X線CTを用いたModified GIN工法導入地点でのグラウト浸透状況の可視化

Abstract

GIN工法をベースに注入材料の配合，注入圧力の設定，注入量制限を再考し，安全性・確実性に配慮したModified GIN工法が提案され，実際に施工された．本研究では，Modified GIN工法によるグラウトの充填状況を確認するため，実施地点よりグラウト充填ボーリングコアを採取し，医療用X線CTとμフォーカスX線CTによりCT画像の撮影および画像解析を行った．CT画像の分析により，割れ目内にグラウト材が充填されていること，割れ目の幅が大きくなれば，グラウト材が層をなして充填していることが確認された．割れ目幅の広いところは，先行して注入された濃度の薄いグラウト材に濃度の濃いグラウト材が繰り返し注入された結果である考えられ，このことは，実際の施工状況と一致することになる．

The Modified GIN method which arranged the mix proportion of the grouting material, the injected pressure and the amount of the injected grouting material and considered as the safety and the quality assurance has been developed and employed at a construction site. In order to evaluate the grouting performance through Modified GIN method, in this research, CT images of borehole core samples are taken through both medical X ray CT and -focus X ray CT and are analyzed. Based on the CT images, it is confirmed that the grouting material are filled into the aperture of fracture. In the wide aperture, it is also confirmed that the filling grouting material consists of some layers. In the actual construction, the low density grouting material was injected in the first step, and then the high density grouting material was injected if the proposed injected pressure was not arrived in the first step. It is thought, therefore, that the CT images show the good agreement with the actual construction process.