| 摘要 |
<p>The tunnelling unit is successively pressed forward, and earth is successively removed from inside it, leaving the layer above it in position. The unit is used for building prefab. tunnel units (1) with sloped side flanks in non-cohesive terrain (2), esp. below roads or railways. In the area of the unit roof pressing surface, earth is injected with material to make it cohesive, so that a loadbearingly cohesive, but removable, layer (3) is formed in the ground. Injection pref. takes place in stages, before each pressing thrust. Cohesive walls may be formed, perpendicular to the layer, by injection.</p> |
