Tunnel or mine gallery tubbing ring blocks - have faces angled so that any one can be ridge closing block

摘要

The two annular boundary surfaces lie in planes at an acute angle, in a ring for tubbing, made up from blocks with abutting flat boundary surfaces forming joints running across the annular surfaces. The system is used in tunnels or underground gallery construction. Planes corresponding to the flat dividing joints on both sides (2) form acute angles in the line towards the central axis (T) of the tubbing and also in the lengthways direction of the tubbing sheath. The two planes intersect in straight lines (5,6). The lines of all the dividing joint planes are located on the sheathing surfaces of cones (7,8). Every other tubbing block can be a closing block, and the ring can be turned about any angle, with ridge block as closing block, so that the ring can be built up from the bottom upwards.