入流泥沙粒径组成对弱分层水体异重流及挟沙特性的影响

发布时间：2018-08-10 19:49

【摘要】：利用水槽设计水库分层水体模型试验,研究温度弱分层水体中不同入流泥沙粒径组成时异重流及其泥沙运动的特性。选用颗粒粒径0.01 mm、0.02 mm、0.05 mm的泥沙,开展了不同入流泥沙粒径组成条件下的异重流试验研究。在水温弱分层水库水体中,分析入流泥沙粒径组成的变化对分离点水深和间层流厚度的影响规律;不同泥沙粒径组成下,分析异重流在水库断面的泥沙浓度、较深的水域挟沙量变化规律;研究了泥沙沉淀量和悬浮量与入流泥沙粒径组成的关系。研究结果表明:在弱分层条件下,维持入流泥沙浓度3.75 g/L、入流速度0.005 m/s不变,异重流在水库中泥沙沉淀比例为29%~38%,泥沙在水库中的悬浮比例为46%~60%;粒径组成变化导致分离点深度和间层流厚度不同,颗粒粒径越大,分离点深度越深,间层流厚度越厚;异重流挟沙能力弱,水库淤积更严重,泥沙也会造成水库水浑浊;入库泥沙粒径越小,水库悬浮的泥沙浓度越大,水库的内源污染越大;当入库泥沙粒径较小时,宜在水库深水区取水,可减少水处理费用。研究成果可为水库取水、调水调沙提供参考。
[Abstract]:Based on the model test of stratified water in a reservoir designed by a flume, the characteristics of density flow and sediment movement under different particle size components of sediment in a weakly stratified water body with temperature are studied. Using the sediment with particle diameter of 0.01 mm or 0.02 mm to 0.05 mm, the experimental study on the density flow was carried out under the conditions of different particle size components of incoming sediment. In the water body of weakly stratified reservoir with water temperature, the influence of sediment particle size composition on water depth and interlaminar flow thickness at separation point is analyzed, and the sediment concentration of gravity current in reservoir section is analyzed under different sediment particle size composition. The relationship between sediment sedimentation amount and suspended amount and particle size composition of incoming sediment was studied. The results show that under the condition of weak stratification, the inlet sediment concentration is maintained at 3.75 g / L, and the inflow velocity is kept unchanged at 0.005 m / s. The sediment precipitation ratio of gravity current in reservoir is 29 / 38 and the suspended ratio of sediment in reservoir is 4660. The change of particle size composition leads to the difference of separation point depth and interlaminar flow thickness. The larger the particle size is, the deeper the separation point depth is and the thicker the interlaminar flow thickness is. The sediment concentration of the reservoir is smaller, the concentration of sediment suspended in the reservoir is larger, and the internal pollution of the reservoir is greater; when the sediment size is small, the sediment size of the reservoir is smaller. It is advisable to collect water in the deep water area of the reservoir and reduce the cost of water treatment. The research results can provide a reference for the reservoir to collect water and to transfer water and sediment.
【作者单位】：西安建筑科技大学环境与市政工程学院;
【基金】：国家自然科学基金面上项目(51278404) 陕西省科技统筹创新工程计划项目(2015KTCL03-15)
【分类号】：TV145

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