The geophysical investigation of drilling obstacles for microtunneling projects by means of GPR

Up to now the experience gained shows that the GPR measuring process is best suited to be used for geophysical pre-study of microtunnelling routes. Such pre-studying of drilling routes often means that the GPR-technology has to be used to the limits ofits performance capacity. Inspite ofthe high values of signal absorption in loamy soils as well as loss due to scattering in inhomogeneous piling, the task is to detect utilities as far as possible without exception and to localize precisely changes in soil structures underground. Considering the relatively high degree of lateral and vertical variation of GPR-sections in the direct surroundings of urbane infrastructures, the GPR-geophysicist is faced with a demanding task, whereby the experience gained under similar circumstances play an important role. Diverse detection tasks are shown, representative for the area of Southern Germany and Austria. Ranging from the detection of pipes in 4-channel antennae configurations, to the location of geological layers and drilling obstacles, it demonstrates a spectrum of typical cases and a survey of the application possibilities of the GPR-technology for pre-studying of drilling routes in Southern Germany and Austria.