| 黄河中游支流悬移质粒度与含沙量、流量间的复杂关系 |
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| 引用本文： | 许炯心. 黄河中游支流悬移质粒度与含沙量、流量间的复杂关系[J]. 地理研究, 2003, 22(1): 39-48. DOI: 10.11821/yj2003010005 |
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| 作者姓名： | 许炯心 |
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| 作者单位： | 中国科学院地理科学与资源研究所, 北京 100101 |
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| 基金项目： | 国家自然科学基金资助项目 (40 2 710 19)，中国科学院地理科学与资源研究所知识创新工程领域前沿项目 (CXIOG -A0 0 - 0 5 - 0 1) |
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| 摘 要： | 本文以黄河中游若干支流为例,研究了宽变幅水沙两相流河流悬移质泥沙的粒度特征。结果表明,宽变幅水沙两相流河流的悬移质泥沙粒度特征与含沙量、流量之间具有复杂的关系。就同一站点而言,随着含沙量和流量的增大,大于0.05mm的粗颗粒泥沙的百分比迅速减小,并达到最小值;当含沙量和流量进一步增大时,其百分比又迅速增大,表现出明显的双值关系。对于小于0.01mm细泥沙而言,情形正好相反。黄河中游不同的支流之间,悬移质泥沙粒度特征与年均含沙量的关系也是复杂的。这些变化图形可以用非高含沙水流与高含沙水流不同的物理力学行为来解释
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| 关 键 词： | 悬移质泥沙 粒度特征 高含沙水流 黄河流域 |
| 文章编号： | 1000-0585(2003)01-0039-10 |
| 收稿时间： | 2002-07-08 |
| 修稿时间： | 2002-07-08 |
Complicated relationships between suspended sediment grain-size,water discharge and sediment concentration in tributaries of middle Yellow River |
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| XU Jiong-xin. Complicated relationships between suspended sediment grain-size,water discharge and sediment concentration in tributaries of middle Yellow River[J]. Geographical Research, 2003, 22(1): 39-48. DOI: 10.11821/yj2003010005 |
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| Authors: | XU Jiong-xin |
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| Affiliation: | Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China |
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| Abstract: | Based on the data from hydro-metric stations on the Yellow River and its tributaries, we have studied the grain-size characteristics of suspended sediment in relation to concentration and discharge. The middle Yellow River basin is located in a transitional zone from sub-humid to semi-arid climates, and covered by a thick loess mantle.In the neighboring desert areas in the northwest, the surface material of the Loess Plateau exhibits some remarkable areal differentiation in grain-size and forms three zones known as sandy!loess, (typical) loess and clayey loess from northwest to southeast. Controlled by these physico-geographical conditions, the grain-size of river sediment shows some particular characteristics. The plot of suspended sediment grain-size against water discharge and suspended concentration indicates some complicated variations. When the discharge or suspended concentration is low, the median size is relatively coarse. With an increase in discharge and concentration, the median size decreases to a minimum, and then increases again. During the low flow season, the relatively clear baseflow may scour the bed, so the suspended sediment is relatively coarse. Entering the rainy season, rainstorm runoff carrying fine loess material flashes to the river, making a decline in suspended sediment grain-size. However, during high-intensity rainstorms, hyperconcentrated flows often occur. Hyperconcentrated flows are a liquid-solid two-phase flow. The mixture of water and fine sediment is the liquid phase, and its unit weight is larger than clear water. The relatively coarse sediment particles suspended in the liquid phase constitute the solid phase. Hence, with the increase in concentration, more coarse particles can be set in suspension, and the median size increases again.For rivers located in different zones of surface material, some complicated relations between suspended load grainsize and mean annual suspended concentration has also been found. Double-value relations between grain-size and concentration exists, which can also be explained by the specific physico-geographical settings and the behaviors of hyperconcentrated flows in this area. |
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| Keywords: | suspended sediment grain-size hyperconcentrated flow Yellow River |
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