technologies, this sensor measures a change in frequency that is responsive to the dielectric permittivity of the duff material placed in a sample chamber and compressed. Duff samples from four forest cover types—Douglas fir, larch, lodgepole pine and spruce/alpine fir—were used to calibrate the frequency output to volumetric water content. A second-order polynomial (R2 = 0.97) provides the best fit of the data to volumetric water content. The accuracy of the duff moisture meter is ±1.5% at 30% volumetric water content and ±4% at 60% volumetric water content. The volumetric water content can readily be converted to gravimetric water content, which is used more frequently by fire managers and as an input to predictive models of duff consumption.

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