Journal of the Korean Geosynthetics Society (한국지반신소재학회논문집)

Korean Geosynthetics Society (한국지반신소재학회)
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Characteristic of Coastal Soil Improvement by MICP Technology Using Sea Water

해수를 사용한 MICP 기술의 연안 지반 개량시 발생하는 특성 분석

  • Sojeong Kim (Department of Ocean Civil Engineering, Gyeongsang National University) ;
  • Jinung Do (Department of Ocean Civil Engineering, Gyeongsang National University)
  • Received : 2023.04.26
  • Accepted : 2023.06.02
  • Published : 2023.06.30
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Abstract

Mean sea level has recently been rising due to global warming causing coastal erosion. As Korea is peninsula, the land loss due to coastal erosion is critical. An approach in this study is cementing the coastal area using bacteria, which is called microbially induced carbonate precipitation (MICP). This study tried to see how fresh water and sea water work with MICP as a solvent. Ureolytic activity during the MICP reaction was measured with deionized and sea water. A soil column was prepared to evaluate the strength of MICP-treated sand. Sands were treated by MICP with surface percolation method. As the treatmen t style was different with other conventional methods, several methods were proposed to properly evaluate the MICP-treated sand surface. A micro-scale evaluation was performed to assess the mineral structure treated by different solvents. As results, sea water rendered the ureolytic reaction slower. A needle penetrometer worked well to evaluate the MICP-treated sand surface. This study confirmed the utilization of sea water is feasible as the solvent of MICP.

최근 지구온난화 등으로 인하여 지구의 평균해수면이 상승하는 추세이다. 삼면이 바다인 국내의 경우 연안침식이 초래되어 국토 손실 및 연안의 위험성을 높일 가능성이 있다. 미생물에 의한 탄산칼슘 형성(MICP) 기술은 미생물에 의한 탄산칼슘침강 기술이며, 지반의 강성과 강도를 증진시키는 친환경적 방법이다. 본 연구에서는 연안 침식 저감을 위하여 MICP 기술을 제안하였다. 연안 조건을 고려하여 용매로 해수를 사용하고 탈염수와 그 성능을 비교하였다. 탈염수와 해수 조건하에서 미생물에 의한 요소분해능을 조사하였다. 소일칼럼을 제작하여 MICP 처리된 모래의 강도 평가를 실시하였다. MICP 처리는 표면살포법에 의해 처리되었는데, 이러한 방식은 기존의 혼합 방식과 달라 전통적인 강도 평가 방식은 적절하지 않음을 확인하였다. 미세 구조 분석을 통해 다른 용매가 사용된 경우의 광물적 변화를 관측하였다. 실험 결과, 해수는 미생물에 의한 요소분해 반응을 느리게 만드는 것을 확인하였다. 표면 경화된 모래는 침관입시험을 통해 효과적으로 평가할 수 있었다. 이 연구에서는 해수를 용매로 사용하여도 탈염수 수준으로 충분히 MICP 기술 적용이 가능함을 확인하였다.

Keywords

Acknowledgement

This work was supported by the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education (2021R1I1A3049493).

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