Estimation of dielectric permittivity, water content, and porosity for environmental engineering and hydrogeological studies using ground penetrating radar, a short review

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.

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Fault Detection with Crosshole and Reflection Geo-Radar for Underground Mine Safety

Geosciences ◽

10.3390/geosciences10110456 ◽

2020 ◽

Vol 10 (11) ◽

pp. 456

Author(s):

Jakob Kulich ◽

Florian Bleibinhaus

Keyword(s):

Dielectric Permittivity ◽

Fault Detection ◽

Water Content ◽

Ground Penetrating Radar ◽

Underground Mine ◽

Mine Safety ◽

Reflection Mode ◽

Ore Bodies ◽

Ground Penetrating ◽

Borehole Imaging

Ground-penetrating radar and crosshole radar are applied in an underground marble mine for fault detection and to test if different geological bodies can be distinguished. Boreholes are often drilled in advance of mining to clarify the locations of ore bodies and gangues. Here, such boreholes were used for crosshole investigations to supplement optical borehole imaging. Four boreholes were drilled along a profile with increasing offsets from 5 to 25 m. The crosshole measurements were performed with 100 MHz antennas. Tomographic panels were created up to a depth of 28 m and were complemented by reflection mode ground-penetrating radar (GPR) measurements along a 25 m-long profile with 100 and 250 MHz antennas. The GPR imaging successfully delineates the fault and karstification zones with higher water content due to their strong dielectric permittivity contrast compared to the surrounding geology.

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Correction to “Complex dielectric permittivity measurements from ground-penetrating radar data to estimate snow liquid water content in the pendular regime”

Water Resources Research ◽

10.1029/2009wr008959 ◽

2010 ◽

Vol 46 (2) ◽

Cited By ~ 2

Author(s):

John H. Bradford ◽

Joel T. Harper ◽

Joel Brown

Keyword(s):

Dielectric Permittivity ◽

Water Content ◽

Liquid Water ◽

Ground Penetrating Radar ◽

Liquid Water Content ◽

Radar Data ◽

Complex Dielectric Permittivity ◽

Ground Penetrating ◽

Permittivity Measurements

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Soil Water Content Estimation Using High-Frequency Ground Penetrating Radar

Water ◽

10.3390/w11051036 ◽

2019 ◽

Vol 11 (5) ◽

pp. 1036 ◽

Cited By ~ 4

Author(s):

Ligang Zhou ◽

Dongsheng Yu ◽

Zhaoyan Wang ◽

Xiangdong Wang

Keyword(s):

Dielectric Permittivity ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

High Precision ◽

Ground Penetrating Radar ◽

High Frequency ◽

Loamy Sand ◽

Silty Loam ◽

Ground Penetrating

The rapid high-precision and nondestructive determination of shallow soil water content (SWC) is of vital importance to precision agriculture and water resource management. However, the low-frequency ground penetrating radar (GPR) technology currently in use is insufficient for precisely determining the shallow SWC. Therefore, it is essential to develop and use a high-precision detection technology to determine SWC. In this paper, a laboratory study was conducted to evaluate the use of a high-frequency GPR antenna to determine the SWC of loamy sand, clay, and silty loam. We collected soil samples (0–20 cm) of six soil types of loamy sand, clay, and silty loam and used a high-frequency (2-GHz) GPR antenna to determine the SWC. In addition, we obtained GPR data and images as well as characteristic parameters of the electromagnetic spectrum and analyzed the quantitative relationship with SWC. The GPR reflection two-way travel times and the known depths of reflectors were used to calculate the average soil dielectric permittivities above the reflectors and establish a spatial relationship between the soil dielectric permittivity ( ε ) and SWC ( θ ), which was used to estimate the depth-averaged SWC. The results show that the SWC, which affects the attenuation of wave energy and the wave velocity of the GPR signal, is a dominant factor affecting the soil dielectric permittivity. In addition, the conductivity, magnetic soil, soil texture, soil organic matter, and soil temperature have substantial effects on the soil dielectric permittivity, which consequentially affects the prediction of SWC. The correlation coefficients R2 of the “ θ ~ ε ” cubic curve models, which were used to fit the relationships between the soil dielectric permittivity ( ε ) and SWC ( θ ), were greater than 0.89, and the root-mean-square errors were less than 2.9%, which demonstrate that high-frequency GPR technology can be applied to determine shallow SWC under variable hydrological conditions.

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