| 摘要 |
PROBLEM TO BE SOLVED: To produce a concentrically cylindrical improved body by infiltration grouting and a large improved body having a diameter of about 5 meters. SOLUTION: The ground for construction work is digged down to a predetermined depth to form an insertion hole 31, a grouting external pipe having a plurality of packers 6, 6 at an interval in the axial direction in an outer face part and grouting ports 7 between adjacent packers 6 and 6 is relatively inserted into the insertion hole 31, and both adjacent packers 6, 6 are inflated and adhere closely to a wall face of the insertion hole 31. While a region surrounded by adjacent packers 6, 6, the wall face of the insertion hole 31, and an outer face of the grouting external pipe is used as a space, and while the space is filled with chemical liquid through the grouting port 7, chemical liquid is grouted into sand or sand and gravel ground at a grouting speed of above 10 liters/min and below 40 liters/min. |
