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2022 Vol.24, Issue 6 Preview Page

Research Paper

Pillar stability in very near-twin tunnels

초근접 병설터널의 필라 안정성 확보

Donggyou Kim1*
,
Sungyil Koh2
,
Jeongyong Lee3
,
Chulhee Lee4
김 동규1*
,
고 성일2
,
이 정용3
,
이 철희4
1Research Fellow, Korea Institute of Civil Engineering and Building Technology
2Representative Director, SEOHA Engineering and Construction
3Resident, Sambo Engineering Co., Ltd.
4Senior Research, Korea Institute of Civil Engineering and Building Technology
1정회원, 한국건설기술연구원 연구위원
2정회원, (주)서하기술단 대표이사
3정회원, (주)삼보기술단 사장
4정회원, 한국건설기술연구원 수석연구원
*Corresponding Author
30 November 2022. pp. 699-714
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Abstract

The objective of this study is to suggest a safe and economical pillar reinforcement method when very near-twin tunnels with a minimum interval of 1 m passes through a soft zone such as weathered soil or weathered rock. A standard cross-sectional view of a two-lane road tunnel was applied to suggest a pillar reinforcement method for the very near-twin tunnels. The thickness of the pillar was 1 m. The ground condition around the tunnel was weathered soil or weathered rock. There were four reinforcement methods for pillar stability evaluation. These were rock bolt reinforcement, pre-stressed steel strand reinforcement, horizontal steel pipe grouting reinforcement, horizontal steel pipe grouting + prestressed steel strand reinforcement. When the ground condition was weathered soil, only the pillar reinforced the horizontal steel pipe grouting + prestressed steel strand did not failed. When the ground condition was weathered rock, there were no failure of the pillar reinforced the horizontal steel pipe grouting or the horizontal steel pipe grouting + prestressed steel strand. It is considered that the horizontal steel pipe grouting reinforcement played a role in increasing the stability of the upper part of the pillar by supporting the upper load applied to the upper part of the pillar.

Keywords
Very near-twin tunnels
Pillar
Horizontal steel-pipe reinforcement
Numerical analysis

본 연구의 목적은 2개 터널의 간격이 최소 1 m이내인 초근접 병설터널이 풍화토 또는 풍화암같은 연약대를 통과하는 경우에 대해 안전하며 경제적인 필라보강방법을 제시하는데 있다. 초근접 병설터널의 필라부 보강방법 제시를 위하여 2차로 도로터널 표준단면도를 적용하였다. 필라부의 두께는 1 m로 가정하였다. 터널 통과 주변 지반 조건으로 풍화토 또는 풍화암으로 가정하였다. 필라부 안정성 평가를 위하여 4가지 보강 방법, 록볼트 보강, pre-stress 강연선 보강, 필라부 상부 수평강관 보강 + 그라우팅 보강, 수평 강관 보강 + 그라우팅 + pre-stress 강연선 보강 조건에 대하여 검토하였다. 터널 주변 지반조건이 풍화토인 경우 수평강관 보강 + 그라우팅 + pre-stress 강연선 보강 조건만 필라부에서 파괴가 발생하지 않았다. 터널 주변 지반조건이 풍화암인 경우 수평강관 보강 + 그라우팅 조건과 수평강관 보강 + 그라우팅 + pre-stress 강연선 보강 조건인 경우에서만 필라부에서 파괴가 발생하지 않았다. 수평강관 보강 + 그라우팅은 필라부 상부에 가해지는 상부하중을 지지하여 필라부 상부의 안정성을 증가시키는 역할을 수행한 것으로 판단된다.

키워드
초근접 병설터널
필라부
수평강관 보강공법
수치해석
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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 : 24
  • No :6
  • Pages :699-714
  • Received Date : 2022-11-01
  • Revised Date : 2022-11-15
  • Accepted Date : 2022-11-24
  • DOI :https://doi.org/10.9711/KTAJ.2022.24.6.699
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