Journal of the Korean Geosynthetics Society (한국지반신소재학회논문집)

Korean Geosynthetics Society (한국지반신소재학회)
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A Study on the Open Cut Restoration of Underground Cavity Using Concrete Mat

콘크리트매트를 이용한 개착식 지반공동 복구방법에 관한 연구

  • Park, Jeong-Jun (Incheon Disaster Prevention Research Center, Incheon National University) ;
  • Shin, Heesoo (Institute of Technology Research and Development, UCI Tech co. Ltd.) ;
  • Chung, Yoonseok (Korea Conformity Laboratories) ;
  • You, Seung-Kyong (Dept. of Civil Engineering, Myongji College) ;
  • Hong, Gigwon (Institute of Technology Research and Development, Korea Engineering & Construction)
  • Received : 2018.12.11
  • Accepted : 2019.03.16
  • Published : 2019.03.30
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Abstract

This paper describes results of experimental and numerical analyses, in order to analyze a reinforcement effect of concrete mat on open cut restoration of underground cavity. The plate loading tests were conducted to evaluate a reinforcement effect of concrete mat, at reinforcement depths from the ground surface of 10 cm, 20 cm, and 30 cm. The result showed that the reduction ratio of stress (earth pressure) was about 60% at all reinforcement depth. The reinforcement effect considering ground surface settlement and reduction ratio of stress based on laboratory tests and numerical analysis was significant, at reinforcement depths from the ground surface of 10 cm~20 cm. LFWD test results showed that subgrade modulus was the largest when concrete mat was installed 20 cm below ground surface. Therefore, it is effective to reinforce concrete mat within 20 cm from the surface, when the underground cavity due to damage of underground utilities was formed in the height direction to the bottom of the pavement layer.

본 연구에서는 최근 발생빈도가 증가하고 있는 지반함몰의 가장 큰 영향요소인 지중 공동에 대하여 콘크리트매트를 이용한 개착식 복구방법의 보강효과 분석을 위한 실험적 및 수치해석적 연구를 수행하였다. 먼저, 평판재하시험을 이용하여 지표로부터 10cm, 20cm, 30cm의 보강깊이에 대하여 콘크리트매트 보강에 따른 응력감소율을 평가한 결과, 약 60%의 응력감소 효과를 나타내었다. 또한 실내실험과 수치해석 결과를 이용하여 지반침하량과 응력감소율을 분석한 결과, 콘크리트매트 설치깊이가 지표로부터 10cm~20cm 깊이에서 보강효과가 우수한 것으로 확인되었다. 지반변형계수 측정을 위한 LFWD실험 결과, 콘크리트매트가 지표로부터 20cm의 깊이에 보강되었을 때의 변형계수가 가장 크게 나타났다. 따라서 지중 매설물 손상에 의한 지중공동이 포장체 하부까지 높이 방향으로 발달한 경우, 지표로부터 20cm 이내에 콘크리트 매트를 보강하는 것이 효과적인 것으로 분석되었다.

Keywords

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Fig. 1. Underground cavity restoration and reinforcement principle using concrete mat

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Fig. 2. Procedure of laboratory test using Concrete mat (Continued)

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Fig. 3. Results of earth pressure increment due to loading

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Fig. 4. Reduction ratio of earth pressure according to reinforced depth of Concrete mat

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Fig. 5. Numerical analysis verification model

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Fig. 6. Numerical analysis model verification by comparing laboratory test and numerical analysis

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Fig. 7. Numerical analysis results of earth pressure increment due to loading

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Fig. 8. Reinforcement effect of Concrete mat by laboratory test and numerical analysis

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Fig. 9. Procedure of LFWD test

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Fig. 10. Results of LFWD test

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Fig. 2. Procedure of laboratory test using Concrete mat

Table 1. Physical properties of soil

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Table 2. Materials property

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