Velocity analysis in the GPR method for loose-zones detection in the river embankments

Determination of continuous distribution of the loose zones in the river embankment between points of geotechnical investigations is a very important matter for the embankment stability during the flooding. Presently, only non-invasive, geophysical methods can deliver such information. On the basis of numerous tests carried out by the Department of Geophysics at AGH University of Science and Technology in Cracow, the following conclusion may be drawn: zero-offset, reflection GPR profiling very seldom gives positive results at the detection of the loose-zones in the levee. Therefore, another concept of the loose-zones detection, using the GPR method, is presented in this paper. This technique is based on the modified CMP profiling, which allows to prepare a velocity map. Such a map may be used for evaluating of degree of the embankment disintegration.