2019 Fiscal Year Final Research Report
Development of liquefied soil improvement method under existing building using microbial ureolysis
| Project/Area Number |
17H03348
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Building structures/Materials
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| Research Institution | Kajima Technical Research Institute, Kajima Corporation |
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Principal Investigator |
SUZUKI Yasutsugu 鹿島建設株式会社(技術研究所), 都市防災・風環境グループ, 専任部長 (70416767)
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| Co-Investigator(Kenkyū-buntansha) |
上野 嘉之 鹿島建設株式会社(技術研究所), 地球環境・バイオグループ, 上席研究員 (60416724)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Keywords | 地盤工学 / 地盤改良 / 液状化 / 微生物 / 地震 / せん断波速度 |
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| Outline of Final Research Achievements |
Elementary experiments were occurred under different conditions such as concentration, curing period and temperature using microorganisms collected from the ground all over Japan, calcium and nutrient sources. As a result, solidification of sandy ground, the degree and time until solidification were confirmed. At the same time, the optimum composition and conditions of the improvement liquid required for application to the in-situ ground were understood.
Improving liquid was injected into the ground by applying the wellpoint method and simultaneously pumped up from the opposite side separated by several meters. It was confirmed that the intermediate ground between the pumping and injection point separated by several meters could be improved. In addition, the improvement range was estimated from the value of the Fourier spectrum ratio in the high frequency region of the microtremor measurement results performed on the surface of the in-situ ground before and after the ground improvement.
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| Free Research Field |
地盤工学
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| Academic Significance and Societal Importance of the Research Achievements |
既存構造物直下地盤の液状化対策は，曲がりボーリングで薬液を注入する高価な工法しか存在しない。本手法は，構造物の片側から安価な改良液を安価な手法で地中に注入し，反対側から地下水を揚水することで構造物直下に改良液を拡散・滞留させ，元々地中に存在する微生物の代謝を利用して砂地盤の液状化強度を高めるものであり，安価な工法である。本工法により，これまで高コストであきらめていた既存構造物直下地盤や周辺地盤の液状化対策が可能になる。
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