LIQUEFACTION PREVENTION AND MAINTENANCE METHOD FOR EXISTING BANKING

PROBLEM TO BE SOLVED: To provide a liquefaction prevention and maintenance method for an existing banking with reinforced integrity of non-liquefaction integral structure that suppresses deformation on an outer periphery of an existing banking on a foundation ground, even when the foundation ground is liquefied at a time of earthquake.SOLUTION: A liquefaction prevention and maintenance method for an existing banking 110 includes: a slope toe part removal step for removing a slope toe part 111 of the existing banking 110 erected on top of a foundation ground B; a foundation ground excavation step underneath the slope toe for forming an excavated region A3 underneath the slope toe part 111 and an outer periphery of the slope toe part 111; a non-liquefaction integral structure installation step for installing a non-liquefaction integral structure 120 comprising crushed stones 121, 123 and a reinforcing sheet 122, in the excavated region A3; and a banking collapse suppression weight installation step for installing a banking collapse suppression weight 130 comprising a gabion 132, a cobblestone 133 and a covering fill 134, on top of the non-liquefaction integral structure 120. The reinforcing sheet 123 is made of a sheet-form geosynthetics or a wire net.SELECTED DRAWING: Figure 14 【課題】地震の際に基礎地盤が液状化を起こす場合であっても基礎地盤上の既設盛土における外縁の変形を抑制する非液状化一体構造体の一体性を強化した既設盛土の液状化対策メンテナンス工法を提供すること。【解決手段】基礎地盤Ｂの上方に造成された既設盛土１１０の法尻部１１１を撤去する法尻部撤去工程と、法尻部１１１とこの法尻部１１１の外縁との下方に掘削領域Ａ３を形成する法尻下方基礎地盤掘削工程と、掘削領域Ａ３に砕石１２１、１２３と補強シート１２２とからなる非液状化一体構造体１２０を設置する非液状化一体構造体設置工程と、非液状化一体構造体１２０の上方にふとん籠１３２と栗石１３３と押え盛土１３４とからなる盛土崩れ抑止重し１３０を設置する盛土崩れ抑止重し設置工程とを備え、補強シート１２３が、シート状のジオシンセティックスまたは金網からなること既設盛土１１０の液状化対策メンテナンス工法。【選択図】図１４