METHOD AND APPARATUS FOR CONSTRUCTING SPACE UNDER GROUND

PURPOSE:To construct a space under the ground, which is capable of all sorts of work by utilizing lesser portions of the ground's surface by a method in which a spherical outside peripheral wall is constructed connectedly to the lower part of a vertical pit constructed from the ground's surface, and the inside of the wall is excavated to form a space under the ground. CONSTITUTION:A cylindrical underground continuous wall 5 is constructed down to the bottom of an underground space A, and the inside of the wall 5 is excavated to form a vertical pit 1. An expanded diameter portion 1a is formed, and the bottom 4 is closed. Struts 6 are erected in the pit 1 and attached with a trencher 7 to excavate an arc-shaped trench 8. Spherical wall excavators 9 are set in the trenches 8 which are in turn closed with cement mortar 10. The spherical outside wall is excavated by the excavators 9, and concrete 10a is placed to construct the peripheral wall 2. An excavator 7 is also set in the pit 1, and the inside of the wall 2 is excavated to construct a space under the ground. The spherical space of good accuracy can thus be constructed.