Journal of the Korean Geosynthetics Society (한국지반신소재학회논문집)

Korean Geosynthetics Society (한국지반신소재학회)
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An Experimental Study on Ground Reinforcement Effect of Concrete and Expansion Mat for Prevention of Buried Pipe Damage

지중매설관 손상 방지를 위한 콘크리트매트와 팽창매트의 지반보강효과에 관한 실험적 연구

  • Park, Jeong-Jun (Incheon Disaster Prevention Research Center, Incheon National University) ;
  • Shin, Heesoo (Institute of Technology Research and Development, UCI Tech co. Ltd.) ;
  • Yuu, Jungjo (GoldenPow Co.) ;
  • Hong, Gigwon (Institute of Technology Research and Development, Korea Engineering & Construction)
  • Received : 2019.01.15
  • Accepted : 2019.03.25
  • Published : 2019.03.30
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Abstract

Recently, small-scale excavation like ground cavity restoration and buried pipe replacement works are being carried out in urban area, in order to improve living convenience. This paper describes experiment results on the ground reinforcement method that can reduce the buried pipe damage, when the differential settlement occurred due to poor compaction of ground below the buried pipe. Plate load tests were conducted to evaluate a reinforcement effect of ground using concrete mat and expansion mat in the ground below the buried pipe. The results showed that the stress reduction ratio by concrete mat and expansion mat according to the surcharge load was about 46%~48% and 39%~42%, respectively. Therefore, the differential settlement of the buried pipe and the ground deformation below the buried pipes were reduced by the reinforcement effect of the concrete mat and expansion mat. This means that it is possible to prevent a buried pipe damage due to underground cavity and ground subsidence, if concrete mat and expansion mat are reinforced in the ground below the buried pipe or on the ground between the buried pipes.

최근 도심지내에서는 지반공동 복구공사, 관로교체 공사 등 생활의 편의성 확보를 위한 소규모 굴착공사가 이루어지고 있다. 본 연구에서는 지중매설관 하부의 미흡한 다짐관리로 인하여 부등침하가 발생할 경우, 관의 파손에 의한 피해를 저감하기 위해 관 하부를 보강할 수 있는 방안에 대하여 실험적 연구를 수행하였다. 즉, 콘크리트매트와 팽창매트를 이용한 매설관 주변지반의 보강효과에 관한 평판재하시험을 실시하였다. 실험결과, 콘크리트매트와 팽창매트 보강에 따른 지중응력 감소율은 재하하중 크기에 따라 각각 약 46%~48% 및 39%~42%로 분석되었다. 즉, 콘크리트매트와 팽창매트의 지반보강효과에 기인하여, 연구에 적용된 각각의 재료는 매설관의 침하 및 매설관 하부지반의 변형을 감소시키는 효과가 있는 것으로 판단되었다. 이를 바탕으로 지중매설관 하부지반 또는 매설관 사이의 지반에 콘크리트매트 및 팽창매트를 보강한다면, 지중에서 예측하기 어려운 공동발생 및 지반침하에 따른 매설관 손상을 다소 방지할 수 있는 것으로 평가되었다.

Keywords

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Fig. 1. Reinforcement principle for prevention of buried pipe damage based on concrete mat and expansion mat

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Fig. 2. Materials for reinforcement on bottom of life line (Park et al., 2018)

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Fig. 3. Overview of laboratory test

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Fig. 4. Procedure of laboratory test using concrete mat and expansion mat

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Fig. 5. Strain of buried pipe according to concrete mat reinforcement

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Fig. 6. Load variation according to ground depth

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Fig. 7. Reduction ratio of earth pressure according to concrete mat reinforcement

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Fig. 8. Strain of upper buried pipe according to expansion mat reinforcement

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Fig. 9. Strain of lower buried pipe according to expansion mat reinforcement

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Fig. 10. Load variation according to ground depth

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Fig. 11. Reduction ratio of earth pressure according to expansion mat reinforcement

Table 1. Engineering properties of soil

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Table 2. Case of laboratory test

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