Soil mositure determination by frequency and time domain techniques
Previous research has shed light on using attenuation of an electrical signal to determine the water content of soils. A majority of this research has focused on using the time domain to analyze the results. This research looks at using the frequency domain to determine the moisture content of several different soils. The research employs a 100 MHz probe designed for full size cone penetrometer use. A range of coarse sands to fine clays were tested with the probe. The data collected from each soil was analyzed for its individual characteristics and test reproducibility. The probe's resiliency against the effect of ionic conductivity was analyzed in a sand based mixture. The compaction of the soil was also briefly investigated for its effects on the probe. The research produced results that allowed the probe to be defined as a reliable way to measure soil moisture. The results were validated with the use of gravimetric and TDR moisture determination. Along with fore mentioned research, the effects of fine grained soils on TDR soil moisture measurements were also investigated. Past research has shown that fine grained soils attenuate the TDR signal to the point where it makes it hard to determine the moisture content. With the use of a sand-clay mixture, strong attenuation that fine grained soils exhibit on TDR measurements were studied. The results of this study proved that soil specific calibrations are a necessity, when working in fine grained soils in order to make use of TDR to determine soil moisture.
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:cone penetrometer probe s resiliency gravimetric
Date of Publication:01/01/1997