潮汐河口淹没丁坝群坝田淤积特征及成因分析
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摘要
潮汐河口淹没丁坝群坝田水动力条件复杂多变,坝田复杂的水流结构决定了坝田内的泥沙淤积过程及淤积形态。以长江口北槽丁坝群形成坝田为例,分析坝田形成后淤积形态及淤积速率特征和规律。分析结果表明:随着时间推移,坝田内2 m等深线逐渐向距坝头0. 2倍坝长处靠近,5 m等深线逐渐向坝头处靠近;坝田的初始容积与冲淤平衡时的平衡容积呈对数关系;在丁坝间距为3～4倍坝长时,坝田内淤积分布最为均衡;坝田内淤积速率的拐点均出现在坝田形成后5～6 a。另外,从工程影响淤积丁坝布置参数方面探讨坝田内淤积特征的成因。
The hydrodynamic conditions of the dam group flooded by the tidal estuaries are complex and changeable,and the complicated flow structure of the spur dikes field determines the siltation process and the form of siltation in the field. Taking the field formed by the spur dikes at the north passage of the Yangtze estuary for example,we analyze the deposition pattern, rate characteristic and regularity of the dam field after the dam formation.The result reveals that with the passage of time,the dam within 2 m isobath gradually closes to 0. 2 times the distance from the dam head dam strengths,and 5 m isobath gradually closes to the dam at the head of the dam;there appears a logarithmic relationship between the initial volume of the dam field and balance volume at the scour sedimentation equilibrium; when the groin spacing is 3 to 4 times the length of dam,dam deposition distributes in equilibrium; the inflection point appears 5-6 years after the dam formation. Moreover, the causes of the siltation characteristics in the dike field are discussed in terms of the layout parameters affecting the silt dam.
The hydrodynamic conditions of the dam group flooded by the tidal estuaries are complex and changeable,and the complicated flow structure of the spur dikes field determines the siltation process and the form of siltation in the field. Taking the field formed by the spur dikes at the north passage of the Yangtze estuary for example,we analyze the deposition pattern, rate characteristic and regularity of the dam field after the dam formation.The result reveals that with the passage of time,the dam within 2 m isobath gradually closes to 0. 2 times the distance from the dam head dam strengths,and 5 m isobath gradually closes to the dam at the head of the dam;there appears a logarithmic relationship between the initial volume of the dam field and balance volume at the scour sedimentation equilibrium; when the groin spacing is 3 to 4 times the length of dam,dam deposition distributes in equilibrium; the inflection point appears 5-6 years after the dam formation. Moreover, the causes of the siltation characteristics in the dike field are discussed in terms of the layout parameters affecting the silt dam.
引文
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[2]吴小明,谢宇峰.水工建筑物下游回流及底沙淤积研究[J].人民珠江,1996(6):16-19.
[3]许光祥,程昌华.丁坝挑角对坝田淤积的影响[J].水运工程,1994(8):94-98.
[4]赵渭军.涌潮作用下丁坝近区淤积观测与试验研究[D].杭州:浙江大学,2009.
[5]刘猛,李为华.长江口北槽深水航道回淤量变化宏观动力原因分析[J].水运工程,2013(3):129-139.
[6]于守兵.淹没丁坝对水流结构的调整作用研究[D].南京:南京水利科学研究院,2010.
[7]陈国祥,张锦琦,陈耀庭.淹没丁坝雍水规律试验研究[J].河海大学学报,1991,19(5):88-93.
[8]应强,孔祥柏.淹没丁坝群雍水试验研究[J].水利水运科学研究,1995(1):13-21.
[9]张国安,虞志英,何青,等.长江口深水航道治理一期工程前后泥沙运动特性初步分析[J].泥沙研究,2003(6):31-38.
[10]周海,张华,阮伟.长江口深水航道治理一期工程实施前后北槽最大浑浊带分布及对北槽淤积的影响[J].泥沙研究,2005(5):58-65.
[11]窦希萍.长江口深水航道治理工程一、二期工程泥沙回淤预报研究[C]中国海洋工程学会.第十二届中国海岸工程学术讨论会论文集.南京:中国海洋工程学会,2005.
[12]刘杰,徐志杨,赵德招,等.长江口深水航道(一、二期工程)回淤变化[J].泥沙研究,2009(2):22-28.