| 摘要: |
| 选用长江口北槽黏性细颗粒泥沙，在不同盐度的人工海水中通过静水沉降、动水沉降等各种试验手段了解其基本特性。在静水沉降管中观测了胶粒的电化学絮凝过程和重力碰并过程，于不同盐度条件下找出最佳絮凝盐度；并通过黏性细颗粒泥沙在流动海水中絮凝的试验研究，揭示其在动水中絮凝的机理和规律，及不同条件下的起动流速、不淤流速、沉降速度等特征值，从而分析其落淤情况。研究结果表明，长江口北槽细颗粒黏性泥沙的最佳絮凝盐度约为15，起动流速为15～20 cm/s，这与泥沙的淤积固结时间有关，而不淤流速约为60 cm/s。并由试验得到了挟沙力与流速之间的经验关系，以及用于估算不同流速条件下泥沙沉降速度及淤积量的经验公式。这些结果可用于长江口航道的疏浚、整治工作中，具有一定的理论指导意义。 |
| 关键词: 长江口北槽 细颗粒泥沙 絮凝 沉速 盐度 |
| DOI： |
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| 基金项目:国家863计划资助项目(2006AA09Z157) |
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| Experimental study on characteristics of cohesive sediment in North Passage of the Yangtze River (Changjiang) estuary |
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YANG Yang,PANG Chong-guang,JIN Ying,ZHOU Jing-jing
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| Abstract: |
| This paper has selected cohesive fine grain sediment in North Passage of the Yangtze River (Changjiang) estuary. Some experiments have been done under different salinity conditions to understand their basic characteristics. And the best flocculation salinity can be found. Through the experimental study of flocculation of cohesive fine grain sediment in North Passage of the Yangtze River (Changjiang) estuary mechanism and laws in the moving water were revealed, and start up velocity, the critical deposit velocity, and settling velocity were obtained in order to analyze its deposition. The three main conclusions can be presented: ⅰ) The optimal salinity is about 15. ⅱ) The threshold velocity is between 15～20 cm/s, and it is associated with consolidation deposition time. ⅲ) The critical deposit velocity is 60 cm/s. By the experiment the relationship between the sediment carrying capacity and velocity can be obtained as well as the empirical formula which was used to estimate the sediment settling velocity and deposit volume. |
| Key words: North Passage of the Yangtze River (Changjiang) estuary fine sediment flocculation settling velocity salinity |
