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Anchorage mechanism of inflatable steel pipe rockbolt depending on rock stiffness

팽창형 강관 록볼트의 암반 강성에 따른 정착 거동 특성

  • 김경철 (다산컨설턴트 지반터널부) ;
  • 김호종 (건국대학교 공과대학 인프라시스템공학과) ;
  • 정영훈 (건국대학교 공과대학 인프라시스템공학과) ;
  • 신종호 (건국대학교 공과대학 인프라시스템공학과)
  • Received : 2017.03.14
  • Accepted : 2017.03.27
  • Published : 2017.03.31

Abstract

The expansion behavior of inflatable steel pipe rockbolt shows geometric nonlinearity due to its ${\Omega}-shaped$ section. Previous studies on the anchoring behavior of inflatable steel pipe rockbolt were mainly performed using theoretical method. However, those studies oversimplified the actual behavior by assuming isotropic expansion of inflatable steel pipe rockbolt. In this study, the anchoring behavior of the inflatable steel pipe rockbolt were investigated by the numerical method considering the irregularity of pipe expansion and other influencing factors. The expansion of inflatable steel pipe rockbolt, the contact stress distribution and the change of the average contact stress and the contact area during installation were analyzed. The contact stresses were developed differently depending on the constitutive behavior of rocks. Small contact stresses occurred in steel pipes installed in elasto-plastic rock compared to steel pipes installed in elastic rock. Also, the anchoring behaviors of the inflatable steel pipe rockbolt were different according to the stiffness of the rock. The steel pipe was completely unfolded in the case of the stiffness smaller than 0.5 GPa, but it was not fully unfolded in the case of the stiffness larger than 0.5 GPa for the given analysis condition. When the steel pipe is completely unfolded, the contact stress increases as the rock stiffness increases. However, the contact stress decreases as the rock stiffness increases when the steel pipe is not fully expanded.

Acknowledgement

Grant : 고수압 초장대 해저터널 기술자립을 위한 핵심요소 기술개발

Supported by : 건설교통과학기술진흥원, National Research Foundation of Korea

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