EXCAVATION AND METHOD OF EXCAVATION

摘要

The excavation and method of excavation of the present invention reduces the risk and the amount of structural support necessary in undercut-and-fill excavations while increasing the strength of such excavation. A decline is excavated and a first series of spaced tunnels is driven in a first direction at a first level. The first series of tunnels is then provided with a substantial layer of high strength material such as concrete, to form a first series of monolithic reinforcement beams, the space above being then backfilled to the roof with support material. A second series of tunnels is then driven between the filled first series of tunnels. The second series of tunnels is then provided with a like layer of concrete to form reinforcement beams contiguous with the first series of beams, and then backfilled with support material. A third series of spaced tunnels is then driven in a second direction at a second level of the decline, the second direction being transverse to the first direction. The tunnels of the third series are then reinforced and filled and a fourth series of tunnels is then driven between the tunnels of the third series, reinforced and subsequently filled. This is repeated at lower levels, in each case the direction of the tunnels being transverse to the direction of the tunnels of the level immediately above. A cross-wise lattice of supporting beams is thus created by the reinforcement beam operations. This lattice protects the tunnels beneath it so as to allow wide excavations with minimal structural bracing and controls the amount of unprotected opening at each stage of the operation.