All Issue

2018 Vol.34, Issue 10 Preview Page
October 2018. pp. 51-60
Recently, a cylindrical cut-off wall was proposed as a new technology for temporary offshore works. The cut-off wall has a cylindrical shape, so seepage analyses are necessary to analyze the effect of wall shape. In this study, a numerical analysis was performed to investigate the seepage discharge inside cut-off walls. The numerical modeling was verified by comparing with the theoretical solution for the cofferdam with double sheet piles. Two different flow conditions were compared between 2-dimensional flow and axisymmetric flow. The results showed that the discharge of the axisymmetric flow was about 1.55 times larger than that of 2-dimensional plain flow. A parametric study was carried out by varying wall radius, penetration depth of the wall, and total head difference between in and outside of the wall. The discharge decreased with the increase of the penetration depth and the wall radius. Finally, the design equations were suggested to determine the discharge for the preliminary design of the cylindrical cut-off wall.
최근 해상 작업을 위한 새로운 시공기술로서 대형원형강재 가물막이 공법이 제안되었다. 본 구조물은 원형 형상의 가물막이이기 때문에 가물막이의 형상에 따른 침투해석 연구가 필요하다. 그러므로, 본 연구에서는 흐름해석을 수행하여 원형 가물막이에 대하여 벽체 내부로의 침투 유량을 산정하였다. 흐름해석에 이용된 수치모델링은 2열의 널말뚝을 가진 가물막이에 대하여 제안된 이론해와 비교하여 검증하였다. 흐름조건의 경우 축대칭 흐름조건의 침투유량이 2차원 흐름조건의 침투유량과 비교하여 1.55배 크게 나타났으므로 2차원 축대칭 흐름조건을 적용하였다. 벽체 반경, 벽체의 지중 근입깊이 그리고 벽체 내외부의 수위차 등을 변화시키며 변수연구를 수행한 결과, 침투유량은 벽체의 근입깊이와 벽체 반경이 증가할수록 감소하는 것으로 나타났다. 최종적으로, 대형원형강재 가물막이의 침투유량을 산정할 수 있는 간이식을 제안하였다.
  1. Craig, R. F. (2004), Craig's soil mechanics, Taylor and Francis, New York, pp.83-88.
  2. Darcy, H. (1856), Les fontaines publiques de la ville de Dijon: exposition et application... Victor Dalmont.
  3. Graham, J., Pinkney, R.B., Lew, K.V., and Trainor, P.G.S. (1982), "Curve-fitting and Laboratory Data", Canadian Geotechnical Journal Vol.19, pp.201-205.10.1139/t82-023
  4. López, N. P., Sánchez, M. A., Auvinet, G., and Pereira, J. M. (2014), "Assessment of Exit Hydraulic Gradients at the Toe of Levees in Water Drawdown Conditions", Proc. of the 7th International Conference on Scour and Erosion, Perth, Australia, pp.171-181. CRC Press.10.1201/b17703-21
  5. Ojha, C. S. P., Singh, V. P., and Adrian, D. D. (2003), "Determination of Critical Head in Soil Piping", Journal of Hydraulic Engineering, Vol.129, No.7, pp.511-518.10.1061/(ASCE)0733-9429(2003)129:7(511)
  6. Sedghi, A. M., Rahimi, H., and Khaleghi, H. (2010), "Experimental Analysis of Seepage Flow under Coastal Dikes", Experimental Techniques, Vol.34, No.4, pp.49-54.10.1111/j.1747-1567.2009.00562.x
  7. Simulia (2012), ABAQUS user's manual, version 6.12.
  8. Tanaka, T., Hayashi, K., and Yamada, M. (2000), "Seepage Failure of Soil in an Axisymmetric Condition", Proc. of the Geotech-Year 2000, Asian institute of technology, Bangkok, Thailand, pp.665-674.
  9. Vicent, S., Tran, V.A., and Kim, S.R. (2017), "Numerical Investigation on Seepage Stability in Offshore Bucket Cut-off Walls", Journal of the Korean Geotechnical Society, Vol.33, No.11, pp. 73-82.
  10. Yousefi, M., Sedghi-Asl, M., and Parvizi, M. (2016), "Seepage and Boiling around a Sheet Pile under Different Experimental Configuration", Journal of Hydrologic Engineering, Vol.21, No.12, 06016015.10.1061/(ASCE)HE.1943-5584.0001449
  • Publisher :The Korean Geotechnical Society
  • Publisher(Ko) :한국지반공학회
  • Journal Title :Journal of the Korean Geotechnical Society
  • Journal Title(Ko) :한국지반공학회 논문집
  • Volume : 34
  • No :10
  • Pages :51-60
  • Received Date :2018. 09. 13
  • Accepted Date : 2018. 10. 15