VORTRIEBSEINRICHTUNG FUER DAS AUFFAHREN VON TUNNELN, STOLLEN U.DGL.

摘要

A tunnel drive shield is provided with a plurality of bracing units spaced around its periphery. The bracing units are expansible against the surrounding tunnel wall to control the direction of shield advance. A bracing unit is provided in each of the four shield quadrants defined by the vertical and horizontal center planes of the shield. Each of the bracing units is expansible in a non-radial direction.