GROUND IMPROVING METHOD APPLYING TOP-DOWN CONSTRUCTION METHOD

摘要

PROBLEM TO BE SOLVED: To improve the ground just below an underground building frame into a lattice-shaped wall form mainly by sequentially repeating cutting of the ground and construction of underground building frame while constructing a main building frame to the direction of underground, and directly improving the ground just below by means of a small ground improving machine carried at a final floor finishing level, thereby constructing the final floor. SOLUTION: Cutting of the ground and construction of underground building frame constructed of beams 10 and a floor 1 are repeated sequentially downward to proceed the construction of underground part 2 of a building by the top-down construction method. The area from a lowermost floor finishing level L3 to a planned floor finishing level downward therefrom are excavated by a small backhoe or the like carried thereat, and the bottom surface of lowermost floor is 11 taken as a construction floor surface 4. For example, a one-shaft type small ground improving mechine 3 is carried onto the surface 4 from the ground. Then, the ground to be improved 5 just below the surface 4 is excavated to a specified depth D by the machine 3. Thereafter, a ground stabilizing material 7 such as cement slurry or the like is poured therein which is stirred and mixed with the excavated earth to thereby improve the ground to be improved 5.