報告書番号

U91066

タイトル（和文）

電気比抵抗による薬液注入改良効果の定量的評価方法（その１）－薬液充填率の評価法の開発－

タイトル（英文）

METHOD FOR EVALUATING CHEMICAL GROUTING BASED ON ELECTRICAL RESISTIVITY-EVALUATION OF GROUT RATIO OCCUPANCY VOID-

概要 （図表や脚注は「報告書全文」に掲載しております）

都市地上部における利用可能空間の減少に伴い，送電線洞道をはじめとする都市インフラストラクチャーが地下に建設される機会が増大している。このような都市地下構造物の建設においてはシードル工法や薬液注入による地盤改良工法が頻繁に利用される。しかし，薬液注入工法は注入後の改良効果（地盤の強度増加，止水性向上）の確認方法が未だ確立されていない等の問題を有している。本研究では室内試験により，薬液注入後の固結砂の電気比抵抗と薬液充填率は良い相関性を有していることを示した。この実験事実から電気比抵抗による薬液充填率の評価が可能であると考え，固結砂の電気伝導機構をモデル化し，注入前後の電気比抵抗の変化から薬液充填率を簡易に精度良く求める方法を提案した。さらに固結砂の薬液充填率を知ることにより間接的に薬液注入による強度増加の把握できることを示した。

概要 （英文）

AVAILABLE SPACE IS DECREASING IN LARGE CITIES AND UNDERGROUND AREAS ARE ATTRACTING INCREASING ATTENTION. CHEMICAL GROUTING IS FREQUENTLY USED AS AN AUXILIARY METHOD WHEN UNDERGROUND STRUCTURES SUCH AS SHIELD TUNNELS ARE CONSTRUCTED IN LARGE CITIES. HOWEVER,IT IS DIFFICULT TO EVALUATE THE QUALITIES OF AREAS SOLIDIFIED BY CHEMICAL GROUTING. TO SOLVE THIS PROBLEM,WE NOTED THAT THE ELECTRICAL RESISTIVITY OF CHEMICAL GROUT IS MUCH LOWER THAN THE RESISTIVITIES OF GROUND AND GROUNDWATER AND WE INVESTIGATED THE POSSIBILITY OF EVALUATING VOID FILLING BY ELECTRICAL RESISTIVITY. A SERIES OF ELECTRICAL RESISTIVITY TESTS. WERE PERFORMED ON SATURATED SANDS AND GROUTED SANDS; UNIAXIAL COMPRESSION TESTS WERE ALSO PERFORMED ON GROUTED SANDS IN THE LABORATORY. THE FOLLOWING CONCLUSIONS WERE OBTAINED: (1)ELECTRICAL RESISTIVITY TESTSON GROUTED SANDS SHOWED THAT THE ELECTRICAL RESISTIVITIES OF GROUTED SANDS ARE STRONGLY DEPENDENT ON THE VOLUME RATIO ALPHA OF GROUT OCCUPYING THE VOID SPACE OF SANDS. (2)ELECTRICAL-RESISTIVITY MODELS OF SATURATED SAND AND GROUTED SAND WERE PROPOSED,AND A METHOD FOR EVALUATING THE VOLUME RATIO ALPHA OF GROUT OCCUPYING THE VOID SPACE OF SANDS WAS SUGGESTED. (3)THE UNIAXIAL COMPRESSION TESTS SHOWED THAT THE REINFORCEMENT OFGROUTED SANDS IS STRONGLY DEPENDENT ON THE VOLUME RATIO ALPHA OF GROUTAND ON THE CONTINUITY OF GROUT OCCUPYING THE VOID SPACE OF SANDS.

報告者

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