Analytical Evaluation on Soil Slope Reinforced by Pressure Grouted Protrusion Type Soil Nailing

Cheor-Hwa Hong; Sang-Duk Lee

doi:10.7843/kgs.2017.33.7.5

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2017 Vol.33, Issue 7 Next Page

Analytical Evaluation on Soil Slope Reinforced by Pressure Grouted Protrusion Type Soil Nailing 가압식 돌기네일에 의해 보강된 토사 비탈면의 해석적 평가

31 July 2017. pp. 5-16

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Abstract

Soil nailing is the most general method to reinforce the slope by taking pullout and shear resistance force of the nail for stabilizing the slope. Domestic soil nailing design method considers only pullout resistance and does not consider the shear resistance sufficiently. In case of nail, the effect of tensile stress is dominant, but it is desirable to design by considering shear stress as well as tensile stress in case of slope where circle failures occur. Recently, studies on the shear resistance effect of nails have been carried out in the geotechnical field. However, many researches on the shear reinforcement effect of soil nailing have not been conducted until now. Most of the studies are about increasing pullout resistance by improving material, shape and construction method of nail. Therefore, it is necessary to the study on shear resistance of soil nailing and development of new methods to increase the shear force. In this study, large shear test and limit equilibrium analysis have been performed for a new soil nailing method to increase the shear resistance by forming protrusions through pressurized grouting after installing a packer on the outside of deformed bar. The study results showed that shear resistance of protrusion type soil nailing increased compared to soil nailing and it is more effective when applied to the ground with large strength parameters.

Keywords

Soil nailing

Pressure grouted protrusion type soil nailing

Shear force

Large shear test

쏘일 네일링 공법은 비탈면 안정을 위해 네일의 인발 및 전단저항력을 이용하여 비탈면을 보강하는 가장 일반적인 공법이다. 국내의 쏘일 네일링 설계법은 인발저항만을 고려하고 전단저항에 대한 고려가 충분히 이루어지고 있지 않다. 네일의 경우 인장응력에 의한 효과가 지배적이나 원호파괴가 일어나는 비탈면의 경우 전단응력까지 고려하여 설계하는 것이 바람직하다. 최근 지반분야에서 네일의 전단저항 효과에 관한 연구들도 진행되고 있다. 하지만 아직까 지는 쏘일 네일링의 전단보강 효과에 관한 연구는 많이 이루어지고 있지 않은 실정이다. 대부분이 네일의 재료, 형상, 시공방법 등의 개선을 통한 인발저항 증대에 관한 연구이다. 따라서 쏘일 네일링의 전단저항에 대한 연구 및 전단력을 증대시킬 수 있는 새로운 공법개발이 필요한 실정이다. 본 연구에서는 이형철근 외측에 패커를 설치한 후 가압식 그라우팅을 통해 돌기를 형성함으로써 전단저항력을 증대시킬 수 있는 새로운 쏘일 네일링 공법에 대하여 대형전단시 험 및 한계평형해석을 수행하였다. 연구결과 돌기네일의 전단저항력은 일반네일에 비해 향상되였으며, 강도정수가 큰 지반에 적용하였을 때 효과적임을 확인할 수 있었다.

References

Anthonie (1987), “Stabilité D'une Fouille Renforcée Par Clouage”, Proc., 4th Franco-polish Conference on Applications of Soil Mechanics, Grenoble, France.

Frank, R. and Zhao, S. R. (1982), “Estimating the Settlement of Axially Loaded Bored Piles in Fine Sand by PMT Data”, (in French) Bull, Liaison LPC No.119 Paris.

Jewell, R. A. and Wroth, C. P. (1987), “Direct Shear Tests on Reinforced Sand, Geotechnique”, Vol.37, No.1, pp.53-68.

Marchal, J. (1984), “Reinforcement Des Sols Par Clouage – Etude Experimentale en Laboratoire”, Proc Int Conf on In-situ Soil and Eock Eeinforcement, Paris, pp.275-278.

Ortigao, J. A. R., Palmeira, E. M., and Zirlis, A. C. (1995), “Experience with Soil Nailing in Brazil: 1970-1994”, Proceeding of the Institution of Civil Engineers : Geotechnical Engineering Vol.113, Issue 2, pp.93-106.

Plumelle, C. and Schlosser, F. (1991), “Three Full-Scale Experiments of French Project on Soil Nailing: CLOUTERRE”, Transportation research record 1330, pp.80-86.

Schlosser, F. (1982), “Behavior and Design of Soil Nailing”, Proc., Symposium for Recent Developments in Ground Improvement Techniques, Bangkok, Thailand, pp.399-413.

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 :7
Pages :5-16
Received Date : 2017-01-20
Accepted Date : 2017-07-04
DOI :https://doi.org/10.7843/kgs.2017.33.7.5

Journal of the Korean Geotechnical Society ISSN:1229-2427(Print) 2288-646X(Online) 한국지반공학회 논문집

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