| 摘要 |
PROBLEM TO BE SOLVED: To suppress the contamination diffusion of a ground resulting from foundation pile construction in a preboring method, while suppressing an increase of a construction period.SOLUTION: A foundation pile construction method includes: a step of drilling using an earth auger 7 for drilling the ground down to a supporting layer 109 while discharging drilling fluid, to form a vertical hole 113 and form a foot protection part 119 at the lower end of the vertical hole 113, the ground having a water stop layer 105 which exists in a position shallower than the supporting layer 109 in a predetermined vertical range and through which the vertical hole 113 vertically passes, a foot protection fluid filling step of filling foot protection fluid into the foot protection part 119 while pulling the earth auger 7 up, an auger pulling-up step of further pulling the earth auger 7 up and removing it from the vertical hole 113 while filling pile periphery fixing fluid into the vertical hole 113, and a pile building-in step of building a pile body 5 in the vertical hole 113 while filling the pile periphery fixing fluid into the vertical hole 113. In the steps, a fluid material upper face H in the vertical hole 113 is monitored and predetermined first-fourth control is executed to prevent the fluid material upper face H from lowering beyond a predetermined allowable lowering range. |
