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I. Kreutzer, A. Radinger, E. Brückl, W. Chwatal, D. Kostial:
"TSWD - State of the art and current developments";
Talk: Sageep 2014, Boston; 2014-03-16 - 2014-03-20; in: "Proceedings Sageep 2014", (2014), ISSN: 1554-8015; Paper ID 17, 4 pages.

The Tunnel Seismic While Drilling (TSWD) method has been developed to predict the geological situation ahead of the tunnel face without disturbing the construction progress in the case a Tunnel Boring Machine (TBM) is operating. The vibrations of the TBM are used as the seismic source and processing of the seismic data is targeted to the detection of reflections from fault zones ahead of the tunnel face. Modern TBM`s achieve advance rates up to 50 m per day. Near real time processing and at least daily prediction is essential. These circumstances put high demands on instrumentation, data transmission, processing, and logistics. The principles of the methodology and the state of the art will be presented. Until now we applied TSWD at four tunnel construction sites in Austria. Optimized adaptation of the TSWD technique to the particular TBM type represents a further challenge. It will be shown how instrumentation and processing have to be adapted individually for each tunnel. The final interpretation of the seismic data contains a prognosis about 100 m ahead of the TBM including location, thickness, and geometry of construction relevant geological features. A close collaboration with geologists on site supports an adequate interpretation. Current developments which aim further improvements will be addressed. The comparison of the TSWD results with the encountered geology shows that wider fault zones over a thickness of 10 m can be successfully resolved, smaller fault zones are partly detected. General, there is a prediction accuracy of about 5 m for the beginning of the structures. It was possible to detect 80% of the prominent faults or transition zones at all tunnel sites. On the strength of past experiences faults with a high risk impact on the tunnel construction can be clearly defined.

Tunneling, seismic source

http://publik.tuwien.ac.at/files/PubDat_230929.pdf

Project Head Harald Schuh:
VPM - Kooperation