Tunnel Boring Machine Performance and Ground Properties: Report on the Initial 1 1/2 km of the North Wear Drive, Kielder Aqueduct

摘要

The report describes a study of the construction of the North Wear tunnel from 124 to 1600 m chainage using a tunnel boring machine and the geology encountered. Performance of the tunneling system was assessed from shift inspectors' reports and recorders on the tunnel boring machine. Overall non-driving time accounted for 78 percent of normal working hours, although this reduced to 71 percent when the zone with anomalous behavior was excluded. Examination of how working time was used in the tunnel showed a fairly constant cutting performance whatever the rock type but with large variations in overall progress and also the extent to which progress had been hampered by the difficulties of coping with fractured ground. Principal among these was the blocking of the spoil chute, primary underslung chain conveyor and the late supporting of the roof. The work suggests that improvement can best be made by reducing the time when the tunnel boring machine is idle. (Copyright (c) Crown Copyright 1979.)