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Measuring dielectric constant in highly conductive soils based on surface reflection coefficients / Renpeng Chen in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N° 12 (Décembre 2009) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 12 (Décembre 2009) . - pp. 1883–1891 Titre : Measuring dielectric constant in highly conductive soils based on surface reflection coefficients Type de document : texte imprimé Auteurs : Renpeng Chen, Auteur ; Wei Xu, Auteur ; Yunmin Chen, Auteur Année de publication : 2010 Article en page(s) : pp. 1883–1891 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Soil  propertiesElectrical  conductivityCoefficientsReflection Résumé : In soils with high electrical conductivities, time domain reflectometry (TDR) principles fail to measure the apparent dielectric constant by travel time analysis. This limits the application of water content measurement of existing TDR technologies on those materials. This paper describes a new approach for determining the dielectric constants in highly conductive soils from surface reflections of TDR signals. The multiple reflections at the interfaces of impedance mismatches in the ASTM standard probe were studied. Extension rods were used to avoid the overlap of the reflections along the probe. A relationship between the reflection coefficient at the soil surface and the apparent dielectric constant of the soil was established theoretically and validated by laboratory experiments. Results indicate that the dielectric constant can be determined with reasonable accuracy from the surface reflection coefficient even for soils with high electrical conductivities, where the conventional travel time analysis fails. Compared with alternative approaches, such as based on inversion model, this new method offers high time efficiency in extending TDR applications in highly conductive soils. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000170 [article] Measuring dielectric constant in highly conductive soils based on surface reflection coefficients [texte imprimé] / Renpeng Chen, Auteur ; Wei Xu, Auteur ; Yunmin Chen, Auteur . - 2010 . - pp. 1883–1891. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 12 (Décembre 2009) . - pp. 1883–1891 Mots-clés : Soil  propertiesElectrical  conductivityCoefficientsReflection Résumé : In soils with high electrical conductivities, time domain reflectometry (TDR) principles fail to measure the apparent dielectric constant by travel time analysis. This limits the application of water content measurement of existing TDR technologies on those materials. This paper describes a new approach for determining the dielectric constants in highly conductive soils from surface reflections of TDR signals. The multiple reflections at the interfaces of impedance mismatches in the ASTM standard probe were studied. Extension rods were used to avoid the overlap of the reflections along the probe. A relationship between the reflection coefficient at the soil surface and the apparent dielectric constant of the soil was established theoretically and validated by laboratory experiments. Results indicate that the dielectric constant can be determined with reasonable accuracy from the surface reflection coefficient even for soils with high electrical conductivities, where the conventional travel time analysis fails. Compared with alternative approaches, such as based on inversion model, this new method offers high time efficiency in extending TDR applications in highly conductive soils. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29GT.1943-5606.0000170

Short-term electrical conductivity and strength development of lime kiln dust modified soils / Renpeng Chen in Journal of geotechnical and geoenvironmental engineering, Vol. 135 N° 4 (Avril 2009) 

Public ISBD [article]  in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 4 (Avril 2009) . - pp. 590–594 Titre : Short-term electrical conductivity and strength development of lime kiln dust modified soils Type de document : texte imprimé Auteurs : Renpeng Chen, Auteur ; Vincent P. Drnevich, Auteur ; Radha Krishna Daita, Auteur Année de publication : 2009 Article en page(s) : pp. 590–594 Note générale : Geotechnical and geoenvironmental engineering Langues : Anglais (eng) Mots-clés : Dust  Electrical  conductivity  Penetration  resistance  Clays Résumé : Lime kiln dust (LKD) is used for modifying pavement subgrades to expedite construction on wet clayey soils. This paper describes the short-term development (typically, over the first 3to7days ) of electrical conductivity and penetration resistance of LKD-modified soils. The normalized net change of electrical conductivity is solely related to the LKD dosage. The decrease of electrical conductivity with time coincides with the increase of penetration resistance with time. The correlations of electrical conductivity with strength gain in LKD and lime-modified soils suggest that electrical conductivity measurements can potentially be useful for quality control in field applications. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282009%29135%3A4%2859 [...] [article] Short-term electrical conductivity and strength development of lime kiln dust modified soils [texte imprimé] / Renpeng Chen, Auteur ; Vincent P. Drnevich, Auteur ; Radha Krishna Daita, Auteur . - 2009 . - pp. 590–594. Geotechnical and geoenvironmental engineering Langues : Anglais (eng) in Journal of geotechnical and geoenvironmental engineering > Vol. 135 N° 4 (Avril 2009) . - pp. 590–594 Mots-clés : Dust  Electrical  conductivity  Penetration  resistance  Clays Résumé : Lime kiln dust (LKD) is used for modifying pavement subgrades to expedite construction on wet clayey soils. This paper describes the short-term development (typically, over the first 3to7days ) of electrical conductivity and penetration resistance of LKD-modified soils. The normalized net change of electrical conductivity is solely related to the LKD dosage. The decrease of electrical conductivity with time coincides with the increase of penetration resistance with time. The correlations of electrical conductivity with strength gain in LKD and lime-modified soils suggest that electrical conductivity measurements can potentially be useful for quality control in field applications. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282009%29135%3A4%2859 [...]