近期长江口南港河槽沉积地貌变异及其可能原因

发布时间：2018-04-27 03:06

本文选题：长江口 + 南港　；参考：《长江流域资源与环境》2016年04期

【摘要】：南港是长江口两个主要入海通道之一,也是长江深水航道的必经之路。基于2012和1984年的地形资料,利用Arc GIS技术对南港进行冲淤分析;并用同一种方法(筛析法-移液管)对相应年份所采表层沉积物样品进行粒径测试对比。结果表明:近28年来南港地形发生了重大变化,复式河槽间的沙脊因刷深而趋于消亡,主航槽则淤浅数米;沉积物中值粒径均值从81μm下降为24μm,特别是原沙脊位置上的沉积物从砂变细为砂质粉砂或粘土质粉砂。分析认为,采砂是上述变化的主要原因:沙脊采砂使复式河槽"中脊"消失,水动力减弱,河槽中央过水断面增大、分流增多,两侧航槽流速减小导致淤浅;沉积物变细是较粗颗粒被采走、动力减弱和淤积发生的综合结果。
[Abstract]:Nangang is one of the two main channels into the Yangtze River Estuary, and is also the only way for the Yangtze River deep channel. Based on the topographic data of 2012 and 1984, the scour and deposition analysis of Nangang was carried out by Arc GIS technique, and the particle size of surface sediment samples collected in corresponding years were measured and compared by the same method (sieve analysis method-pipette). The results show that the topography of Nangang has changed greatly in the past 28 years. The sand ridges between the composite channels tend to die out because of the depth of scouring, while the main channels are silt for a few meters. The mean value of median grain size of sediment decreased from 81 渭 m to 24 渭 m, especially the sediment on the original sand ridge became fine from sand to sandy silt or clay silt. It is concluded that sand mining is the main reason for the above changes: sand excavation on the ridge of sand causes the disappearance of the "middle ridge" of the double-channel, the weakening of the hydrodynamic force, the increase of the cross section in the middle of the channel, the increase of the distribution, and the decrease of the velocity of the channel on both sides, which results in shallow siltation; Sediment thinning is the combined result of coarse particles being mined, dynamic weakening and silting.
【作者单位】：华东师范大学河口海岸学国家重点实验室;浙江省水利河口研究院;南京大学海岸与海岛开发教育部重点实验室;
【基金】：上海市科委项目(10dz210505) 国家自然科学基金重点项目(41130856)~~
【分类号】：TV148

【相似文献】