METHOD OF CONFIRMING GROUND IMPROVEMENT EFFECT AND MEASURING DEVICE USED FOR IT

To provide a method and a measuring device for confirming the effect of ground improvement that reduces variation, enables direct confirmation of the quality of improved ground, eliminates the risk that a measurement probe cannot be recovered in the electrical logging, and ensures that electrodes ar...

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Main Authors AKATSUKA MITSUHIRO, SHIMOZAKA KENJI, ITO TAKAYOSHI, MURATA YOSHINOBU, ONO YASUTOSHI
Format Patent
LanguageEnglish
Japanese
Published 14.01.2021
Subjects
EMBANKMENTS
EXCAVATIONS
FIXED CONSTRUCTIONS
FOUNDATIONS
HYDRAULIC ENGINEERING
SOIL SHIFTING
UNDERGROUND OR UNDERWATER STRUCTURES
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Summary:To provide a method and a measuring device for confirming the effect of ground improvement that reduces variation, enables direct confirmation of the quality of improved ground, eliminates the risk that a measurement probe cannot be recovered in the electrical logging, and ensures that electrodes are in contact with the hole wall.SOLUTION: After the ground improvement, a depth distribution map of the Nd value was obtained by a small dynamic cone penetration test, and the primary effect was confirmed to confirm the ground improvement effect. When the ground improvement effect is not recognized by the above primary effect confirmation, a measurement probe 2 equipped with an electrode is inserted into a penetration hole 1 of the small dynamic cone penetration test, and a depth distribution map of the specific resistance is obtained by an electrical logging for measuring the specific resistance. A secondary effect is confirmed to confirm the ground improvement effect from the amount of resistivity reduction before and after the ground improvement. In the electrical logging, when a hollow outer sleeve is detachably inserted into the measurement probe 2 and it becomes difficult to pull it out from the penetration hole 1, the measurement probe 2 can be removed from the outer sleeve and recovered.SELECTED DRAWING: Figure 1 【課題】バラツキを少なくし、改良地盤の品質を直接的に確認できるようにし、電気検層における測定プローブの回収不能リスクを無くし、電極を孔壁に確実に接触できる、地盤改良効果の確認方法並びに測定装置を提供する。【解決手段】地盤改良後において、小型動的コーン貫入試験によりNd値の深度分布図を得て、地盤改良効果を確認する１次的効果確認を行い、前記１次的効果確認によって地盤改良効果が認められない場合に、小型動的コーン貫入試験の貫入孔１に電極を備えた測定プローブ２を挿入して比抵抗を測定する電気検層により比抵抗の深度分布図を得て、地盤改良前後における比抵抗の減分量から地盤改良効果を確認する２次的効果確認を行う。電気検層において、測定プローブ２に中空状の外装スリーブが着脱可能に挿嵌され、貫入孔１から引き抜くことが困難になった場合に、測定プローブ２が外装スリーブから抜けて回収できる。【選択図】図１
Bibliography:Application Number: JP20190118064