Application of GPR Scanning for Landslide Investigations in Polish Carpathians

Landslides in recent years became a serious problem and were causing economic losses in Poland. They are formed on steep Carpathian slopes of flysch sediments. Built from many thin layers of marine sedimentation, soil-rock type deposits were difficult for in-situ and laboratory tests. It required effective techniques of investigations. Traditional drillings were very important but time consuming, costly and not always gave answer for the entire question in mass movement investigations. Some types of geotechnical tests were proper for soils some other only for rocks. Therefore good quality core drillings always should be connected with other types of field measurements and monitoring techniques chosen with respect for the landslide type and its internal structure. Ground penetration radar GPR measurements were found to be a one of very useful methods in conjunction with other geotechnical engineering tests. Using GPR surveys landslide depths were recognized at 1-20m below the natural terrain level. Over 10 km of GPR measurements was performed on 24 landslides inside the project for Polish Roads Authorities, financed by European Investment Bank. In the paper conclusion from using GPR, together with diamond impregnated core drillings, ground movement measurements, groundwater monitoring and geotechnical laboratory tests are described.