The Application of the Ground Penetrating Radar (GPR) as a Non Intrusive Method to Measure Soil Water Content

This paper assesses the use of the ground penetrating radar, GPR, for measurement of soil water content. Results of laboratory Constant Mid Point tests, performed on an apparatus developed for this purpose, were analysed, on the basis of Time Domain Reflectometry theory. All tests were performed on sand. Electromagnetic pulses velocities were measured in a dry sample (w ~ 2%) and a saturated sample (w ~ 24%) under steady-state conditions and in unsaturated samples under transient conditions. Based on laboratory results, a theoretical equation is proposed in order to forecast electromagnetic pulse velocity in unsaturated mediums, showing a good agreement with experimental results.