Evaluation of Water Content in an Active Layer Using Penetration-Type Time Domain Reflectometry
Autor: | Seung Seo Hong, Jong Sub Lee, Sang Ho Lee, Won Taek Hong, Keunbo Park, Yong-Hoon Byun |
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Rok vydání: | 2018 |
Předmět: |
Materials science
Soil test 0208 environmental biotechnology active layer Soil science 02 engineering and technology Dielectric lcsh:Technology time domain reflectometry (TDR) lcsh:Chemistry Electrical resistivity and conductivity General Materials Science Reflectometry lcsh:QH301-705.5 Instrumentation Water content water content Fluid Flow and Transfer Processes Moisture lcsh:T Process Chemistry and Technology General Engineering 04 agricultural and veterinary sciences lcsh:QC1-999 020801 environmental engineering Computer Science Applications Active layer lcsh:Biology (General) lcsh:QD1-999 lcsh:TA1-2040 Soil water 040103 agronomy & agriculture 0401 agriculture forestry and fisheries lcsh:Engineering (General). Civil engineering (General) lcsh:Physics electrical resistivity |
Zdroj: | Applied Sciences, Vol 8, Iss 6, p 935 (2018) Applied Sciences Volume 8 Issue 6 |
ISSN: | 2076-3417 |
Popis: | The moisture condition of the active layer in Arctic regions can induce severe problems, such as ground subsidence and frost heave. Thus, the water content in the active layer needs to be estimated using a light and portable in-situ testing device. In this study, a penetration-type time domain reflectometry (PTDR) device is developed for the estimation of volumetric water content in the active layer. The developed PTDR is applied at a site for an electrical resistivity survey to characterize the water distribution along a measurement line. A PTDR consists of a PTDR module, connecting rods, and a guide with a hammer. The PTDR module can determine the dielectric constant of a material from the measurement of the travel time of electromagnetic waves. Using remolded soil samples, the dielectric constants measured from the PTDR are calibrated with the volumetric water content. The PTDR calibration demonstrates that the dielectric constant increases with the water content. For the temperature of 0.1 to 15.2 ° C, the travel time only slightly depends on the temperature variance. For field application, a PTDR is pressed into the ground and measures the electromagnetic waves and temperature with depth. The results of the field tests show that the volumetric water content measured by the PTDR increases with depth due to the impermeable layer located underneath the active layer. The electrical resistivity survey conducted at the same site provides the electrical resistivity profile for a long distance and shallow depth soils. Furthermore, the electrical resistivity survey and PTDR establish a significant correlation between electrical resistivity and water content. The PTDR developed in this study can be effectively used as an advanced in-situ testing method to estimate the water distribution in the active layer. |
Databáze: | OpenAIRE |
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