CAISSON IMMERSION METHOD

PROBLEM TO BE SOLVED: To provide a caisson immersion method capable of immersing a caisson while lowering man-hours and construction costs.SOLUTION: The caisson immersion method for installing a caisson 1 comprising a blade edge 6 by sinking it from a ground surface GL side of a ground to a predetermined depth Dc, which comprises: forming a shaft wall body 20 extending in a vertical direction in a vicinal region of a ground downwards of the blade edge and measuring at least depth-directional strength distribution of the ground in the vicinal region; determining at least per predetermined depth whether there is an unsuitable region for sinking G1a, whose strength exceeds a predetermined strength range, in the ground downwards of the blade edge based on a measurement result of the strength distribution; when the unsuitable region for sinking G1a is present, disposing ground strength adjusting means 30 in a space within the shaft wall body 20; and installing the caisson 1 by sinking it to the predetermined depth Dc as strength of the unsuitable region for sinking G1a is adjusted so that it is within the predetermined strength range by the ground strength adjusting means 30.SELECTED DRAWING: Figure 3 【課題】工数及び工費を抑制してケーソンを沈設可能なケーソン沈設方法を提供する。【解決手段】刃先部６を備えるケーソン１を地盤の地表面ＧＬ側から所定の深さＤｃまで沈下させて設置するケーソン沈設方法であって、刃先部下方地盤の近傍領域にて、鉛直方向に伸びる立坑壁体２０を形成すると共に、近傍領域の地盤の少なくとも深さ方向の強度分布を測定し、強度分布の測定結果に基づいて、刃先部下方地盤に、強度が所定の強度範囲を超える沈下不適合領域Ｇ１ａがあるか否かを少なくとも所定の深度毎に判定し、沈下不適合領域Ｇ１ａがある場合は、立坑壁体２０内の空間に地盤強度調整手段３０を配置し、この地盤強度調整手段３０により、沈下不適合領域Ｇ１ａの強度を所定の強度範囲内に収まるように調整した状態で、ケーソン１を所定の深さＤｃまで沈下させて設置する。【選択図】図３