http://worldcat.org/entity/work/id/3043507

Seismic analysis of tunnel boring machine signals at Kerckhoff Tunnel

In conjunction with OCE project AT40-CO-007, 'Tunnel Detection in Rock', a field evaluation of Mine Safety and Health Administration (MSHA) seismic detection system was performed at a site near Fresno, Calif. The MSHA system was originally designed for deployment after a mine disaster so that trapped miners could be located using seismic signals which they would generate by pounding on the ceiling or floor. The concept of this system was thought to be directly applicable to military needs in locating clandestine tunneling activity. The objective of this evaluation was to determine the ability of the MSHA system to detect a large tunnel boring machine (TBM) operating in granite at depths in excess of 1300 ft, the degree of accuracy of the system in locating the TBM, and the maximum range fore reliable detection and location. Early reconnaissance revealed that the natural site noise was approximately 4 ips. Signals received above that level could be processed with a high degree of confidence. During the series of tests, it was determined that the TBM could be detected at a horizontal range of about 80000 ft and the tunnel boring machine could be accurately located within approximately 100 ft at a slant range of approximately 5000 ft.

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