CONSTRUCTION METHOD OF SOIL CEMENT CONTINUOUS WALL

To provide a construction method which can handle deeper boring length as a construction method of soil cement continuous wall with which original ground is drilled with a biaxial coaxial single axis casing auger machine, preceding piles are constructed by prior excavation at intervals, and trailing piles, which are columnar bodies of soil cement in between, are constructed by trailing excavation so that the columnar bodies of this prior excavation overlap each other to make a soil cement columnar wall body.SOLUTION: As leading excavation, with a biaxial coaxial earth auger 21 that uses a casing + screw with a diameter (φ600-680 mm), which is more rigid than a single shaft screw, excavation is progressed to the depth of the gravel/boulder layer and bedrock layer where excavation accuracy tends to decrease, and as preceding excavation, using a large-diameter (850-1100 mm) screw equipped with a two-stage excavation head after the leading excavation 22, the hole that has been accurately loosened during leading excavation is expanded, and as trailing excavation, a multi-axis auger excavator is used to construct trailing piles, which form a columnar wall of soil cement, so that the columnar bodies from the preceding excavation overlap each other.SELECTED DRAWING: Figure 1 【課題】二軸同軸式単軸ケーシングオーガ機で原地盤を削孔し、先行杭を間隔を存して先行掘削で造り、この先行掘削による柱状体相互に重なるように間にソイルセメントの柱状体である後行杭を後行掘削で造り、ソイルセメントの柱状壁体とするソイルセメント連続壁の施工法において、より深い掘削長に対応できる施工法を提供する。【解決手段】先導掘削として、単軸スクリューより剛性が高い、口径（φ600〜680mm）のケーシング＋スクリューを使用した二軸同軸式アースオーガ２１にて、掘削精度が低下しやすい礫・玉石層や岩盤層の変わり目以深まで掘り進み、先行掘削として先導掘削２２の後に二段掘削ヘッドを装着した、大口径（850〜1100mm）のスクリューを使用して先導削孔で精度良く緩められた穴を広げて行き、後行掘削として多軸オーガ掘削機で先行掘削による柱状体相互に重なるように間にソイルセメントの柱状壁体である後行杭を造る。【選択図】図１