Browse > Article
http://dx.doi.org/10.12814/jkgss.2018.17.1.111

A Case Study on the effects of Elephant Foot Method considering the rate of Changes in Tunnel Cross Section  

Lee, Gil-Yong (Department of Regional Infrastructure Engineering, Kangwon National University)
Oh, Hyeon-Mun (Department of Regional Infrastructure Engineering, Kangwon National University)
Cho, Kye-Hwan (Geotechnical and Tunnel Engineering Division, Chunil Engineering Consultants)
Oh, Jeong-Ho (Department of Railroad Infrastructure System Engineering, Korea National University of Transportation)
Kim, Jong-Ju (Department of Regional Infrastructure Engineering, Kangwon National University)
Kim, Yong-Seong (Department of Regional Infrastructure Engineering, Kangwon National University)
Publication Information
Journal of the Korean Geosynthetics Society / v.17, no.1, 2018 , pp. 111-118 More about this Journal
Abstract
In case of excavation of the tunnel under weak ground conditions, such as fault zone, leg pile reinforcement with the purpose of suppressing tunnel crown settlement and side wall displacement is commonly applied. There are convergence, crown settlement, leg settlement, and the axial force of leg as a main factor for confirming the safety of support considering the installation angle and length of leg pile reinforcement according to the increase in rate of change of tunnel cross-section. In particular, the influence of right corner settlement, among variables for safety confirmation during excavation, has been analyzed as the dominant factor in the most important priority management showing larger displacement tendency than the increase in rate of the cross-section. And, it was analyzed that the occurrence tendency of axial force on leg pile reinforcement showed the influence of behavior according to the friction support concept mechanism of the pile reinforcement rather than the increase in rate of tunnel cross-section, as it showed a small increase compared to the increase rate of the tunnel cross-section which did not show a great correlation from the viewpoint of the change of the axial force by the length of each leg pile reinforcement with regards to the change in rate of increase in tunnel cross-section. If a certain length of the leg pile reinforcement is selected based on the above grounds, even if the cross-section of the tunnel in poor ground condition is somewhat larger, it has been proved to be a more reasonable method considering the workability and economical efficiency by not extending the length of the leg pile reinforcement by force.
Keywords
Leg pile reinforcement; Axial force; Settlement;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
연도 인용수 순위
1 Jung, H., Kim, H., Chun, B. (2009), "A study on the ground settlement and reinforcement measures in the case of tunneling at the yangsan fault." Journal of the Korean Geotechnical society, Vol.10, No.6, pp.35-48.
2 Lee, G.-Y., Oh, J.-H., Cho, K.-H., and Lee, D.-S. (2016), "A case study on elephant foot method for railway tunneling in large fault zone.", Journal of the Korean society of civil engineers, Vol.36, No.6, pp.1161-1167.   DOI
3 Lee, G.-Y. (2016). A case study on elephant foot method for tunneling in large fault zone. Ms. Thesis, Korea National University of Transportation.
4 Park, C., Lee, H., Park, J., Yoon, C., Hwang, J. (2009), "A Case study on elephant foot method for tunneling in the soft ground." Journal of the Korean Geotechnical Society, September 25-26, 2009, Incheon, Korea.
5 Shin, H. (2014). A study for tunneling excavation and reinforcement in excessive displacement ground characteristics. Ms. Thesis, Woosong University.
6 Yim, C. (2006), Optimum tunnel excavation and reinforcement method in large fault zones. Ms. Thesis, Korea University.
7 Yim, S., Seo, Y., Kim K., Kim C., Kim H. (2010), "Reinforcing Effect by Tunnel Support System." KSEG Conference, April 8-9, 2010, Kyeongju, Korea, pp.255-258.