In this discussion, the mechanics and performance of a tunnel boring machine (TBM) are discussed. Determining the tensile or shear behavior of rocks is seen as important in defining their fracture and cutting characteristics. Because it is difficult to prepare and test rock specimens in the pure tensile or shear mode, other tests have been developed. In addition to unconfined compression, other testing modes are used to evaluate rocks. These techniques are designed to determine indirectly, the strength in: compression; tension and shear; or, flow and impact. In order to assess the cutability of rock types of a tunnel route, laboratory cutting tests may be necessary in order to determine the performance indicators of a given machine design in those rock types. Laboratory rock cutting and drilling experiments simulate the field cutting conditions at reduced scale. The parameters considered in laboratory experiments and discussed in this paper are the normal force, type, size, speed, spacing and bluntness of the cutters. The laboratory experiments are useful when correcting and analyzing large sets of data. Once a performance indicator has been established it can be selected as a means of monitoring the performance of a TBM in the field. The discussion concludes by reemphasizing the importance of optimizing the operation of the cutters of TBM by the use of performance indicators failure to do so can lead to an increase in cutter consumption costs.

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Filing Info

  • Accession Number: 00157164
  • Record Type: Publication
  • Report/Paper Numbers: ASCE 11589
  • Files: TRIS
  • Created Date: Nov 9 1977 12:00AM