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An investigation on the ground collapse mechanism induced by cracks in a non-pressurized buried pipe through model tests

모형시험을 통한 비압력 지중관거 균열로 인한 지반함몰 메커니즘 연구

  • Kim, Yong-Key (Civil Engineering Team, Doosan Engineering & Construction) ;
  • Nam, Kyu-Tae (Dept. of Civil Engineering, Konkuk University) ;
  • Kim, Ho-Jong (Dept. of Civil Engineering, Konkuk University) ;
  • Shin, Jong-Ho (Dept. of Civil Engineering, Konkuk University)
  • 김용기 (두산건설(주) 토목환경BG 설계팀) ;
  • 남규태 (건국대학교 인프라시스템공학과) ;
  • 김호종 (건국대학교 토목공학과) ;
  • 신종호 (건국대학교 인프라시스템공학과)
  • Received : 2018.01.02
  • Accepted : 2018.02.13
  • Published : 2018.03.31

Abstract

Groundwater flow induced by cracks in a buried pipe causes ground loss in the vicinity of it which can lead to underground cavities and sinkhole problems. In this study, the ground collapse mechanism and the failure mode based on an aperture in the pipe located in cohesionless ground were investigated through a series of physical model studies. As the influence parameters, size of the crack, flow velocity in the pipe, groundwater level, ground cover depth and ground composition were adopted in order to examine how each of the parameters affected the behavior of the ground collapse. Influence of every experimental condition was evaluated by the final shape of ground failure (failure mode) and the amount of ground loss. According to the results, the failure mode appeared to be a 'Y' shape which featured a discontinuous change of the angle of erosion when a groundwater level was equal to the height of the ground depth. While in the case of a water table getting higher than the level of ground cover depth, the shape of the failure mode turned to be a 'V' shape that had a constant erosion angle. As the height of the ground depth increased, it was revealed that a mechanism where a vertically collapsed area which consisted of a width proportional to the ground height and a constant length occurred was repeated.

Acknowledgement

Supported by : National Research Foundation of Korea

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