Title
Experimental Determination of TDR Calibration Relationship for Pyroclastic Ashes of Campania (Italy).
Abstract
Time domain reflectometry (TDR) is one of the most widely used techniques for indirect determination of soil volumetric water content (theta). TDR measures the relative dielectric constant (epsilon(r)) which, in a three-phase system like the soil, depends on water, air, and solid matrix dielectric constants. Since dielectric constant of water is much larger than the other two, epsilon(r) of bulk soil mainly depends on water content. In many cases, the application of TDR requires a specific calibration of the relationship theta(epsilon(r)) to get quantitatively accurate estimates of soil water content. In fact, the relationship theta(epsilon(r)) is influenced by various soil properties, such as clay content, organic matter content, bulk density, and aggregation. Numerous studies have shown that pyroclastic soils often exhibit a peculiar dielectric behavior. In Campania (Southern Italy) wide mountainous areas are covered by layered pyroclastic deposits of ashes (loamy sands) and pumices (sandy gravels), often involved in the triggering of landslides induced by rainwater infiltration. Reliable field measurements of water content of such soils are therefore important for the assessment of landslide risk. Hence, in this paper, the theta(epsilon(r)) relationship has been experimentally determined on samples of typical pyroclastic soil of Campania, collected around Sarno, reconstituted with different porosities. The aim of the study is to identify specific calibration relationships for such soils based not only on empirical approaches. In this respect, a three-phase dielectric mixing model with a variable exponent is introduced, and the variable value of the exponent is related to the different dielectric properties of bond and free water within the soil pores.
Year
DOI
Venue
2018
10.3390/s18113727
SENSORS
Keywords
Field
DocType
TDR calibration relationship,pyroclastic soil,dielectric constant,soil bulk density
Analytical chemistry,Mineralogy,Pyroclastic rock,Bulk density,Dielectric,Engineering,Calibration,Instrumentation
Journal
Volume
Issue
ISSN
18
11.0
1424-8220
Citations 
PageRank 
References 
1
0.41
0
Authors
3
Name
Order
Citations
PageRank
Giovanna Capparelli120.83
Gennaro Spolverino210.41
Roberto Greco353.40