SOIL IMPROVING STRUCTURE AND SOIL IMPROVING METHOD CAPABLE OF CONTROLLING PERIPHERAL GROUND DISPLACEMENT

PROBLEM TO BE SOLVED: To suppress and control horizontal displacement and ground settlement occurring in the ground on the periphery of an area targeted for improvement. SOLUTION: A plurality of drain materials 16 are almost vertically driven into the area 13 targeted for improvement with their head portions extended above the ground surface, and a vacuum pump 15 is connected to the head portions of the respective the drain materials via a horizontal drain material 12. Then, the drain materials and the horizontal drain material are hermetically coated with a sheet material 11, and a wall body or a groove is constructed along the drain materials in the ground on the periphery of the area targeted for improvement. Further, tiltemeters 18 for measuring horizontal displacement are set at the wall body or the groove, and the peripheral ground. While the horizontal displacement at stations are measured, the vacuum pump is driven to introduce and drain water from the drain materials via the horizontal drain material to the vacuum pump, and loading fill 14 is piled up on the sheet material, depending on fluctuations of the deformation, to thereby control the horizontal deformation.