Journal of Marine Sciences ›› 2012, Vol. 30 ›› Issue (3): 69-75.

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Numerical simulation of sea dikes breaching flood in the reclamation

XIE Chang fei1, SUN Zhi-lin1, Miao Bin2, XU Xue feng1,3   

  1. 1. Department of Ocean Science and Engineering, Zhejiang University, Hangzhou 310058, China;
    2. Mindong Marine Environment Monitoring Center, SOA, Ningde 352000, China;
    3. The Second Institute of Oceanography, SOA, Hangzhou 310012, China
  • Online:2012-09-15 Published:2022-11-30

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Abstract: Study on sea dikes breaching flood of the reclamation was carried out by means of numerical simulation in this thesis. The numerical model was based on the finite volume algorithm, which applied the HLI approximate Riemann solver to compute the numerical flux. A computational case study was presented of the flooding in a reclamation project of Zhejiang,where the flooded area and depth varying with time were obtained. The boundary condition of sea dikes breaching flow was taken by a constant water level, which is 20-year high tide level combined with the same frequency maximum wave height under the most unfavorable conditions. The model simulated the flooding in different locations of sea dikes failure successfully and the result shows that the submerged area and submerged depth rises quickly at the beginning of sea dikes breaching, and then the advance speed of flood tends to slow down,the average depth is followed by three stages of development: a slight decline, a dramatic rise and a small increase. The average depth for the south dike breaching flood is higher than that under the east dike-break case by 0.3~0.5 m at the same moment, so is the catastrophe and risk. The movement of flood caused by double breaching locations was further analysed. The flood spends only 60 minutes to overwhelm the reclamation, and the submerged depth rises to l.7 m after 4 hours. In the southeast, the convergence area between two sea dikes breaching flow, heavy personnel casualty will be caused, but the people in the rest area will have 15 minutes to escape the flood. In addition,the impact of roughness range from plus 15 per cent to minus 15 per cent on the flood was discussed. It is concluded that the differences between the maximum and minimum of average depth and submerged area reached 20 and 14 percent, respectively. This research will be of great practical significance to reduce the loss of sea dikes breaching accident as well as raise the management standard in the construction period and running period, which aims to provide the base of safety design and risk assessment of reclamation project.

Key words: reclamation, sea dikes breaching, flood, mathematical model