PURPOSE: To construct an underground stair while using an existing structure by performing nearly all operations on the outside of the structure by eliminating the need for great-scale timbering work during the excavating period by providing the ground to bear the existing structure prior to excavation.
CONSTITUTION: In constructing an underground stair under the ground on which an existing structure 1 is present, an underground continuous wall 2 is provided in the surrounding ground of the structure 1 and a tunnel 3 traversing the lower part of the structure 1 is also provided. Beams 5 are closely arranged horizontally from the inside of the tunnel 3 to the underground continuous wall and pressed into the ground to form a bearing ground 4. The subordinate ground is excavated to form the underground stair body 6 there at.
SHIOKAWA HIDEYO
GOTO TORU
TAKANASHI KAZUMITSU
KUNO YASUO
