| 摘要 |
An element 22 for constructing an underground chamber comprises an elongate body with an abutment face 35 at an end thereof for abutting face 35 of a similar element, the abutment face 35 including means for resisting relative sliding movement of the two abutting faces; as shown, such means may be a rib 36a, 36b, and a groove 38a,38b, on each face. As shown, the faces may be bolted together; the elongate elements may have upper and lower walls 24,22 joined by side wall 28 and ribs 30, leaving a hollow portion for the receipt of mortar or backfill. Elongate ribs 44 may cooperate with complementary recesses 46 to facilitate stacking of the members. |
