三峡水库淤积泥沙物理特性初步研究

发布时间：2018-07-02 07:41

本文选题：大水深 + 干密度　；参考：《长江科学院》2017年硕士论文

【摘要】：三峡水库库区泥沙淤积分布的总体特征表现为不连续的宽谷和弯道淤积,峡谷河段基本无累积性淤积;库区淤积物中粘土矿物的比例增大,意味着三峡水库发生水体富营养化的潜在风险增大。水库淤积物干密度受众多因素影响,且关系到水库淤积的准确计算。本文在对三峡水库特征断面(点)进行淤积物物理特性取样分析的基础上,围绕着水库淤积干密度变化影响研究,探讨了水库原位取样的可行性方案,设计了一套可长期观测大水深条件下淤沙干密度变化的模拟实验装备并开展了系列室内实验。实验设置了7种水压条件,对三峡库区坝前、皇华城等淤沙样品的干密度变化进行了模拟实验。本文取得如下成果:(1)通过对水库沿程各断面连续4次高/低库水位条件下现场淤沙取样,分析了淤沙矿物质组成特性;(2)开展了水库淤沙干密度变化规律的室内模拟实验,实验结果表明:淤积物的密实速率在2d内发展很快,之后进入平稳的慢速密实过程。当水深超过150m时,淤沙的密实过程及干密度变化相对较快;水压仅对初期的低浓度密实过程有显著影响,对高浓度及干密度变化稳定后的低浓度样品的密实过程影响不大。样品的配比浓度和样品粒径对干密度初期变化率有显著影响。(3)比较论证了现有原位干密度取样器取样的特点、难点及不足,提出了新的研发思路并就“自重作用下旋转进占取样”方案进行了可行性分析。本文研究可为大型水库的淤积分析及计算提供参考。
[Abstract]:The overall characteristics of sediment deposition distribution in the reservoir area of three Gorges Reservoir are discontinuous wide valley and curved channel siltation, and there is basically no accumulative siltation in the canyon reach, and the proportion of clay minerals in the silt in the reservoir area increases. This means that the potential risk of eutrophication in the three Gorges Reservoir will increase. The dry density of reservoir silt is affected by many factors, and it is related to the accurate calculation of reservoir siltation. On the basis of sampling and analyzing the physical characteristics of sediment in the characteristic section of the three Gorges Reservoir, the feasibility scheme of in-situ sampling of the reservoir is discussed on the basis of the study on the influence of the dry density variation of the reservoir deposition. A set of simulative experimental equipment for long-term observation of dry density of silt under the condition of large water depth was designed and a series of laboratory experiments were carried out. Seven kinds of water pressure conditions were set up to simulate the dry density change of silt samples in front of the dam in the three Gorges Reservoir area. In this paper, the following results are achieved: (1) the characteristics of sediment mineral composition are analyzed through four successive sampling of silt on each section along the reservoir under the condition of high / low reservoir water level, and (2) the indoor simulation experiment of the variation law of silt dry density of reservoir is carried out. The experimental results show that the compaction rate of the silt develops rapidly within 2 days and then enters into a steady slow compacting process. When the water depth is more than 150 m, the densification process and dry density of silt change relatively quickly, and the water pressure only has a significant effect on the initial low concentration compaction process, but has little effect on the densification process of the low concentration sample after the change of high concentration and dry density is stable. The sample concentration and particle size have a significant effect on the initial change rate of dry density. (3) the characteristics, difficulties and shortcomings of the existing in situ dry density sampler are compared. A new idea of research and development is put forward and the feasibility of the scheme of rotating sampling under the action of self-weight is analyzed. This study can be used as a reference for siltation analysis and calculation of large reservoirs.
【学位授予单位】：长江科学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV145

【相似文献】