Gardien W.

In densely populated areas of the Netherlands, several bored tunnels have been built in the recent past and are to be built in the near future. At other bored tunnels, it has been found that the Tunnel Boring Machine (TBM) often generates more vibrations than passing trains during the exploitation phase. The COB (Netherlands Centre for Underground Construction) committee F511 has set up a research program for the vibrations during the construction of the “Green Heart Tunnel”. The “Green Heart Tunnel” is part of the high speed train link from Amsterdam to the Belgium border. The goal of the committee was to develop a protocol to predict vibrations at densely populated areas. Based on the knowledge that the source of the vibrations can differ from TBM tot TBM and is often unknown, a protocol has been developed in which the vibration characteristics of the TBM are measured at a location without nearby buildings. After that a prediction can be made for a residential area with a different soil profile. The measurements were carried out at 4 locations. At the first measurements it was found that 2 types of vibrations could be distinguished: continues vibrations during the boring and stochastic vibrations during the placement of the tunnel segments. The following approaches were used for the predictions of the 2 types of vibrations at the location with nearby buildings: empirical, spectral elements, 2D FEM and 3D FEM. The predictions and measurements have been evaluated. Generally, the predictions of the spectral elements and 2D FEM models were the most accurate. Furthermore, it turned out that a simple measurement with a few measurement points would be sufficient for a prediction. An adapted prediction protocol based on simple measurements and 2D predictions has been proposed.