EXCAVATION OF DEEP SHAFT BY SELF-STANDING RETAINING WALL

PURPOSE:To excavate a deep shaft by means of a self-standing retaining wall of solidified ground. CONSTITUTION:The ground is improved to form a solidified ground 4 in the range of a ring-shaped form (compression ring effect) up to the thickness showing the strength of a self-standing retaining wall in which the ground can the excavated regarding as the plane direction of the external peripheral ground in the excavating area, and in the range of the same depth with at least the excavated depth of the shaft from the ground level regarding as the vertical direction. After the solidified ground 4 has become rigid, the solidified ground is excavated by making use of the solidity to form a shaft 3. The peripheral ground of the excavating area is solidified to form a cylindrical or conical shape and the shaft 3 is excavated by an extremely deep level by use of the self-standing retaining walls. And hence, it can be carried out with less temporary construction and low cost and further, in a reduced period.