EXPERIENCE WITH VARIOUS SHIELD DRIVING MACHINES IN UNCONSOLIDATED ROCK. SECOND INTERNATIONAL TUNNELLING SYMPOSIUM, MUNICH, 12 APRIL 1989

The purpose of this paper is to provide a review of recent developments in shield driving machines and tunnel construction methods in areas where personnel have access. The use of such machines is illustrated by a small number of selected construction projects. Brief details are provided of the following methods: bentonite shield; hydroshield; thix shield; mix shield; membrane shield and earth pressure shield. New developments to remove stones during excavation are described briefly. Bentonite shields are being equipped with lockable cutting wheels which have roller bits in addition to the stripping tools and blades. These will crush the larger stone blocks at the heading and then convey them to the shield chamber. The blocks are then conveyed away hydraulically or fed through a crusher to make them even smaller. Earth pressure shields are having similar adaptations made to them in order to remove stones. However the problem of changing tools has still to be solved. A new version of the thix shield (the uni shield) in which the cutter is replaced by an excavator is currently being tested. This excavator is capable of loosening stones, and then conveying them via a crusher or a sluice. Large erratic blocks can be blasted after an appropriate tool change. Changing tools or repairing the excavator is relatively simple in comparison to a machine fitted with a cutting wheel. The German title of this paper is as follows: "erfahrungen mit unterschiedlichen schildmaschinen im lockergestein". For the covering abstract of the conference see IRRD 824157.

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  • Accession Number: 00497991
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Sep 30 1990 12:00AM