| 摘要 |
PROBLEM TO BE SOLVED: To reliably prevent groundwater in a lower permeable layer from being contaminated by a pollutant contained in an upper permeable layer during and after construction of a foundation pile in a foundation pile construction method to construct the same by preboring method.SOLUTION: A foundation pile construction method, to install a precast pile 5 in the ground having a first layer 103, a water stop layer 105 below the first layer and a second layer 111 further below the water stop layer by preboring method, comprises: a replacement process to excavate a vertical hole 113 to the water stop layer with bentonite compounding fluid 9 as drilling liquid and to replace soil in an excavated region with the excavation liquid; an enlarged diameter water stop section construction process to construct an enlarged excavation section 115 in the water stop layer so that at least either an upper edge or a lower edge thereof is positioned in the water stop layer and a diameter thereof is enlarged and to construct an enlarged diameter water stop section 117 with cement milk; a foot protection section construction process to construct a foot protection section 119 at the lower edge of the vertical hole in the second later; and an installation process to install the precast pile. |
