Development of Up-flow percolation test method for impermeable materials for effective use of separated tsunami sediment

Research Project

Project/Area Number	17K06564
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Geotechnical engineering
Research Institution	Aichi Institute of Technology
Principal Investigator	NAKAMURA Yoshio 愛知工業大学, 工学部, 教授 (90784538)
Co-Investigator(Kenkyū-buntansha)	肴倉宏史国立研究開発法人国立環境研究所, 資源循環・廃棄物研究センター, 室長 (70331973)
Project Period (FY)	2017-04-01 – 2020-03-31
Project Status	Completed (Fiscal Year 2019)
Budget Amount *help	¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000) Fiscal Year 2019: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000) Fiscal Year 2018: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000) Fiscal Year 2017: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Keywords	津波堆積物 / 難透水性材料 / カラム通水試験 / 透水係数 / 溶出特性 / カラム試験 / 津波堆積物分別土砂 / 上向流カラム試験 / 締固め土 / 浸透流 / 環境安全性
Outline of Final Research Achievements	This study examines an Up-flow percolation test method for impermeable soils.1) Compared to permeable soils,the time for contact between soil and solvent is longer for impermeable soils, so the elution is complete in the range where the cumulative L/S is low.2) Water flow under constant hydraulic gradient condition is an effective method for clarifying the elution behavior of impermeable soils because it is possible to confirm the seepage behavior by separating both factors of coefficient of permeability and hydraulic gradient.3)On the other hand,in the case of sediment containing a large amount of fine particles, the permeability may decrease during water flow due to changes in the soil structure due to the electrification characteristics of the soil and the adsorption of ions. In order to obtain stable ground environment parameters,it was clarified that an Up-flow percolation test under the constant flow rate condition where the water flow rate was easy to control was advantageous.
Academic Significance and Societal Importance of the Research Achievements	津波堆積物分別土砂の有効利用に向けた環境安全性の評価手法の確立が求められている。津波堆積物土砂は、細粒分を含み、難透水性を呈することが少なからず確認されている。土壌の環境安全性を科学的根拠に基づき評価する手法の一つとしてカラム試験が挙げられ、広く実施されているが、透水性の低い土砂に対するカラム試験の方法は確立していない。本研究で検討した難透水性材料を対象としたカラム試験の有効性・適用性の評価は、分別土砂地盤に含まれる重金属等の有害物質の”環境受容性”を判断するための試験方法を確立する上で、また、復興資材等の品質管理や環境安全性の評価手法の展開に一助を加えたと考えている。