Seismic Characterization of Tunnel Boring Machine Activity near Boston, MA, USA

LA-UR-99-5027
R. J. Greaves1, P. M. Roberts2, C. G. Doll3, L. K. Steck3, M. C. Fehler2,
N. M. Toksoz3, R. J. Turpening3, H. J. Hooper3, M. S. Edie3, and D. F. Baker2

1MIT Lincoln Laboratory, 2Los Alamos Seismic Research Center, 3MIT Earth Resources Laboratory


Introduction

To characterize the seismic wave field associated with hard rock tunneling and associated activities, 14 seismic stations were deployed in and near a tunnel being bored by a tunnel boring machine (TBM) for a water project near Boston. The 5.15 m tunnel is being bored through granitic and metamorphic rocks at a depth of about 125 m. Seismographs were deployed for about 1 week during August of 1999, and recorded about 40 hours of TBM activity. The deployment consisted of both short-period and broadband instruments, and an array of aperture 60 m was deployed at the second-closest broadband site. During one 8-hour work shift, a short-period and broadband sensor pair were deployed inside the tunnel, about 35 m behind the TBM.

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Map & Cross-section of Tunnel
Courtesy of GeoEnvironmental, Inc. & Metrowest, 1995
Tunnel Boring Machine Map of Deployment


Introduction | Spectrograms | Signal and Noise Spectra | TBM Signal Attentuation
Frequency-Wavenumber Analysis of the Mini-Array | Acoustic Resonances | Conclusions