本文選題：三峽庫區(qū) + 彎道　； 參考：《重慶交通大學(xué)》2014年碩士論文

【摘要】：長江三峽工程是全世界矚目的特大型水利水電樞紐工程，其建成后庫區(qū)由河道轉(zhuǎn)為水庫，庫區(qū)水位提升、水流減緩，水體自凈能力也有所下降，，部分支流河段已經(jīng)出現(xiàn)了富營養(yǎng)化現(xiàn)象。富營養(yǎng)化問題除與水流狀態(tài)有關(guān)外，其水體氮、磷含量與泥沙狀況是其最主要的影響因素，而由于三峽庫區(qū)水文情況的變化，彎道段泥沙的淤積情況更為嚴(yán)重。因此進(jìn)行三峽庫區(qū)重慶典型彎道段泥沙與氮、磷污染物的關(guān)系研究對防治長江流域的水體富營養(yǎng)化具有重要的理論意義與現(xiàn)實價值。 本文在分析三峽庫區(qū)重慶段主要斷面多年水沙監(jiān)測數(shù)據(jù)的基礎(chǔ)上，采用理論分析、現(xiàn)場監(jiān)測和室內(nèi)實驗相結(jié)合的方法對三峽庫區(qū)重慶典型彎道段泥沙與氮、磷污染物關(guān)系進(jìn)行了研究，獲得的主要研究結(jié)果如下：三峽庫區(qū)重慶段輸沙量和泥沙的淤積往往集中在汛期，且彎道段泥沙的淤積情況更為嚴(yán)重，同時汛期庫區(qū)重慶段存在氮、磷污染；三峽庫區(qū)重慶典型彎道段—皇華城水域的水中泥沙以細(xì)顆粒泥沙為主，其中D≤0.025mm的泥沙以重量計占總重的72%~90%；泥沙含量是決定天然水體氮、磷含量的一個主要因素。該區(qū)域泥沙對天然水體磷含量的貢獻(xiàn)率為56.2%~64.4%；泥沙對天然水體總氮含量的貢獻(xiàn)率為62.1%~68.7%，對氨氮含量的貢獻(xiàn)率為54%~67%，對硝態(tài)氮的貢獻(xiàn)率為51%~78%。室內(nèi)機理試驗中得知，小粒徑的泥沙相對于較大粒徑泥沙對氮、磷污染物的吸附量大；泥沙吸附氮、磷的吸附量隨泥沙濃度增大而增加，吸附量隨污染物濃度增加而增大；酸堿性對泥沙吸附氮、磷污染物有影響，pH在3～11變化時，泥沙對氮磷的吸附量基本上均呈“U”型變化，泥沙對氮磷的吸附量在pH為7時均最小；當(dāng)振蕩速率為120r/min～720r/min時，吸附量為0.11mg/g～0.18mg/g，隨振蕩速率增大而增加，泥沙對磷的吸附量與振蕩速率有較好的正相關(guān)性；泥沙對磷的解吸量隨泥沙粒徑的增大而減小，且0h～11h為主要解吸時段，11h～48h為極慢速解吸時段，11h時，泥沙濃度為0.2kg/m3～1.5kg/m3時，磷的解吸量為0.213mg/g～0.277mg/g，說明泥沙對磷的解吸量是隨著泥沙濃度的增加而減小。 本文研究可以為三峽庫區(qū)水體氮、磷污染防治與長江水資源保護(hù)提供重要的科學(xué)依據(jù)。
[Abstract]:The three Gorges Project of the Yangtze River is an extremely large water conservancy and hydropower hub project that has attracted worldwide attention. After its completion, the reservoir area has changed from a river to a reservoir. The water level in the reservoir area has risen, the water flow has slowed down, and the self-purification capacity of the water has Eutrophication has occurred in some tributaries. The eutrophication problem is not only related to the flow state, but also the nitrogen, phosphorus content and sediment condition are the most important influencing factors. Because of the change of the hydrological situation in the three Gorges Reservoir area, the sediment deposition in the bend section is more serious. Therefore, it is of great theoretical and practical value to study the relationship between sediment and nitrogen and phosphorus pollutants in typical bend sections of the three Gorges Reservoir area in order to prevent eutrophication in the Yangtze River basin. On the basis of analyzing the monitoring data of water and sediment in the main sections of Chongqing section of the three Gorges Reservoir area, the paper uses the method of theoretical analysis, field monitoring and laboratory experiment to study the sediment and nitrogen in typical bend section of Chongqing reservoir area. The main results obtained are as follows: sediment transport and sediment deposition in Chongqing section of the three Gorges Reservoir area are usually concentrated in flood season, and the sediment deposition in bend section is more serious, and nitrogen exists in Chongqing section of reservoir area during flood season. Phosphorus pollution; sediment in water of typical bend section of Chongqing-Huanghua city in the three Gorges Reservoir area is dominated by fine grain sediment, in which D 鈮

本文編號：1854285