TBMs are widely utilized for infrastructure projects and to reach favorable excavation rates, selected TBMs should be operated to comply with the geological changes. Therefore, recognizing and understanding the geological changes during the excavation is of great importance. In that aspect, vibrations generated during the excavation can give useful information about the geological conditions. However, this topic has not been studied in detail and only limited number of researches have been conducted up to now.

This paper summarizes vibration patterns created during rock cutting by using a full scale linear rock cutting machine as well as during TBM excavation in field. Vibrations created during TBM excavation and TBM performance data recorded for 328 rings, were compared to each other and geological data. It was seen that geological conditions effects vibration pattern. In addition it was also found that broken or fat cutters have also effect on vibration. It was also seen during the laboratory tests that acceleration amplitudes were related with rock type and cutting patterns.

1 Introduction

Performance of a Tunnel Boring Machine is directly related to its specifications, geological conditions and as well as their crews' abilities to interpret these conditions and react properly, especially operators. Excavation operation generates vibration due to rock cutting process, which then is transmitted to the cutterhead and other parts of the TBM. These vibrations could help to understand geological conditions in front of the TBM without face inspections, which could save lots of time.

There are several researches made to understand forces and vibrations created during rock cutting. One of the first researches was made by Samuel and Seow (1984). Strain gauges installed to the discs' shafts of a 4.1 m diameter Robbins 146-193 model TBM and force components acting on a disc cutter was investigated. Then, frequency analyses done on force data. Another detailed research on this area was performed by Gertsch (1991, 1993) and frequency analyses was performed on the forces caused by 17" constant cross section (CCS) disc cutter during the experiments with a linear cutting machine (LCM). These researches were performed using strain-gauges instead of accelerometers to understand vibrations, which is different from the studies performed later on this area.

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