Several of the conclusions presented by the authors are discussed and amplified. It was noted that the main source of settlement for the first tunnel was about the shield, and comments are made regarding the use of settlement measurements to detect the source of lost ground. The loss of ground about the second tunnel is discussed and it is pointed out that the major improvement in the construction procedure for the second tunnel was the use of a shorter shield that in comparison to the first shield, could be steered with a great deal less plowing and pitch change. Surface and deep movements are compared and it is observed that although the volumes of surface settlement were similar for the first and second tunnels, the settlements for driving the second tunnel was spread over a large area encompassing both tunnels. Consequently, the maximum settlement was half that for the first tunnel and occurred between the two tunnels.

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Filing Info

  • Accession Number: 00134653
  • Record Type: Publication
  • Report/Paper Numbers: ASCE #11074
  • Files: TRIS
  • Created Date: Jun 23 1976 12:00AM