3-Dimensional numerical analysis on support performance of early-high-strength shotcrete

Jong-Uk Kim; Jung-Joo Kim; Young-Jae Cho; Han-Kyu Yoo

doi:10.9711/KTAJ.2014.16.5.459

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2014 Vol.16, Issue 5 Preview Page Next Page

3-Dimensional numerical analysis on support performance of early-high-strength shotcrete 3차원 수치해석을 이용한 조기고강도 숏크리트 지보성능 분석

30 September 2014. pp. 459-470

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Abstract

Now-a-days, the trend in constructing tunnels is to build more deeper, more longer tunnels of greater cross-sections. That’s why, the demand of “Early-high-strength shotcrete” is very high because of their advantage of attaining higher strength immediately after excavation, which controls the ground subsidence. So, this study reveals the supporting phenomena of early-high-strength shotcrete, using three-dimensional numerical analysis. The crux of this study can be applied practically in construction sites also. Support Performance of two different qualities of shotcrete was checked out, by keeping the general shotcrete’s thickness constant and comparing it with early-high-strength shotcrete’s thickness decreasing it gradually in five steps, and analysing/comparing the support performance in all cases. Effect of using early-high-strength shotcrete was analysed to save the cost of steel sets, which are widely used for supporting the ground before the hardening of general shotcrete. The results of numerical analysis on the performance of early-high-strength shotcrete show that, it behaves more effectively under worse ground conditions and it can support the ground more conveniently than steel sets, before the shotcrete is hardened.

Keywords

Shotcrete

Early-High-Strength Shotcrete

Steel sets

Support effect

Hardening characteristic

최근 터널의 건설심도는 점차 깊어지고 길이 및 단면은 증가하는 추세를 보이고 있다. 따라서 굴착 직후 주변 지반의 지압에 대해 보다 높은 지보효과를 발휘하고 지표침하 억제효과가 있는 조기고강도 숏크리트에 대한 필요성이 증대되고 있다. 따라서 본 논문에서는 3차원 수치해석을 통해 조기고강도 숏크리트의 지보성능을 분석하여 실제 현장에서의 적용가능성을 높이고자 일반 숏크리트와 같은 지보효과를 발휘하는 조기고강도 숏크리트 라이닝의 두께를 추정하기 위해서 조기고강도 숏크리트 라이닝의 두께를 5단계로 변경하며 해석을 수행하여 지보성능을 분석하였다. 또한 숏크리트가 경화될 때까지 지반을 지지하기 위하여 설치하는 강지보재를 조기에 강도발휘가 가능한 조기고강도 숏크리트로 대체할 수 있는 가능성을 판단하였다. 수치해석 결과, 조기고강도 숏크리트는 지반조건이 불리할수록 지반변위 억제 효과가 증대되며 강지보재의 숏크리트 경화 전 지보효과를 보완할 수 있을 것으로 판단하였다.

키워드

숏크리트

조기고강도 숏크리트

강지보재

지보효과

경화특성

References

1.Kanazawa, H., Nishi, T., Kiuchi, T., Nishizaki, S., Furuto, Y. (2007), “The development of early-high- strength shotcrete and the evaluation of improved tunnel support system.”, Underground Space, the 4th Dimension of Metropolises, pp. 1361-1367.

2.Kanazawa, H., Nishi, T., Nonomura, M., Nishizaki, S. (2010), “A study on rapid NATM tunnel driving by early-high-strength shotcrete support system.”, Japan Society of Civil Engineers, Vol. 66, No. 3, pp. 447-458.

3.Kim, S.H., Kim, K.L., Jeong, S.S., Choi, W.I., Lee, K.J., Lee, S.W. (2012), “Estimation of the Ground Loads Acting on Concrete lining in NATM Tunnel.”, Korean Society for Railway, Vol. 2012, No. 5, pp. 415-420.

4.Korean Tunneling Association (2009), A manual of tunnel design criteria, CIR, Korea, pp. 122-131.

5.Lee, S.J., Moon, H.K. (2000), “A study on the interaction between tunnel ground and shotcrete support considering time dependency.”, J. of the Korean Society of Mineral and Energy Resources Engineers, pp. 350-361.

6.Moon, S.H., Shin, Y.W., Kim, S.H., Yoo, H.K. (2012), “A Study on Load Bearing Capacity of Composite Member with Steel Rib and Shotcrete in NATM Tunnel.”, J. of the Korean Society of Civil Engineers, Vol. 32, No. 5, pp. 221-229.

Information

Publisher :Korean Tunneling and Underground Space Association
Publisher(Ko) :한국터널지하공간학회
Journal Title :Journal of Korean Tunnelling and Underground Space Association
Journal Title(Ko) :한국터널지하공간학회 논문집
Volume : 16
No :5
Pages :459-470
Received Date : 2014-08-26
Revised Date : 2014-09-15
Accepted Date : 2014-09-17
DOI :https://doi.org/10.9711/KTAJ.2014.16.5.459

Journal of Korean Tunnelling and Underground Space Association ISSN:2233-8292(Print) 2287-4747(Online) 한국터널지하공간학회 논문집

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