ANALYSIS OF CHANGES IN SOIL VOLUMETRIC WATER CONTENT USING COMMON-OFFSET GPR

Abstract

In highway engineering, GPR is a nondestructive tool for prediction pavement layers conditions, the quality of subgrade soils, and assessing other pavement conditions, such as moisture-related pavement damage. From the reflected GPR wave information, dielectric properties of the materials, which are highly dependent on soil or aggregate-water-air systems, can be estimated. An increase in dielectric constant may indicate an increase in moisture content of dielectric materials. However, the relationship between dielectric value and moisture content is complex and controlled by many factors. GPR studies, which consider both real and imaginary parts of dielectric value and its frequency dependent behavior, have shown potentials for developing more robust model to predict moisture content. This paper presents an overview of ground coupled GPR capabilities in estimating water content that is necessary in assessing pavement condition. Two types of antennas (800 and 500 MHz) were employed to decide the best monitoring for the water seepage under new or existing pavements. As well as, the data outcomes will be presented with the necessary data filtration and post processing softwares to observe spectrums behavior during the wetting cycles. Finally, it is concluded that estimation of soil water content using Common-Offset GPR measurements mode facilitates rapid data acquisition.