Site Investigation of Twin Tunnels by Joint Application of Seismic and Engineering Geophysical Soundings (CPTe)

The near-surface geophysical data have become key components in the development of the engineering of major underground structures. Geological and Geophysical Institute of Hungary (GGI of Hungary) carried out a detailed geophysical survey along the twin tunnels of a new Metro line in Budapest, Hungary. Following the tunnel boring activity several sinkholes were detected at the surface along the path of the twin tunnels. GGI of Hungary carried out engineering geophysical soundings (CPTe) and non-invasive seismic technologies (3D seismic tomography) in order to mitigate the potential risk of any material damages in the future. The aim was to get to know the physical parameters of the soil layers. The joint application of the two methods was able to detect the known and the hidden potential sinkholes using state-of-the-art technology.