Surveying, modelling and visualisation of geological structures in the Tunbergettunnel

Abstract: The 3-d visualisation of a section of the Tunberget tunnel and important fracture zones was accomplished by combination of the topographic surface, measurements at the surface of fracture planes together with surfaces of dolerite dykes, results from magnetic modeling of dolerite dykes and tunnel mapping data. The topographic surface was represented as elevation contours with 1 m equidistance. The fracture and dolerite surfaces were measured geodetically in the field from a net of 20 total station locations. Each surface was measured at 3 points to determine its strike and dip. Totally 44 strike and dip estimates were obtained. The extent at depth of the dolerite dykes was also estimated based on magnetic measurements along 3 profiles. The location of the dykes was also known from geological tunnel mapping. ArcGIS and RockWorks have been used to process the data and to generate a 3-d visualization of the geometrical relation between targeted geological structures, the dolerite dykes and the tunnel. The area is of interest to be studied in more detail as the fracture zones and the parallel dolerite dykes connect the tunnel with a large wetland complex.