| 摘要 |
<p>1,209,246. Tunnelling. ATLAS COPCO MCT AB. 21 March, 1968 [13 April, 1967], No. 13796/68. Heading E1F. When unstable earth conditions are encountered in a tunnelling operation by a tunnelling machine 1 having rotatable and radially adjustable cutting tools the machine is caused to excavate in sound rock preceding the unstable earth at a diameter larger than its previous boring diameter a tunnel length which will permit of the assembly of a sectional tunnelling shield 9 in front of the machine into which the machine can be driven and anchored before or after advance of the shield through the unstable earth depending whether this earth is to be removed by or without the aid of the tunnelling machine. On completion of the tunnel bore through the unstable earth the tunnelling machine is advanced out of the shield to continue the driving of the tunnel through sound rock.</p> |
