FOUNDATION CONSTRUCTION METHOD OF UNDERGROUND STRUCTURE

To provide a foundation construction method of an underground structure to be constructed in low cost even when large vertical load is partially applied thereto.SOLUTION: A foundation construction method of an underground structure includes the steps of: constructing a pile 12 by driving an underground piled column 21 in the ground 2 at a center area 20A and constructing an outer earth-retaining wall 30 and an inner earth-retaining wall 31 on an outer peripheral area 20B; constructing a first floor skeleton 15A through support with the underground piled column 21 at the center area 20A and excavating the ground 2 while installing a timbering 32 on the outer peripheral area 20B; installing a steel column 22 by constructing a part of a mat foundation 13 on the outer peripheral area 20B and constructing the first floor skeleton 15 through support of the steel column 22; and constructing a remaining skeleton through excavating the ground 2 at the center area 20A as well as constructing the remaining skeleton while demolishing the inner earth-retaining wall 31 and the timbering 32 on the outer peripheral area 20B.SELECTED DRAWING: Figure 7 【課題】一部に大きな鉛直荷重が作用する場合であっても、低コストで構築できる、地下構造体の基礎の構築方法を提供すること。【解決手段】地下構造体の基礎の構築方法は、中央エリア２０Ａにて地盤２中に構真柱２１を打ち込んで杭１２を構築し、外周エリア２０Ｂにて外側山留め壁３０および内側山留め壁３１を構築するステップと、中央エリア２０Ａにて構真柱２１に支持させて１階床躯体１５Ａを構築し、外周エリア２０Ｂにて支保工３２を架設しながら地盤２を掘削するステップと、外周エリア２０Ｂにて、べた基礎１３の一部を構築して鉄骨柱２２の建方を行い、この鉄骨柱２２に支持させて１階床躯体１５Ｂを構築するステップと、中央エリア２０Ａにて、地盤２を掘削して残りの躯体を構築するとともに、外周エリア２０Ｂにて、内側山留め壁３１および支保工３２を解体しながら残りの躯体を構築するステップと、を備える。【選択図】図７