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基于环境流体动力学模型(Environment Fluid Dynamic Code/EFDC)水动力和泥沙模块,该文针对九龙江口-厦门湾水域潮动力强、浅滩面积大的特点建立二维潮流泥沙数学模型并利用实测数据进行校验。模型精简适用,成功反演了该水域的水动力场和悬沙浓度场,并能正确反映浅水区域的水沙运动特征。结果表明:在潮流作用下,厦门湾水体中悬沙浓度由外向内递增,悬沙随着潮流的涨落在湾内外作中-长距离的往复运动。湾内特别是浅滩区,大潮期悬沙浓度大于小潮期且浓度随潮变化明显,小潮期悬沙场则较为稳定。采用抓斗式挖泥船(源强Q=7.5 t/h)在翔安东南侧浅滩疏浚作业对邻近保护区基本无影响,但翔安南部“五岔口”型潮汐汊道存在能远程输运近岸疏浚泥沙的“泥泵式”水动力场,促使形成环绕厦门岛东海域的带状悬沙分布,该文进一步揭示了形成该分布的水动力机制。增大疏浚强度可导致白海豚保护区被污染,悬沙带宽度增大,浓度上升。
Based on the Hydrodynamic and Sediment Module of the Environment Fluid Dynamic Code (EFDC), a two-dimensional tidal current sediment mathematical model is established for the characteristics of strong tidal instability and large shoal area in the Jiulongjiang Estuary-Xiamen Bay waters. Data verification. The model is concise and applicable, successfully retrieving the hydrodynamic field and suspended sediment concentration field of this water area, and correctly reflecting the characteristics of water and sediment movement in shallow water areas. The results show that under the action of tidal current, the concentration of suspended sediment in Xiamen Bay water increases from the outside to the inside, and the suspended sediment moves in the long distance between the inside and outside of the bay as the tidal current fluctuates. Especially in shoals, the concentration of suspended sediment in the tidal period is larger than that in the tidal period and the concentration changes obviously with the tide, and the sediment flushing area in the tidal period is relatively stable. The use of a grab dredger (source strength Q = 7.5 t / h) had no effect on the adjacent nature reserve in the dredging operations on the southeastern side of the Xiang An area. However, there was a long-distance The “mud-pump” hydrodynamic field that transported the dredged sediment from the coast drove the formation of zonal suspended sediment around the east coast of Xiamen Island. This paper further reveals the hydrodynamic mechanism that forms this distribution. Increasing the dredging intensity can lead to the pollution of the dolphin reserve, the increase of the width of the suspended sediment and the increase of the concentration.