Dielectric relaxation behavior of Callovo‐Oxfordian clay rock: A hydraulic‐mechanical‐electromagnetic coupling approach

Wagner, Norman; Boré, Thierry; Robinet, Jean-Charles; Coelho, D.; Taillade, Frédéric; Delépine-Lesoille, Sylvie

doi:10.1002/jgrb.50343

Cited by 49 publications

(46 citation statements)

References 89 publications

(180 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some of the results of the CDP measurement in the wide frequency band are given in works in [1,2]. A number of researches [3][4][5][6][7][8][9] give evidence of the CDP hysteresis phenomenon existence.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic Waves Attenuation in the Sandstones With Grains of Different Size at Imbibition and Drying

Бобров¹

2016

PIER M

View full text Add to dashboard Cite

Abstract-The results of experimental measurements of the complex dielectric permittivity (CDP) of powders of quartz granules with different sizes saturated with water and salt solution of weak concentration are given in the frequency band from 20 kHz to 1 GHz. It is shown that at values of saturation level from 0.6 to 0.9 the relaxation phenomena caused by interfacial polarization on the water-air bound can be observed. The result shows considerable reduction of attenuation in gradually saturated rocks, which allows for deeper sensing during georadar mapping. It is determined that in the dielectric relaxation band and at frequencies below it the hysteresis of the real part of the CDP and equivalent specific conductivity can be observed. Its character significantly depends on the sizes of granules. It is shown that the behavior of CDP and attenuation of an electromagnetic wave at frequencies from 0.1 to 10 MHz complicatedly depends on the sizes of granules, saturation level, salinity of the saturating solution and saturation history.

show abstract

Section: Introductionmentioning

confidence: 99%

Electromagnetic Waves Attenuation in the Sandstones With Grains of Different Size at Imbibition and Drying

Бобров¹

2016

PIER M

View full text Add to dashboard Cite

show abstract

“…Furthermore, the contribution in the imaginary part at frequencies > 1 GHz (Fig. 4 (b)) due to reorientational polarization of water molecules in the aqueous pore solution with relaxation frequency > 10 GHz [33] is not considered. Despite this, we can see that (23) gives a satisfactory description on the dielectric behavior in the investigated frequency range.…”

mentioning

confidence: 99%

Broadband Dielectric Measurement Methods for Soft Geomaterials: Coaxial Transmission Line Cell and Open-Ended Coaxial Probe

Chen¹,

Schwing²,

Karlovšek³

et al. 2014

IJET

View full text Add to dashboard Cite

I. INTRODUCTIONDue to their intrinsic merits including non/less-invasive virtue and capability of automation and remote sensing, geophysical electromagnetic (EM) methods such as time domain reflectometry (TDR) [1] and ground penetrating radar (GPR) [2] have long been recognized as effective and practical methods in geomaterials characterization [3], [4]. Generally measuring time or frequency dependent EM properties of geomaterials as response to an applied EM field, EM methods are able to characterize geomaterials in terms of correlations between their EM properties and compositional and structural properties. Successful applications of EM methods in this regard have been massively witnessed since decades ago, among which the determination of water content of geomaterials is probably the most well-known one [5].Despite its great success, the application of EM methods in geomaterials characterization is still confronted with many theoretical and technical difficulties. Almost all geomaterials are heterogeneous systems composed of components with different physicochemical properties. Complex EM properties of some constituent components in addition to interface processes arising from the interaction between those components make the overall EM properties of most geomaterials extremely complicated. Theoretical consideration on their EM properties is greatly challenged by this complication because it is difficult to take all factors into account. However, carefully designed experimental studies are able to determine factors that dominate the EM properties of geomaterial at defined environments and thereby able to greatly simplify and/or optimize theoretical consideration. Experimental studies, especially in a broad frequency range, are also able to find out correlations between EM properties and other engineering parameters of geomaterials, which are practical in field investigation.On the other hand, EM properties of a geomaterial are generally affected by a great number of factors related to environmental parameters as well as its compositional and structural nature. For civil engineering purposes, it is intended to measure EM properties of geomaterials without disturbing their engineering nature. Optimized measurement protocol in combination with non-destructive sample cells is therefore highly desirable to this end. Open-ended coaxial probe (OC) has long been used as a non-destructive sample cell in the characterization of various materials including biological tissues [6], [7], liquids [8]-[10], and geomaterials [11]-[14]. Since the sample under test has to be fully contacted with the flat end of this type of probe, it is generally only suitable for soft materials or hard materials with ideally flat surface. In addition, due to the size of this type of probe, the effective measurement volume is normally limited to the order of cm 3 . A non-destructive two-port coaxial transmission line cell (CC) recently developed by Lauer et al. [15] is able to measure a larger sample volume but still keep the sample undistur...

show abstract

“…The parameters ε ⋆ r , µ ⋆ r , and σ ⋆ E are generally a secondorder tensor with nine independent material parameters [140]. However, quasi-isotropy is assumed at the sample scale [141].…”

Section: Constitutive Equationsmentioning

confidence: 99%

“…The relative permittivity of the solid phase in the case of mineral grains is considered not frequency or temperature dependent in the investigated T, f -range [140]. Thus, the relative permittivity of the solid phase is considered a constant real number, and found to be in the value range between 3 to 15 [19,175].…”

Section: Solid Phasementioning

confidence: 99%

“…The relaxation time, τ FW (T ), of pure water dependent on the temperature, T , can be approached by the following expression [191]: Free water in fine-grained soils is not subject to binding forces to the particle surface, and the water phase is seen as an aqueous solution with a certain ion concentration that not only causes dielectric losses, but also contributes to the direct current conductivity [140].…”

Section: Free Water Phasementioning

confidence: 99%

See 1 more Smart Citation

Mechanical, hydraulic, and dielectric characterisation of fine-grained soils during densification

Schwing¹

View full text Add to dashboard Cite

Soil characterisation is of primary interest for several disciplines, including geotechnical and geo-environmental engineering, soil science, and agriculture. An upcoming and promising method for soil characterisation relies on the high-frequency electromagnetic measurement technique which provides the potential to explore and investigate soils. However, successful application of this technique requires a profound understanding of the multi-physical processes arising from interactions between soil as a porous medium and the propagation of electromagnetic waves. This thesis focuses on a coupled experimental investigation of the mechanical, hydraulic, and dielectric characterisation of fine-grained soil during densification.In the framework of this thesis, the following steps have been completed and novel findings have been made:1. Probe designs have been developed, modified and improved to measure the dielectric soil properties in a frequency range from 1 MHz to 3 GHz during shrinkage and compaction. A low-cost in-house-manufactured probe was introduced, which was specifically designed for standardised geotechnical soil shrinkage test. During preliminary investigations, the calibration procedure and performance of these sensors were experimentally and numerically tested. The results showed agreement in the targeted frequency window.2. Compaction and shrinkage tests on fine-grained soils were conducted in combination with dielectric and soil suction measurements. The shrinkage curve and soil water characteristic curve (SWCC) was established and successfully parameterised with physical based models. The complex permittivity was determined in a frequency range from 1 MHz to 3 GHz. The dielectric properties measured during the shrinkage test showed a sudden drop of complex permittivity which could be located in the residual shrinkage zone.3. A theoretical electromagnetic mixture approach was used to model the measured frequency dependent dielectric properties of soils during shrinkage and compaction based on the parameterised shrinkage curve and SWCC. The theoretical results were compared to the dielectric measurements on different fine-grained soils. The comparison ii showed that the real part of permittivity could be well predicted whereas the imaginary part suffered inaccuracies.4. A sensitivity analysis was performed with the theoretical electromagnetic mixture approach in consideration of the shrinkage behaviour and SWCC in order to investigate the influence of soil suction and dry density on the frequency dependent permittivity.The sensitivity analysis showed that the real part of the permittivity near 1 GHz was insensitive to changes in the soil suction and dry density. In the MHz range, the real part of the permittivity was more sensitive to changes in soil suction than it was to dry density. The imaginary part of the permittivity was generally observed to be more sensitive to soil suction over the entire frequency range.

show abstract

Dielectric relaxation behavior of Callovo‐Oxfordian clay rock: A hydraulic‐mechanical‐electromagnetic coupling approach

Cited by 49 publications

References 89 publications

Electromagnetic Waves Attenuation in the Sandstones With Grains of Different Size at Imbibition and Drying

Electromagnetic Waves Attenuation in the Sandstones With Grains of Different Size at Imbibition and Drying

Broadband Dielectric Measurement Methods for Soft Geomaterials: Coaxial Transmission Line Cell and Open-Ended Coaxial Probe

Mechanical, hydraulic, and dielectric characterisation of fine-grained soils during densification

Contact Info

Product

Resources

About