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2020 Vol.22, Issue 2

Research Paper

Determination of equivalent elastic modulus of shotcrete-tetragonal lattice girder composite

사변형 격자지보재-숏크리트 합성부재의 등가물성 결정 기법

Kyung-Nam Kang1
,
Ki-Il Song2*
,
Sun Gil Kim3
,
Kyoung Chul Kim4
강 경남1
,
송 기일2*
,
김 선길3
,
김 경철4
1Graduate Student, Dept. of Civil Engineering, Inha University
2Associate Professor, Dept. of Civil Engineering, Inha University
3Associate Research, Civil Infrastructure Research Division, Kolon Global Corporation
4Principal Researcher, Civil Infrastructure Research Division, Kolon Global Corporation
1학생회원, 인하대학교 토목공학과 박사과정
2정회원, 인하대학교 토목공학과 부교수
3비회원, 코오롱글로벌 기술연구소 전임연구원
4비회원, 코오롱글로벌 기술연구소 책임연구원
* Corresponding Author
31 March 2020. pp. 145-154
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Abstract

Steel set is a structure that stabilize the NATM tunnel until the installation of shotcrete, and it is combined after the shotcrete is installed to improve stability. In this study, determination approach for the equivalent elastic modulus of shotcrete-lattice girder composite is newly suggested for tunneling simulation. Also, a method was presented to calibrate the equivalent elastic modulus through the comparison of the full 3D model and equivalent model. When the conventional equivalent elastic modulus is used for shotcrete-lattice girder composite, the flexural strength of equivalent model is 130% smaller than that of full 3D model. Equivalent elastic modulus is adjusted considering the error of flexural strength. It is found that the error of flexural strength obtained from adjusted equivalent model using adjusted equivalent elastic modulus is reduced less than 1%.

Keywords
Shotcrete
Equivalent elastic modulus
Lattice girder
Tetragonal lattice girder
Tunneling simulation

NATM 공법에 있어서 강지보재는 숏크리트가 타설되어 라이닝을 완전히 구성할 때까지 터널의 안정화를 확보하는 구조체로서, 숏크리트의 타설 전 뿐만 아니라 타설 후 숏크리트와의 일체 거동을 통해 라이닝의 강도를 더해주는 역할을 수행한다. 본 연구에서는 새로운 형식의 사변형 격자지보재를 터널의 안정해석에 적용하기 위한 방안으로 체적비 기반의 숏크리트와 강지보재 합성부재의 등가 물성치 결정법을 제시하였다. 사변형 격자지보재는 수직 및 수평 보강재의 존재로 면적비 기반으로 등가 물성치를 산정할 경우 선택한 단면에 따라 물성치가 상이 할 수 있다. 따라서 본 연구에서는 체적비 기반의 등가 물성치 결정법을 제시하였으며, 격자지보재와 숏크리트로 구성된 합성부재 요소에 대한 상세모델과 등가물성치를 사용한 등가모델의 비교를 통하여 등가탄성계수를 보정할 수 있는 방법을 제시하였다. 상세모델과 등가모델을 비교한 결과 등가모델은 상세모델에 비해 평균적으로 130% 작은 휨 강도를 나타내었다. 본 연구에서는 휨강도의 오차율을 고려하여 등가탄성계수를 보정할 수 있는 방법을 제시하였고, 보정된 등가탄성계수를 적용한 등가모델의 휨강도는 상세모델과 평균 오차율 1% 이내로 나타났다.

키워드
숏크리트
등가 탄성계
격자지보재
사변형 격자지보재
터널 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 : 22
  • No :2
  • Pages :145-154
  • Received Date : 2020-01-14
  • Revised Date : 2020-03-18
  • Accepted Date : 2020-03-20
  • DOI :https://doi.org/10.9711/KTAJ.2020.22.2.145
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