Discovery Park Undergraduate Research Internship Program

"New Generation TDR for Water Content and Dry Density of Soils"

About the Project

Project Time & Type:
Spring 2013 - DURI
Research area(s):
Civil Engineering - Soil Properties, Electrical Engineering - E&M
Project Description:
This research involves a new methodology for determining soil water content and density under different compaction energies and soil temperatures using time domain reflectometry (TDR) which involves propagation of electromagnetic waves through soil. A new calibration equation was introduced which allows for the direct calculation of dry density from measured electromagnetic waveforms. Values of dry density are then used in the normalized apparent dielectric constant equation to determine the water content. Results of numerous laboratory tests on a wide variety of soils (including coarse grained soils) showed that the proposed method accommodates different levels of compaction energy. The method also was validated with different field tests at sites commonly used in geotechnical earthwork construction, using soil-specific model coefficients determined from laboratory compaction tests. The results of this study indicate that the new calibration relationships appear relatively independent of the effects of compaction energy and of probe configuration in TDR testing. Because electromagnetic properties are temperature dependent, adjustments are made to the measured parameters for temperature of the soil. The proposed method presents an improvement to the “One-step” TDR method (ASTM D6780-05), a provisional patent for it has been filed, updating of the ASTM Standard is in the balloting process, and discussions on commercial licensing are taking place.
Expected Student Contributions:
The specific tasks for the DURI student will be to incorporate algorithms developed in this research to existing data acquisition and analysis software, PMTDR, for use in engineering practice. The student will need to be competent in Visual Basic or similar programming language and refining graphical user interfaces in the existing program. The algorithms are in the form of mathematical functions which must be translated for use in the existing program and their parameters determined through the application of optimization processes. Professors Drnevich and Krogmeier will be the primary contacts for the student.
Related Website(s):
Desired Qualifications:
Basic ability to program in Visual Basic and/or C.
Estimated Weekly Hours:
Department awards independent research credits for this project?
Yes, 3 credit hours

Professor in Charge

Krogmeier, James
electrical and computer engineering

Student Supervisor

Vincent P. Drnevich
Professor Emeritus

Cooperating Faculty

Vincent P. Drnevich
Civil and Environmental Engr./Engineering