A NEW SENSING SYSTEM FOR PRE-EXCAVATION SUBSURFACE INVESTIGATION FOR TUNNELS IN ROCK MASSES. VOLUME I. FEASIBILITY STUDY AND SYSTEM DESIGN

This report includes a feasibility study and system design for an initial prototype of a sensing system for pre-excavation subsurface investigation for tunnels in rock. Tunnels in rock are very expensive, and costs often rise far above estimates when unforeseen problems are encountered during excavation. New techniques in rapid excavation technology, such as the development of boring machines, have increased the need for improved site investigation. Possibilities for a new sensing system that will provide more complete data on subsurface conditions were investigated. Favorable results obtained from high-resolution geophysical sensing in boreholes have been combined with improvements in drilling of long, horizontal, precise boreholes in order to provide an economical alternative to pilot tunnel for subsurface investigation. Pilot tunnel costs as with all subsurface construction are rising at rates much higher than the economy, thus the use of borehole site investigation has potentially very high benefit/cost characteristics. The prototype system designed is a highly mobile geophysical measurement (data acquisition) system. The system will take electromagnetic radar measurements, pulsed acoustical measurements, and multi-spaced array resistivity measurements. The sensors will be used in traverses along the borehole, and data will be taken and stored on magnetic tape for subsequent reduction and analysis at a computational center. The system could reduce accidents, reduce bid contingencies, and reduce other factors contributing to rapid escalating costs of subsurface excavation. Volume I describes the feasibility study and system design. Volume II contains the Appendices A-R.

• Supplemental Notes:
  • See also Vol. 2, PB-276 721.
• Corporate Authors:

  ENSCO, Incorporated

  5400 Port Royal Road
  Springfield, VA  United States  22151

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Rubin, L A
  • Fowler, J C
  • Griffin, J N
  • Still, W L
• Publication Date: 1976-8

Media Info

• Pagination: 206 p.

Subject/Index Terms

• TRT Terms: Acoustic detectors; Acoustic emission; Analysis; Boreholes; Construction; Costs; Data collection; Excavation and tunneling; Functional analysis; Geological events; Geological surveying; Radar; Rocks; Seismic prospecting; Seismicity; Surveys; Tunneling
• Uncontrolled Terms: Construction costs; Cost analysis
• Old TRIS Terms: Geological conditions; Rock tunneling; Seismic surveys
• Subject Areas: Bridges and other structures; Construction; Finance; Geotechnology;

Filing Info

• Accession Number: 00174740
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: FHWA-RD-77- 10 Final Rpt., 1061-TR-3-1-Vol-1
• Contract Numbers: DOT-FH-11-8602
• Files: NTIS, TRIS, USDOT
• Created Date: Apr 12 1978 12:00AM