Journal of the Korean Geosynthetics Society (한국지반신소재학회논문집)

Korean Geosynthetics Society (한국지반신소재학회)
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Evaluation of Shallow Foundation Behavior on Basalt Rock Layers With Clinker and Sediment Layers Reinforced Using Cement Grouting

현무암층 사이에 존재하는 클링커층과 퇴적층의 시멘트 그라우팅 보강에 따른 얕은 기초 거동 평가

  • Lee, Kicheol (Dept of Civil and Envirionmental Engineering, Incheon National University) ;
  • Shin, Hyunkang (Infrastructure Solution Group, Infra Division, POSCO E&C) ;
  • Jung, Hyuksang (Dept. of Railway Construction and Safety Engineering, Dongyang University) ;
  • Kim, Donghoon (City Planning Team of Jeju Urban Construction Department) ;
  • Ryu, Yongsun (Chemius Korea Co., Ltd.) ;
  • Kim, Dongwook (Dept of Civil and Envirionmental Engineering, Incheon National University)
  • Received : 2019.06.18
  • Accepted : 2019.09.16
  • Published : 2019.09.30
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Abstract

Clinker layer is a stratum structure distributed in volcanic area such as Jeju Island. The clinker layers were formed in between the repetitive action of eruption and solidification of lava flows. Since the clinker layer contains a large amount of voids accompanied by the lava gas ejection process, there is a possibility of inducing overall stability of the ground due to the low stiffness and strength of the clinker layer. Therefore, in this study, site investigation was carried out at both ends of the 00 bridge where the clinker layers exist. And, based on the ground survey results, the behavior of shallow foundations was analyzed numerically. In addition, the improved shallow foundation behavior in grouting substitution using the chemical injection method of the clinker layer was compared with the shallow foundation behavior in the ground, and the grouting substitution efficiency of each layer was analyzed. As a result, the bearing capacity, the replacement efficiency and elastic settlement were different according to the presence or absence of the sediment layer. This is because the sediment layer has a lower stiffness and density than the clinker layer.

클링커층은 제주도와 같은 화산지대에 분포하는 독특한 지층구조로 용암이 분출하며 고결되는 과정에서 생긴 클링커가 암반층 하부에 퇴적된 지층을 의미한다. 클링커층은 용암 가스의 분출과정에서 동반되는 다량의 공극을 포함하고 있기 때문에 지층 내 존재할 시 지반의 전체적인 안정성을 저해할 가능성이 존재하며 이에 대한 대처가 필요한 실정이다. 따라서 본 연구에서는 클링커층이 존재하는 00교의 시점 및 종점 부근에서 각 2공의 지반조사(총 4공)를 수행하였고, 지반조사결과를 토대로 얕은 기초 시공 시 거동을 수치해석적으로 검토하였다. 또한 클링커층의 약액주입공법을 통한 그라우팅 치환 시 개선된 얕은 기초 거동을 원지반에서의 얕은 기초 거동과 비교하고, 지층별 그라우팅 치환 효율을 분석하였다. 분석 결과, 클링커층보다는 기존 지반에 존재하는 퇴적층의 유무에 따라 지지력 및 치환 효율, 탄성 침하량에 차이가 발생하였으며, 이는 퇴적층이 상대적으로 클링커층보다 낮은 강성과 밀도를 가지고 있기 때문으로 판단된다.

Keywords

References

  1. Cas, R. A. F. and Wright, J. V. (1987), Volcanic Successions: Modern and Ancient. Allen and Unwin, London, 528 p.
  2. Chun, B., Park, D. and Lee, E. (2014), "A Study on the Ground Reinforcement of Jeju Island Scoria by Laboratory Grouting Test", Proceedings of Korean Geo-Environmental Society, pp.236-241. (in Korean)
  3. Gratchev, I. and Towhata, I. (2010), "Geotechnical characteristics of volcanic soil from seismically induced Aratozawa landslide, Japan", Landslides, Vol.7, No.4, pp.503-510. https://doi.org/10.1007/s10346-010-0211-2
  4. Kim, J. H. (2006), A study on the mechanical characteristics and the strength in Pyoseonri basalt, Thesis, Cheju National University. (in Korean)
  5. KS F 2307 (2017), Standard Test Method for Standard Penetration Test, KSA(Korean Standards Association). (in Korean)
  6. KS F 2317 (2016), Standard Test Method for Thin-Walled Tube Sampling of Soils, KSA (Korean Standards Association). (in Korean)
  7. MOLIT (2003), Comprehensive Report on Standard Drawing of Road Wall, MOLIT (Ministry of Land, Transport and Maritime Affairs). (in Korean)
  8. MOLIT (2012), Standard of Concrete and Structure, MOLIT (Ministry of Land, Transport and Maritime Affairs). (in Korean)
  9. MOLIT (2016), Soil Investigation of Site, MOLIT(Ministry of Land, Infrastructure, and Transport). (in Korean)
  10. Moon, V., Bradshaw, J., Smith, R., and de Lange, W. (2005), "Geotechnical Characterisation of Stratocone Crater Wall Sequences, White Island Volcano, New Zealand", Engineering Geology, Vol.81, No.2, pp.146-178. https://doi.org/10.1016/j.enggeo.2005.07.014
  11. Nam, J. M., Yun, J. M., Song, Y. S. and Kim, J. H. (2008), "Analysis of Engineering Properties to Basalt in Cheju island", Korean Geosynthetics Society, Vol.7, No.1, pp.13-21. (in Korean)
  12. Park, K. H., Ahn, J. S., Ki, W. S. and Park, W. B. (2006), Jeju Island Geological Travel, KIGMR(Korea Institute of Geoscience and Mineral Resources). (in Korean)
  13. Yang, G. H., Seo, S. D., Cho, Y. S. and Park, J. J. (2013), "Numerical Analysis of Offshore Wind Turbine Foundation Considering Properties of Soft layer in Jeju", Korean Geosynthetics Society, Vol.12, No.4, pp.45-56. (in Korean) https://doi.org/10.12814/jkgss.2013.12.4.045
  14. Yang, K., Park, J., Kim, Y., Byun, Y., Lee, E. and Chun, B. (2014), "A Study on the Ground Reinforcement of Jeju Scoria Layer by Chemical Grouting", Journal of the Korean Geoenvironmental Society, Vol.15, No.2, pp.75-82. (in Korean) https://doi.org/10.14481/jkges.2014.15.2.75