Journal of Korean Tunnelling and Underground Space Association (한국터널지하공간학회 논문집)

Korean Tunnelling and Underground Space Association (한국터널지하공간학회)
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A numerical study on the 3-Dimensional shape characteristics of small underground cavities

소규모 지하공동 3차원 형상 특성을 반영한 수치해석에 관한 연구

  • 안준상 ((주)베이시스소프트 건설IT연구소) ;
  • 강경남 (인하대학교 토목공학과) ;
  • 송기일 (인하대학교 토목공학과) ;
  • 김우석 (한국건설기술연구원 인프라안전연구본부) ;
  • 김병찬 ((주)베이시스소프트 건설IT연구소)
  • Received : 2018.06.20
  • Accepted : 2018.07.31
  • Published : 2018.09.30
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Abstract

When conducting the underground safety impact assessment under the special law in Korea, it is essential to investigate the occurrence of underground cavities. When underground cavities were discovered, the underground safety was assessed through numerical analysis. The previous study has suggested the stability evaluation based on the factor of safety by changing the 2D shape of the small underground cavity. In this study, the effects of small underground cavities considering 3D shapes were examined using a continuum analysis program and compared with the 2D results presented in previous study. If the 3-Dimensional shape of the underground cavity is found close to the sphere type, it would be reasonable to evaluate the factor of safety by the shear strength reduction method regardless of the size and position of the cavity. If a high-aspect ratio underground cavity with a depth of 2 m or more from the ground surface and an aspect ratio (a/b) of 2.0 or more is in the vertical direction, not only the factor of safety but the failure mode shape should be cautions in the stability evaluation using the shear strength reduction method. The results of this study are expected to be basic data on underground safety impact assessment.

한국에서 시행중인 특별법에 의한 지하안전영향 평가 수행 시, 필수적으로 지하공동의 발생 유무를 조사하여야 한다. 지하공동 발견 시에는 수치해석을 통해서 지하안전성을 평가하도록 규정하였다. 선행 연구를 통해서 소규모 지하공동의 2차원 형상변화를 통한 안전율 기반의 안정성 평가 가능성을 제시하였다. 본 연구에서는 3차원 형상을 고려하여 소규모 지하공동의 영향을 연속체 해석 프로그램을 사용해서 검토하였고, 선행 연구에서 제시한 2차원 해석결과와 비교하였다. 지하공동의 3차원 형상이 구(sphere)형에 가깝게 발견되면, 공동의 크기, 위치 등에 관계없이 전단강도감소기법으로 안전율을 산정하여 평가하는 방법에 무리가 없을 것으로 판단된다. 지표면으로부터의 깊이 2 m 이상, 장축과 단축의 비(a/b)가 2.0 이상인 장대형 지하공동이 연직방향으로 서있는 형상이라면, 전단강도감소기법을 사용한 안정성 평가에 안전율 이외에 파괴양상 파악에도 주의가 필요할 것으로 판단된다. 본 연구의 결과는 지하안전영향평가에 관한 기초 자료가 될 수 있을 것으로 판단된다.

Keywords

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