Erodibility of cohesive sediments along the Nigerian transgressive mud coast: A preliminary experimental study
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摘要: 河口和沿海地区由于陆地和海洋的相互联系而具有重要的生态和经济意义. 各种自然和人为事件影响着这些地区的地貌不平衡, 因此研究泥沙输移动态有助于海岸带的可持续管理. 本文研究了尼日利亚西南部大西洋沿岸海侵泥质海岸海相粘土的一些基本物理和矿物性质. 结果表明, 该区粘土矿物以高岭石和伊利石为主. 沉积物的水分和有机质含量较高, 说明了微生物的作用和生物活性. 它们具有相对较低的液限(< 60%)、塑性指数(< 15%)和粘土不活性(> 0.5). 尽管沉积物通常是低塑性的有机粉土/粘土, 但伊洛托罗泥浆倾向于中塑性到高塑性的有机粘土. 此外, 沉积物中有机质与粘土含量之间存在正相关关系, 它们支持沉积物化学对其物理性质的影响, 从而影响沉积物的可蚀性. 需要进行进一步的研究, 以确定沉积物的力学性质, 并生成一个沉积物输运模型, 用于准确预测淤泥质海岸沉积物的侵蚀阈值. 这项研究的结果将适用于世界各地具有类似沉积物特性的海岸带, 以满足环境、工程和公共卫生的需要.
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Key words:
- estuaries /
- mud coast /
- erodibility /
- cohesive sediments
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Fig. 2 (A) Classification chart of the clays (modified from Casagrande, 1948), (B) Relationship between clay and organic content
Note: CL = Inorganic clays of low to medium plasticity; OL = Organic silts and organic silt-clays of low plasticity; ML = Inorganic silts, very fine sands, silty or clayey fine sands, of low plasticity; OH = Organic clays of medium to high plasticity; CH = Inorganic clays of high plasticity; MH = Inorganic silts of high plasticity
Tab. 1 Basic physical and mineralogical properties of the sediments
LOCATION Moisture
content/%Organic
content/%pH sand/% silt/% clay/% Liquid
Limit/%Plastic
Limit/%Plasticity
Index/%Activity
(PI/Clay fraction)Dominant
clay mineralGbabijo 60.1 11.6 7.39 10.1 50.5 39.4 39.9 32.6 7.3 0.19 Kaolinite Ayetoro 58.5 14.3 7.2 13.1 44.8 32.1 54.1 40.7 13.4 0.42 Illite Ilowo 68.7 14.8 7.14 10.2 68.1 21.3 43.2 37.9 5.8 0.27 Kaolinite -
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