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2017 Vol.33, Issue 5
Constant Rate of Strain Consolidation Test with Rowe Cell on the Clay with Sand Seam

샌드심이 존재하는 점토에 Rowe Cell를 이용한 일정변형률 압밀시험

Jae-Hong Kim1
,
Chan-Kee Kim2
,
Tae-Hyung Kim3
김 재홍1
,
김 찬기2
,
김 태형3
1Member, Senior Researcher, Infrastructure Technology Center, KWIE, K-water
2Member, Prof., Dept. of Civil Engrg., Daejin Univ.
3한국해양대학교 건설공학과 교수 Member, Prof., Dept. of Civil Engrg., Korea Maritime and Ocean Univ
1한국수자원공사 기반시설연구소 선임연구원
2대진대학교 건설시스템공학과 교수
3정회원, ㈜삼보기술단 지반사업본부 기사
*교신저자. *Corresponding Author. 
31 May 2017. pp. 5-15
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Abstract

The sand layer deposited in clay is called a sand seam, which is formed by inflow of sands due to river flooding or slope failure in the middle of sinking and sediment of clay. When the sand seam exists in clay layer, the drainage direction changes from one way to both ways, and the time of consolidation may be reduced. However, it is not clearly proved due to lack of studies of sand seam and currently is not reflected in the design of soft soil improvement. As a fundamental study about sand seam, the oedometer tests and constant rate of strain tests with Rowe cell were conducted on clay specimens with sand seam. For tests, a frozen method was specially designed for making the sand seam. It was concluded that the test results showed the sand seam affects the coefficient of consolidation of clay. If the thickness of sand seam exceeds 0.05 times of specimen height, the sand seam works as drainage layer of pore water horizontally as well as vertically, and consequently the consolidation is accelerated.

Keywords
Sand seam
Rowe cell
Constant rate of strain consolidation
Coefficient of consolidation

샌드심(Sand seam)은 점성토 지층속에 모래층이 층상으로 존재하는 것으로 점토가 침강･퇴적하는 과정중에 하천의 범람이나 사면활동 등에 의하여 모래 성분이 유입되어 생성된 것으로 알려져 있다. 연약지반내에 샌드심이 존재할 경우 일방향 배수에서 양방향 배수가 되기 때문에 압밀시간이 단축이 가능하다 판단되어지나, 샌드심에 대해 연구가 국내외적으로 미진하여 연약지반개량 설계 시 이를 설계에 제대로 반영 못하는 실정이다. 본 연구는 샌드심에 대한 기초연구로 얇은 모래층(샌드심)이 존재하는 점토 시료에 대해 표준압밀시험과 Rowe cell을 이용한 일정변형률시험을 수행하였다. 시험을 위해 냉동법을 이용한 특별히 고안된 샌드심 제작방법을 제시하였다. 시험 결과 샌드심이 점토지 반에 존재 시 압밀계수에 영향을 줌을 알 수 있었다. 샌드심의 높이가 시료높이의 0.05배 이상이면 샌드심이 충분한 배수층 역할을 하여 간극수의 배수방향이 수평방향뿐만 아니라 수직배수가 함께 진행되어 압밀이 빠르게 진행되는 것으로 나타났다.

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Information
  • Publisher :The Korean Geotechnical Society
  • Publisher(Ko) :한국지반공학회
  • Journal Title :Journal of the Korean Geotechnical Society
  • Journal Title(Ko) :한국지반공학회 논문집
  • Volume : 33
  • No :5
  • Pages :5-15
  • Received Date : 2016-12-16
  • Accepted Date : 2017-05-18
  • DOI :https://doi.org/10.7843/kgs.2017.33.5.5
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