CONSTRUCTION OF UNDERGROUND SPACE

PURPOSE:To reduce the working area for an underground space by providing a specified vertical shaft in a portion divided with two or more rows of opposite continuous walls in the ground, pressing-in support members constructing upper slabs of an underground space in the direction of the continuous walls, connecting respective upper portions to each other, and excavating the inner underground space. CONSTITUTION:Two rows of parallel continuous walls 1a, 1b are installed in the ground to rebury the upper side of a space to be made as an underground space, and a vertical shaft 7 is provided in the portion enclosed with the walls 1a, 1b. A pre-supporting member 3 is pressed-in from the vertical shaft 7 toward upper slabs parallel to the walls 1a, 1b and horizontally, and a working space 12 is excavated underside of the member 3. As the progress of the excavation, both end portions of a beam 4 installed below the member 3 are connected to the walls 1a, 1b respectively to support the member 3 from underside, and the excavation and the installation of beams 4 are repeated similarly to the tip of the member 3, to extend the underground space 8 along the walls 1a, 1b, and to construct upper slabs. And bottom slabs 6 are installed to construct the underground space 8 of large cross section.