| 摘要 |
<p>The tunnelling shield (10) has a base segment (12) and two expanding segments (13, 14) which are connected in an articulated manner on either side of the base segment (12), secure the excavation space in the face and roof area and have overlapping segment extensions (13b, 14b) which are pressed against the excavation wall by expanding devices (16) with expanding cylinders (17). The tunnelling machine is displaceably mounted in a bearing segment (19) firmly connected to the base segment (12) and having guide rails (20). Firm bracing of the expanding segments (13, 14) inside the excavation space is obtained by extension of the expanding cylinders (17), whereas the bracing is released by retraction of the expanding cylinders (17) so that the advance of the shield (10) is facilitated and the controllability of the shield (10) is improved. <IMAGE></p> |
