TUNNEL-BORING PENETRATION RATE AND MACHINE DESIGN

The experimental and theoretical findings of an ongoing research program on tunnel borability at the Colorado School of Mines are presented. A theoretical approach has been used to formulate predictor equations to calculate the forces involved in rock cutting with sharp and dull disc cutters. Concurrent with the theoretical analysis, extensive laboratory testing was undertaken with both sharp and artificially dulled disc cutters. These tests were carried out in three rock types and with full-size field cutters. Penetration, spacing, and edge angle, in that order, were found to affect cutting forces to a large extent whereas cutter diameter was found to be a variable of small significance. The effect of cutter wear on cutter forces was found to depend on the spacing of cuts and to decrease with increased spacing. It was concluded that wear is more detrimental to cutter performance at closer spacing of cuts. Predicted cutter forces were found to agree very well with those measured in laboratory cutting experiments. The theoretical behavior of dull cutter forces confirmed experimental observations in that the closer cuts were spaced the greater was the reduction in cutting efficiency of a disc cutter because of wear. Field boring data from a Jarva machine currently in operation in Chicago were procured and compared with predicted values, and agreement was very good. This represents an initial success in the application of the predictor equations to boring cases in the field. /Author/

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 21-28
  • Monograph Title: Tunneling and underground structures
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00196625
  • Record Type: Publication
  • ISBN: 0309028299
  • Files: TRIS, TRB
  • Created Date: Aug 28 1979 12:00AM