WORKING FACE INDEPENDENCE METHOD IN COLLAPSE BEDROCK TUNNEL

摘要

PURPOSE: To maintain the independence of a working face by laying out a plurality of construction positions on the working face surface in the case collapse preventing soil mortar piles are constructed, constructing a specific number of piles, and making uneven the depth of the piles. ;CONSTITUTION: Boring is made by a two throw drill, and when the drill is pulled out, a solidification material such as soil mortar, is injected from the front end, and it is stirred and mixed with slime to form horizontal piles. At that time, a plurality (for example, 3) of construction positions A, B and C are laid out to a working face surface, and approximate 1/3 of the total number of the horizontal piles per one face are constructed. In the case the face is excavated, the depth of the remaining horizontal piles is different at every A, B and C. The number of layouts is four to five in accordance with the length of a shorting on the length of the horizontal pile. According to the constitution, excavation is made while maintaining the independence of the face easy to collapse.;COPYRIGHT: (C)1995,JPO