Estimation of Retained Rate in Open-water Sediment Disposal

Hosung Shin; Kyu-Sun Kim

doi:10.7843/kgs.2015.31.11.49

All Issue

2015 Vol.31, Issue 11 Preview Page

Estimation of Retained Rate in Open-water Sediment Disposal 개방수역 퇴적물 처리에서 유보율의 평가

30 November 2015. pp. 49-60

PDF XML

Abstract

Open-water sediment disposal has many applications in costal construction. Dumping of sediment in open water can be divided into descending stage under water and sedimentation stage on the seabed, and retained rate is evaluated from analyzed results of these two successive stages. Descending particle cloud have two distinct thermal and swam phase, and trajectory equations for each phase are derived to describe settling velocity and radius of particle cloud. For sedimentation stage, a numerical simulator is used to calculate growth factors for particle fiction angle and current velocity. Retained rate is defined as a mass rate of remained sediment inside the circle which has a center at dumping point on the sea level and user-defined effective radius. Retained rate map for Singapore coast is presented with water depth of 20 m, current velocity of 0.0～1.5 m/s, and effective radius of 5 m. It will decrease sediment mass loss during disposal operation and minimize surrounding environmental pollution.

Keywords

Open-water sediment disposal

Particle cloud

Sedimentation

Retained rate

개방수역 퇴적물 처리는 해안공사에서 다양한 목적으로 수행되고 있다. 매립토의 거동은 수중 침강단계와 하상 퇴적단계로 구분하여 해석을 수행하였으며, 이를 이용하여 매립토의 수중 투기에 의한 유보율을 평가하였다. 매립토 입자의 침강단계는 thermal 단계와 swarm 단계로 구분하여 입자구름의 침강속도와 환산 반경에 대한 일반화된 방정식을 제시하였다. 하상 퇴적단계는 개발된 프로그램을 이용하여 매립토의 마찰각과 유속의 변화에 따른 퇴적형상의 성장계수를 평가하였다. 유보율은 매립토의 해수면 위의 투기지점을 원의 중심으로 하고 원의 유효 반경내에 잔류하는 매립토의 질량비로 정의하였다. 싱가포르 현장을 기준으로 수심을 20m, 유속은 0.0-1.5m/s 구간에서 유효반경 5m에 대한 유보율도를 제시하였다. 이는 해안 매립공사에서 매립토의 유실율을 저감하여 시공성을 개선하고 주변환경오염을 최소화하는 자료로 활용될 수 있다.

References

1.Bhuiyan, F., Rajaratnam, N., and Zhu, D.Z. (2010), “An Experimental Study of Mounds Formed by Dumping Coarse Sediment in Channel Flow”, Journal of Hydraulic Research, Vol.48, No.3, pp.283-291.

2.Bühler, J. and Papantoniou, D.A. (1991), “Swarms of Coarse Particles Falling through a Fluid”, In: Lee, J.H.W., Cheung, H.Y. (Eds.), Environmental Hydraulics. Balkema, Rotterdam, pp.135-140.

2.Bush, J.W.M., Thurber, B.A., and Blanchette, F. (2003), “Particle Clouds in Homogeneous and Stratified Environments”, J. Fluid Mech., Vol.489, pp.29-54.

3.Gensheimer, R.J. (2008), Dynamics of Particle Clouds in Ambient Currents with Application to Open-water Sediment Disposal, Massa-chusetts Institute of Technology, Cambridge, MA, p.259.

4.Gensheimer, R.J., Adams, E.E., and Law, A.W.K. (2013), “Dynamics of Particle Clouds in Ambient Currents with Application to Open Water Sediment Disposal”, J. Hydraul Eng., ASCE, Vol.139, No.2, pp.114-123.

5.Gu, J., Huang, J., and Li, C.W. (2008), “Experimental Study on Instantaneous Discharge of Unsorted Particle Cloud in Cross-flow”, Journal of Hydrodynamics, Vol.20, No.1, pp.10-16.

6.Hallworth, M.A., Hogg, A.J., and Huppert, H.E. (1998), “Effects of External Flow on Compositional and Particle Gravity Currents”, J. Fluid Mech., Vol.359, pp.109-142.

7.Montgomery, R.L. and Engler, R.M. (1986), “Fate of Dredged Material during Openwater Disposal”, Environmental Effects of Dredging Technical Notes, Technical Report EEDP-01-2, U.S. Army Engineer Waterways Experiment Station, Vicksburg.

8.Noh, Y. (2000), “Sedimentation of a Particle Cloud Across a Density Interface”, Fluid Dyn. Res., Vol.27, pp.129-142.

9.Noh, Y. and Fernando, H.J.S. (1993), “The Transition in the Sedimen-tation Pattern of a Particle Cloud”, Phys. Fluids A, Vol.5, pp.3049-3055.

9.Rahimipour, H. and Wilkinson, D. (1992), “Dynamic Behavior of Particle Clouds”, Proc. 11th Australasian Fluid Mechanics Conf. University of Tasmania, Hobart, Australia, pp.743-746.

10.Ruggaber, G.J. (2000), The dynamics of particle clouds related to open-water sediment disposal, PhD thesis, Massachusetts Institute of Technology, Cambridge, MA, p.241.

11.Shin, H. (2014), “FEM Numerical Formulation for Debris Flow”, Journal of the Korean Geotechnical Society, Vol.30, No.10, pp.55-65.

12.Soo, S.L. (1990), Multiphase Fluid Dynamics, Butterworth-Heinemann, p.696.

13.Tropea, C., Yarin, A.L., and Foss, J.F. (2007), Handbook of Experi-mental Fluid Mechanics, p.557.

14.Zhao, B., Law, A.W.K., Adams, E.E., and Er. J.W. (2014), “Formation of Particle Clouds”, Journal of Fluid Mechanics, Vol.746, pp. 193-213.

Information

Publisher :The Korean Geotechnical Society
Publisher(Ko) :한국지반공학회
Journal Title :Journal of the Korean Geotechnical Society
Journal Title(Ko) :한국지반공학회 논문집
Volume : 31
No :11
Pages :49-60
Received Date : 2015-11-23
Revised Date : 2015-11-23
Accepted Date : 2015-11-23
DOI :https://doi.org/10.7843/kgs.2015.31.11.49

Journal of the Korean Geotechnical Society ISSN:1229-2427(Print) 2288-646X(Online) 한국지반공학회 논문집

All Issue