Type of Document	Dissertation
Author	Liu, Ning
Author's Email Address	niliu1@vt.edu
URN	etd-04042007-182854
Title	Soil and Site Characterization Using Electromagnetic Waves
Degree	PhD
Department	Civil Engineering
Advisory Committee	Advisor Name Title James, K. Mitchell Committee Chair David A. de Wolf Committee Member George M. Filz Committee Member Matthew Mauldon Committee Member Thomas L. Brandon Committee Member
Keywords	transmission line EGME liquid limit Dielectric dispersion
Date of Defense	2007-03-27
Availability	unrestricted
Abstract Success in geotechnical analysis, design, and construction invariably requires that we have proper knowledge and understanding of (1) the strength, (2) the fluid flow properties, and (3) the stress-deformation behavior of the earth materials. These important engineering properties are primarily determined by the components and structure of a soil, which also dictate the soil’s responses in an electromagnetic field. As a nondestructive technique, the electromagnetic property measurement offers a promising approach to characterize earth materials and identify the effects of changes in environments. However, despite many investigations in the last several decades, the relationship between the frequency-dependent electromagnetic properties of soils and their components and structure are still not well understood. Hence, estimation of engineering properties of a soil in a quantitative way from electromagnetic measurements can be uncertain. In this research several tasks have been accomplished: (1) Development of a physically based model that provides a means of investigating the coupled effects of important polarization mechanisms on soil electromagnetic properties, and a means of relating the electromagnetic properties of a soil to its fines content, clay mineralogy, anisotropy, degree of flocculation and pore fluid chemistry; (2) Proposal of a practically applicable method to determine the volumetric water content, specific surface area and pore fluid salt concentration simultaneously from the dielectric spectrum; (3) Deduction of the wide-frequency electromagnetic properties of a soil by measuring its responses to a step pulse voltage using time domain reflectometry (TDR); (4) Establishment of the relationships between the specific surface area and compressibility, residual shear strength and hydraulic conductivity. This study establishes a framework for quantifying soil engineering properties from their electromagnetic properties. If properly determined and interpreted, the electromagnetic properties can also provide insights into the causes of soil property changes over time and can be very useful in studying the effects of biological factors in geotechnical engineering, a field that may offer great potential for future advances.
Files	Filename       Size       Approximate Download Time (Hours:Minutes:Seconds)     28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access    01Title_Abstract.pdf 59.59 Kb 00:00:16 00:00:08 00:00:07 00:00:03 < 00:00:01   02Acknowlegement_Synopsis.pdf 125.47 Kb 00:00:34 00:00:17 00:00:15 00:00:07 < 00:00:01   03Chapter1.pdf 67.21 Kb 00:00:18 00:00:09 00:00:08 00:00:04 < 00:00:01   04Chapter2.pdf 833.76 Kb 00:03:51 00:01:59 00:01:44 00:00:52 00:00:04   05Chapter3.pdf 1.15 Mb 00:05:19 00:02:44 00:02:23 00:01:11 00:00:06   06Chapter4.pdf 1.69 Mb 00:07:49 00:04:01 00:03:31 00:01:45 00:00:09   07Chapter5.pdf 392.81 Kb 00:01:49 00:00:56 00:00:49 00:00:24 00:00:02   08Chapter6.pdf 1.66 Mb 00:07:41 00:03:57 00:03:27 00:01:43 00:00:08   09Chapter7.pdf 1.34 Mb 00:06:12 00:03:11 00:02:47 00:01:23 00:00:07   10Chapter8.pdf 723.76 Kb 00:03:21 00:01:43 00:01:30 00:00:45 00:00:03   11Chapter9.pdf 75.22 Kb 00:00:20 00:00:10 00:00:09 00:00:04 < 00:00:01   12References.pdf 120.41 Kb 00:00:33 00:00:17 00:00:15 00:00:07 < 00:00:01   13Appendix.pdf 71.38 Kb 00:00:19 00:00:10 00:00:08 00:00:04 < 00:00:01

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