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|Title:||Seismic analysis of tunnel boring machine signals at Kerckhoff Tunnel|
|Authors:||Pennsylvania State University.|
Greenfield, Roy J.
|Publisher:||Geotechnical Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||Miscellaneous paper (U.S. Army Engineer Waterways Experiment Station) ; GL-83-19.|
Abstract: In conjunction with OCE project AT40-C0-007, "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 for 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 8000 ft and the tunnel boring machine could be accurately located within approximately 100 ft at a slant range of approximately 5000 ft. Certain characteristics of an operating TBM were evident within the seismic signature. These were start-up, shutdown, placement of gripper pads, and boring operations. It was concluded that TBM signal amplitudes were approximately 100 times the amplitude of natural noise on the surface above the operation and would likely be observable to distances of about 10,000 ft or more at sites similar in geology to the Fresno site. In view of the successful evaluation of the MSHA system, recommendations were made for tailoring the equipment and its deployment for special application to military needs.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Miscellaneous Paper|