ABSTRACT
The second metro line in Warsaw is under construction. The east and west extensions are currently being constructed. Twin tube metro tunnel was driven with EPB TBM in very complex geotechnical conditions - Quaternary soils (Sandy Clays, Fine Sands, Clays) and Pliocene clays. The tunnel external diameter is 6.5 m; the overburden varies from 5 m to 8 m; the distance between tunnel axes is 14 m. Because of dense urban area, extensive monitoring system of ground surface settlements, the expansion of subsiding trough and displacements of subsoil over the TBMs tunnels were implemented. In the paper, the results of settlements monitoring at the length of 502 m in 8 cross-sections, during the passage of two EPB TBMs are presented. In the paper, finite element prediction of subside trough is discussed and compared with real data obtained from monitoring.
