COUNTERMEASURE CONSTRUCTION METHOD AGAINST LIQUEFACTION OF UNDER GROUND SUPPORTING EXISTING STRUCTURE

PROBLEM TO BE SOLVED: To provide an economical and rational countermeasure construction method against the liquefaction of under ground supporting an existing structure capable of forming a diaphragm wall having a substantially trapezoidal vertical section by designing an injection solidification method for the under ground supporting the existing structure (soft ground such as sandy ground). SOLUTION: The diaphragm wall 4 having a substantially trapezoidal vertical section the width of which is gradually reduced from a deep layer toward a shallow layer is formed in the under ground 3 supporting the existing structure 1 by repeatedly performing a process for drilling under ground 3 supporting the existing structure 1 at a fixed inclination angle by a boring machine type ground improving machine 2 installed at a position adjacent to the existing structure 1, and forming one or a plurality of ground improving bodies 4a in the axial direction of the drilled part while successively changing the axial angle. COPYRIGHT: (C)2009,JPO&INPIT