The Effects of Ground Vibration During Bentonite Shield Tunnelling at Warrington

摘要

The research was carried out during the bentonite shield tunnel drive for the Acton Grange trunk outfall sewer at Warrington, Cheshire. This tunnel was driven through cohesionless Drift deposits beneath a built-up urban environment, with a cover of less than 6 m. The environmental effects of the ground vibration caused by the excavation process were investigated with particular regard to ground settlement by compaction. Vibration data were recorded from transducers located in boreholes, on the surface, on the tunnelling machine and on the concrete tunnel lining. These records were processed to characterise the vibrations in terms of peak particle velocities, frequency spectra and spatial attenuation. Vibration from the excavation process probably caused ground compaction which contributed significantly to ground settlement and its effects. The vibration was not likely to have caused any direct damage by dynamic stressing but the associated low level noise did cause concern among local residents.