Simple method for estimation of water content of roadbeds using multi-offset GPR

roadbeds using multi-channel GPR is described. GPR is a continuous and non-destructive method and its capabilities of providing information on soil and water content is well documented in the past. Most of these earlier described methods involve several time consuming measurements with a variety of antenna settings. A multi-channel radar system can however make more efficient measurements through the use of independently controlled transmitters and receivers in the antenna array. The results, from measurements with a 500 MHz GPR system, show a clear correlation between the GPR data and the soil water content in a Swedish roadbed. Further evaluation is, however, needed to compare different antenna frequencies and to calibrate the equipment together with reference velocity analysis.