All Issue

2025 Vol.27, Issue 2 Preview Page

Research Paper

Hydraulic behavior of Multi-purpose Micropile for tunnel floor heave reduction

터널 바닥부 융기 저감을 위한 배수겸용 마이크로파일의 수리 거동 분석

Hyun Il You1
,
Do-Hee Kim2
,
Seung-Hyun Kim3
,
Jae-Ho Jeong4
,
Jong-Ho Shin5*
유 현일1
,
김 도희2
,
김 승현3
,
정 재호4
,
신 종호5*
1Master Student, Dept. of Civil Engineering, Konkuk University
2Master, Dept. of Civil Engineering, Konkuk University
3Ph.D. Candidate, Dept. of Civil Engineering, Konkuk University
4CEO, GEO EXPERT GROUP Co., Ltd.
5Professor, Dept. of Civil and Environmental Engineering, Konkuk University
1학생회원, 건국대학교 인프라시스템공학과 석사과정
2비회원, 건국대학교 인프라시스템공학과 석사
3학생회원, 건국대학교 인프라시스템공학과 박사수료
4정회원, (주)지오엑스퍼트 그룹 대표이사
5정회원, 건국대학교 사회환경공학부 정교수
*Corresponding Author
31 March 2025. pp. 135-155
PDF XML Citation
Abstract

Recently, floor heave in operational tunnels has increasingly been reported as a threat to both stability and usability. Among the ground conditions where heave occurs, fault fracture zones, in particular, can induce floor heave due to their squeezing behavior or direct water pressure caused by high permeability. As countermeasures, micropiles for ground reinforcement and drainage pipes for reducing water pressure are commonly used. In this study, a Multi-purpose Micropile was introduced, combining the load-bearing function of micropiles with the hydraulic pressure relief function of drainage pipe to enhance economic feasibility and efficiency. To verify its hydraulic behavior, model tests and numerical analyses were conducted. The results show that the micropile installed at the floor effectively reduced hydraulic pressure while maintaining adequate water inflow. Decrease in the transverse spacing between micropiles proved to be an effective way for further hydraulic pressure reduction. However, beyond a certain spacing threshold, increasing the length of the drainage pipe is more effective.

Keywords
Tunnel heave
Multi-purpose Micropile
Water pressure
Hydraulic behavior

운영 중인 터널에서 바닥부 융기가 발생하여 안정성과 사용성을 위협하는 사례가 최근 다수 보고되고 있다. 특히, 융기가 발생한 지반 중 단층파쇄대는 압착성 거동을 하거나 높은 투수성으로 인해 바닥부에 직접적으로 수압이 작용할 수 있다. 이에 대한 대책으로는 지반 보강을 위한 마이크로파일과 수압 저감을 위한 배수공이 활용된다. 본 연구에서는 경제성과 효율성을 고려하여 마이크로파일의 지지기능과 배수공의 수압해제기능을 결합한 배수겸용 마이크로파일을 제안하였다. 이의 수리거동을 검증하기 위해 모형시험 및 수치해석을 수행한 결과, 바닥부에 설치한 경우, 수압저감효과가 뛰어나고 유입량도 적정한 수준을 유지하는 것으로 나타났다. 추가적인 수압저감효과를 얻기 위해서는 마이크로파일의 횡간격을 줄이는 것이 효과적이나 일정 간격 이하에서는 배수공 길이를 늘리는 방안이 효율적이다.

키워드
터널 융기
배수겸용 마이크로파일
저면수압
수리거동
References
1

Fang, X., Yang, J., Xiang, M., Zhang, X., Li, L. (2022), "Model test and numerical simulation on the invert heave behaviour of high-speed railway tunnels with rainstorm", Transportation Geotechnics, Vol. 37, pp. 1-16.

10.1016/j.trgeo.2022.100891
2

Joo, E.J., Shin, J.H. (2014), "Relationship between water pressure and inflow rate in underwater tunnels and buried pipes", Géotechnique, Vol. 64, No. 3, pp. 226-231.

10.1680/geot.12.P.185
3

Kim, K.C., Kim, H.J., Jung, Y.H., Shin, J.H. (2017), "Anchorage mechanism of inflatable steel pipe rockbolt depending on rock stiffness", Journal of Korean Tunnelling and Underground Space Association, Vol. 19, No. 2, pp. 249-263.

10.9711/KTAJ.2017.19.2.249
4

Lee, C.H., Wang, T.T., Sun, L.J., Huang, T.H. (2013), "Invert heaving in operational tunnels-problems and countermeasures", Proceedings of the World Tunnel Congress, Geneva, pp. 770-777.

10.1201/b14769-106
5

Luo, Y., Yang, J., Xie, Y., Fu, J., Zhang, C. (2024), "Investigation on evolution mechanism and treatment of invert damage in operating railway tunnels under heavy rainfall", Bulletin of Engineering Geology and the Environment, Vol. 83, No. 5, pp. 1-20.

10.1007/s10064-024-03655-4
6

Seo, Y.S., Yun, H.S., Kim, D.G., Kwon, O.I. (2016), "Analysis on physical and mechanical properties of rock mass in Korea", The Journal of Engineering Geology, Vol. 26, No. 4, pp. 593-600.

10.9720/kseg.2016.4.593
7

Shin, H.S., Youn, D.J., Chae, S.E., Shin, J.H. (2009), "Effective control of pore water pressures on tunnel linings using pin-hole drain method", Tunnelling and Underground Space Technology, Vol. 24, No. 5, pp. 555-561.

10.1016/j.tust.2009.02.006
8

Son, Y., Kim, N., Min, K. (2015), "A study on behaviour of tunnel considering the location of groundwater leaching and fault fracture zone under tunnel construction", Journal of the Korean Geo-Environmental Society, Vol. 16, No. 12, pp. 37-43.

10.14481/jkges.2015.16.12.37
9

Wang, Y., Jing, H., Su, H., Xie, J. (2017), "Effect of a fault fracture zone on the stability of tunnel-surrounding rock", International Journal of Geomechanics, Vol. 17, No. 6, pp. 1-20.

10.1061/(ASCE)GM.1943-5622.0000837
10

Wong, I.H. (2001), "Methods of resisting hydrostatic uplift in substructures", Tunnelling and Underground Space Technology, Vol. 16, No. 2, pp. 77-86.

10.1016/S0886-7798(01)00037-2
11

Zhang, Z., Chen, B., Li, H., Zhang, H. (2022), "The performance of mechanical characteristics and failure mode for tunnel concrete lining structure in water-rich layer", Tunnelling and Underground Space Technology, Vol. 121, 104335.

10.1016/j.tust.2021.104335
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 : 27
  • No :2
  • Pages :135-155
  • Received Date : 2025-02-17
  • Revised Date : 2025-03-15
  • Accepted Date : 2025-03-15
  • DOI :https://doi.org/10.9711/KTAJ.2025.27.2.135
Journal Informaiton Journal of Korean Tunnelling and Underground Space Association Journal of Korean Tunnelling and Underground Space Association
Online Submission & Review System
  • NRF
  • KOFST
  • KISTI Current Status
  • KISTI Cited-by
  • crosscheck
  • orcid
  • open access
  • ccl
Journal Informaiton Journal Informaiton - close