Beta Testing Implementation of the Purdue Time Domain Reflectometry (TDR) Method for Soil Water Content and Density Measurement

Drnevich, Vincent P.; Yu, Xiong; Lovell, Janet

doi:10.5703/1288284313153

Cited by 10 publications

(10 citation statements)

References 7 publications

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“…The user interface is through the PMTDR program developed by Drnevich et al [ 20 ]. The software controls the TDR device and sets vertical and horizontal scales.…”

Section: Measuring Methodsmentioning

confidence: 99%

A New Non-Destructive TDR System Combined with a Piezoelectric Stack for Measuring Properties of Geomaterials

et al. 2016

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Dry density and water content are two important factors affecting the degree of soil compaction. Conventional methods such as the sand cone test and the plate load test are used to measure such properties for evaluating the degree of compaction and the stiffness of soil in the field. However, these tests are generally very time-consuming and are inherent with some errors depending on the operator (in particular for the sand cone test). Elastic modulus is an indicator to describe the stress-strain behavior of soil and in some cases is used as a design input parameter. Although a rod type TDR (Time Domain Reflectometry) system has been recently proposed to overcome some shortcomings of the conventional methods (particularly the sand cone test), it requires driving the probes into the ground, thus implying that it is still a time-consuming and destructive testing method. This study aims to develop a new non-destructive TDR system that can rapidly measure the dry density, water content, and elastic modulus of soil on the surface of compacted soil, without disturbing the ground. In this study, the Piezoelectric Stack, which is an instrument for measuring the elastic modulus of soil, has been added to the TDR system with a flat type probe, leading to a non-destructive TDR system that is capable of measuring the dry density, water content, and elastic modulus of soil. The new TDR system developed is light enough for an engineer to carry. Results of the standard compaction and TDR tests on sand showed that the dry densities and the moisture contents measured with the new TDR system were in good agreement with those measured with the standard compaction test, respectively. Consequently, it appears that the new TDR system developed will be very useful to advance the current practice of compaction quality control.

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“…The user interface is through the PMTDR program developed by Drnevich et al [ 20 ]. The software controls the TDR device and sets vertical and horizontal scales.…”

Section: Measuring Methodsmentioning

confidence: 99%

A New Non-Destructive TDR System Combined with a Piezoelectric Stack for Measuring Properties of Geomaterials

et al. 2016

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“…(b). The temperature correction was obtained from the following relation (Drnevich, Lovell, Tiskmack, Yu and Zhang ) for cohesionless soils:

K_{a, T^{\circ} C} = K_{a, T^{\circ} C} \cdot (0.97 + 0.0015 \cdot T_{test, T^{\circ} C}),

where K a is apparent relative permittivity, T test the field soil temperature (°C) and T °C the reference temperature at 20°C. Values of 81, 5.9 and 10.4 were measured for water, dry beads and HFE, respectively.…”

Section: Acquisition Processing and Data Analysismentioning

confidence: 99%

Time‐lapse laboratory tests to monitor multiple phases of DNAPL in a porous medium

Orlando

Palladini

2018

Near Surface Geophysics

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A B S T R A C TA soil contaminated by dense non-aqueous phase liquids generally exhibits variation of electrical permittivity and resistivity over time. In this paper, we relate photo images with results of electrical resistivity tomography, induced polarization tomography, and ground-penetrating radar survey in a laboratory-controlled test, where a cell, filled with grained-glass beads contaminated with HFE-7100 (hydrofluoroether) and under saturated conditions, was used. The aim was to find robust links between geophysical and physico-chemical parameters of a contaminated soil in order to reduce the ambiguities in data interpretation. The monitoring, conducted over 100 days, shows that each geophysical method may or may not be sensitive to the multiple phases of hydrofluoroether (pure, dissolved and gaseous phases) depending on the contaminant (chemical composition, fresh, mature, etc.) and on the host enviroment. We propose some empirical relationships that allow us to quantitatively monitor the water saturation variation induced by hydrofluoroether.The photo images confirm that the pure phase of hydrofluoroether changes over time, which is probably due to biological or/and chemical variation of the contaminant. Electrical resistivity tomography results appear to be sensitive to the vast amount of pure phase of the hydrofluoroether. Induced polarization, measured in the extremely low frequency range (<25 Hz), allows detecting the pure phase of the contaminant, probably due to the decrease of water permeability and chemical degradation of the compound over time. The ground-penetrating radar and time domain reflectometry methods based on measurements in very-high frequency and ultra-high frequency ranges are mainly sensitive to the water content and, as a consequence, to the replacement of water by pure and gaseous phases of hydrofluoroether.

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“…The probe was connected to TDR100 from Campbell Scientific via a RG 58 coaxial cable of 1.7m for TDR measurement. TDR waveforms for each soil specimen were recorded using PMTDR data acquisition program originally developed at the research group at Purdue University (Drnevich et al 2003). After the TDR measurement, the thermo-TDR probe was connected to a D.C. source BK Precision 17850B to generate a heat pulse in the center probe.…”

Section: Laboratory Evaluationmentioning

confidence: 99%

Development and Evaluation of a Thermo-TDR Probe

Yu¹,

Zhang

Pradhan

2014

Soil Behavior and Geomechanics

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In the design of shallow geothermal systems such as energy piles and ground source heat pumps, it is essential to have accurate characterization of soil thermal properties. In general practice, soil thermal properties are estimated from design charts or semi-empirical models developed in the middle of the last century. These methods do not consider site specific conditions and often result in inaccurate estimation. In this study, a thermo-TDR probe sensor was developed to accurately measure soil moisture content, density as well as thermal properties. The developed thermo-TDR probe was calibrated and tested for brown sand at different moisture content and density. The performance of the thermo-TDR probe was verified with a standard heat probe as well as model predictions. Results show the thermo-TDR probe can be very useful for thermal study of soils.

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Beta Testing Implementation of the Purdue Time Domain Reflectometry (TDR) Method for Soil Water Content and Density Measurement

Cited by 10 publications

References 7 publications

A New Non-Destructive TDR System Combined with a Piezoelectric Stack for Measuring Properties of Geomaterials

A New Non-Destructive TDR System Combined with a Piezoelectric Stack for Measuring Properties of Geomaterials

Time‐lapse laboratory tests to monitor multiple phases of DNAPL in a porous medium

Development and Evaluation of a Thermo-TDR Probe

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