| 摘要 |
<p>A tunnel lining tube is made up of a ring of segments which overlap, and which are bolted together by bolts passing through the overlap regions. Each segment is corrugated, so that the bolts pass through the tops and bottoms of the corrugations, clamping one inside the other, to form a tube with corrugations around it over its whole length. These corrugations are trapezoidal, the tops and bottoms being straight, and the ratio of the narrow top and the wide bottom portions is between 5 and 25. Preferably, the sides of the trapezoidal corrugations are also flat.</p> |
