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2025 Vol.41, Issue 4 Preview Page
Boiling Stability Evaluation during Excavation in Alternating Sand–Clay Ground

사질토와 점성토가 교호하는 지반의 굴착공사시 보일링 안정성 평가

Hyeonsu Yun1
,
Seong-Kyu Yun2
,
Deokung Ma3
,
Ji-Gun Chang4
,
Gichun Kang5*
윤 현수1
,
윤 성규2
,
마 덕웅3
,
장 지건4
,
강 기천5*
1Member, Ph.D Candidate, Department of Civil Engineering, College of Engineering, Gyeongsang National Univ.
2Member, Ph D, Department of Civil Engineering, College of Engineering, Gyeongsang National Univ.
3Korea Land and Housing Corporation
4Member, Kwanglim Engineering&Construction Co., Ltd.
5Member, Associate Prof., Department of Civil Engineering, College of Engineering, Gyeongsang National Univ.
1정회원, 경상국립대학교 공과대학 토목공학과 박사과정
2정회원, 경상국립대학교 공과대학 토목공학과 공학박사
3비회원, 한국토지주택공사
4정회원, 광림엔지니어링
5정회원, 경상국립대학교 공과대학 토목공학과 부교수
*Corresponding Author
31 August 2025. pp. 65-75
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Abstract

With ongoing urbanization, the demand for underground space has increased, making the stability of ground excavation works increasingly critical. In alternating sand–clay ground, the risk of unexpected boiling phenomena is particularly high. In practice, Terzaghi’s simplified method and seepage analysis are commonly applied; however, the criteria for incorporating the cohesion of clay layers remain unclear, often resulting in under-design or overly conservative embedment depths. This study conducted seepage analysis of a construction site in Busan, incorporating permeability coefficients, seepage pressure locations, and clay cohesion. The results show that when the excavation bottom is composed of sand, the safety factor obtained from the simplified method is comparable to that from the seepage analysis, indicating the simplified method is suitable. However, when the excavation bottom is clay, the safety factor from the seepage analysis is lower, indicating the need for a more conservative design approach to ensure boiling stability.

Keywords
Alternating sand–clay ground
Boiling stability
Ground excavation

도시화에 따라 지하공간 개발이 증가하면서 지반 굴착공사의 안정성이 중요해지고 있다. 사질토와 점성토가 교호하는 지반에서는 보일링 현상의 발생 위험도가 높으며, 실무에서는 Terzaghi 간편식과 침투해석을 적용하여 보일링 안정성을 평가한다. 그러나 보일링 안정해석시 점토층의 점착력 적용 기준이 명확하지 않아 과소 설계 또는 과도한 근입깊이로 이어질 수 있다. 본 연구는 부산OO 건설현장을 대상으로 투수계수, 침투수압, 점착력을 반영한 침투해석을 수행하였다. 그 결과, 굴착저면이 모래층인 경우 간편식과 침투해석 결과가 유사해 간편식 적용이 가능하지만, 점토층의 경우 침투해석 결과가 더 낮아 보일링 안정성 확보를 위한 보수적 설계가 필요한 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 : 41
  • No :4
  • Pages :65-75
  • Received Date : 2025-06-17
  • Revised Date : 2025-07-07
  • Accepted Date : 2025-07-11
  • DOI :https://doi.org/10.7843/kgs.2025.41.4.65
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