A Time Domain Transmission Method for Determining the Dependence of the Dielectric Permittivity on Volumetric Water Content

2003 ◽  
Vol 2 (2) ◽  
pp. 186
Author(s):  
K. Masbruch ◽  
T. P. A. Ferré
2000 ◽  
Vol 37 (6) ◽  
pp. 1325-1331
Author(s):  
J LH Grozic ◽  
M E Lefebvre ◽  
P K Robertson ◽  
N R Morgenstern

Time domain reflectometry (TDR) can be used to determine the volumetric water content of soils. This note describes the utilization of a TDR miniprobe in triaxial testing. The TDR performance was examined with a series of tests that not only proved its reliability but also resulted in two empirical correlations. Using these correlations, the degree of saturation and volumetric water content during triaxial testing could be determined. The TDR was then put to use in a laboratory program designed to investigate the response of loose gassy sand under static and cyclic loading. Because of the TDR measurements it was possible to determine the degree of saturation and void ratio of the gassy specimens. The TDR miniprobe proved to be accurate, simple to use, and inexpensive to build.Key words: time domain reflectometry, TDR, triaxial testing, gassy, unsaturated.


2019 ◽  
Vol 22 (2) ◽  
pp. 61-64 ◽  
Author(s):  
Lucia Toková ◽  
Dušan Igaz ◽  
Elena Aydin

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.


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