【作者】 邢日县；

【导师】 樊贵盛；

【作者基本信息】 太原理工大学 ， 水利水电工程， 2012， 硕士

【摘要】 在我国,尤其在北方地区水资源严重短缺,地下水超采已成为北方地区的共性问题。地下水限量开采也已成为地下水资源保护的主要措施。因此,为了满足人类日常生活及社会发展的用水需求,近几年来,我国北方地区傍河取水工程与日俱增。在实际开采河槽地下潜水工程建设中遇到的技术问题是理论计算结果与实际工程取水量相差过大。现场的详细踏勘分析认为,这与河床堆积砂卵石层中存在的漂石有直接的关系。本文对河床漂石-砂卵石介质渗透特性展开研究,对于傍河取用地下水工程建设以及提高取水效率有重大的意义。本文以柳林黄河滩地原状自然堆积砂卵石及其漂石为研究对象,运用试验研究的方法,从漂石形状、尺度、级配、剖面结构、淤积层等对砂卵石的渗透系数和渗流通量的影响方面,进行了系统研究。取得了以下几点主要结论：(1)天然河床漂石--砂卵石介质的粒径特征对渗透系数的影响很大。粒径特征不同,砂卵石介质其孔隙的数量与大小、渗透水流的过水面积以及细颗粒的充填度不同,渗透系数随砂卵石粒径特征的变化而发生变化。砂卵石介质的渗透系数与砂卵石有效粒径d10、限制粒径d60和不均匀系数Cu均具有密切的相关关系。渗透系数K随着d10的增大而增大,随着d60的增大而增大,随着Cu的增大而减小。渗透系数与有效粒径d,。和限制粒径d60均呈二次函数相关关系,与不均匀系数Cu呈对数相关关系。砂卵石介质的渗透系数及水力梯度与漂石的截面面积及体积之间亦具有高度的相关性。(2)当河道水深不变,淤泥含量较小时,大部分淤泥将通过砂卵石介质孔隙通道被水流带出,淤泥对渗流通量的影响因而不明显。但是,当淤泥层厚度增加到一定程度之后,砂卵石介质部分孔隙将被累积增加的淤泥堵塞,此时,渗流通量将逐渐减小。在等厚度淤积层的覆盖下,河床中砂卵石的渗流通量随着河道水深的增大而增大。但是,在砂卵石表面淤积层厚度较大的情况下,随着试验的进行,河道水深的增大对砂卵石渗流通量的影响逐渐减弱。(3)在大粒径卵石覆盖层及细颗粒介质与土工布复合覆盖层下对砂卵石的阻泥保渗效果较好,细颗粒介质与土工布复合覆盖层最佳阻泥保渗效果组合结构为：土工布+细颗粒+土工布。在综合考虑砂砾石介质的渗透系数和水质状况的情况下,得出人工渗床最佳砂砾石剖面结构从上到下依次是：14cm厚1～0.25mmm细颗粒+土工布+20cm厚3～1m1n砂砾石+20cm厚6-3mm砂砾石+20cm厚10～6mm砂砾石+20cm厚30-1Omm砂砾石+20cm厚50～30mm砂砾石+15cm厚90-50mm砂砾石。本文对不同粒径配比砂砾石介质人工渗床剖面结构的研究,只是根据试验结构进行初步分析,最终得出的最佳剖面结构需要日后的工程实践验证。更多还原

【Abstract】 The serious short of water resources in our country, especially in the northern regions, the groundwater overdraft has become the common problems of the northern regions. The limited exploitation of groundwater has also become the main measures for protection of groundwater resources. Therefore, in recent years, the water intake project near the river has gradually increase in the northern china in order to meet the water demand of human daily life and social development. The technological problem is the large difference between theoretical calculated result and practical engineering water intake quantity in the exploitation riverbed underground water project construction actually. It was considered through the detailed reconnaissance in the field analysis that it have a direct relationship with boulder of accumulation sand pebble layer in the river trough. The paper researches permeability characteristics of the boulder and sandy gravel media the river trough, which possesses important significance for taking underground water project construction near the river and improving water intake efficiency.Taking the original state natural accumulation sandy pebble and boulders at Liulin County Yellow River bottomland as the research object, using the method of experimental study, from the aspect of the influence of boulders shape, scale, gradation, profile structure, sediment deposit to osmotic coefficient and osmotic flus of sandy pebble carrying out systematically study. The following main conclusions were drawn: (1) The characteristic diameter index of boulder and sandy gravel media on natural riverbed contributed significantly to the permeability coefficient. The characteristic diameter indexes are different, and the numbers and size of pore space of sandy gravel media, the discharge area of seepage flow and the percentage filling of fine particle are different too, that is characteristic diameter indexes have influences on the permeability coefficient. There are the close correlation among permeability coefficient of sandy gravel media and its effective diameter (d10), limit diameter (d60) and Non-uniform coefficient (Cu). The permeability coefficient (K) increases with the increase of the d10, the same as with the increase of the d60, while the permeability coefficient decreases with the increase of the Cu, there is a logarithmic relationship between permeability and Non-uniform coefficient (Cu), while a quadratic equation can be fitted to the correlation between permeability coefficient and effective diameter (d10) the same as with Non-uniform (Cu). There are the close correlation among permeability coefficient of sandy gravel media and the size of boulder and hydraulic gradient.(2)When the depth of water in the river course is kept constant and the content of sullage occurs in small amounts, a majority of sullage will be taken away by water through pore way in the cobblestone medium. Therefore, the effect of sullage on the seepage flux is less visible. But when the depth of sullage increases to certain extent, a part pore of cobblestone medium will be jammed by the increasing sullage. And at the same time, seepage flux decreases gradually. Covered by the sullage with the same depth, the seepage flux of cobblestone in the river course increases with the increase of water depth. But in the context of lager depth of sullage on the surface of cobblestone, alone with the progress of the experiment, the influence of the increasing depth of water on the seepage flux is weaken little by little.(3)The coating which consists by large size cobble, fine particle and geotextile has the best mud resist and keep infiltrating function. The best composite structure of fine particle and geotextile compound coating which to resist mud and keep seepage is geotextile+fine particle+geotextile. After overall consideration to osmotic coefficient and water quality, the top to bottom best sand gravel profile structure of artificial percolating filter is1～0.25mm pine particle14cm+geotextile+3～1mm sand gravel20cm+6～3mm sand gravel20cm+10～ 6mm sand gravel20cm+30～10mm sand gravel20cm+50～30mm sand gravel20cm+90～50mm sand gravel15cm.The research on artificial percolating filter profile structure of different particle size matching sandy gravel media in this paper,which only belongs to preliminary analysis according to the test structure, the best profile structure eventually got need the future project practice verification.更多还原