墩头超长实用堰泄洪安全分析及模型试验验证——以缅甸DAPEIN(Ⅰ)水电站工程为例
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摘要
以缅甸DAPEIN(Ⅰ)水电站工程为例,论述了将WES实用堰的闸墩墩头向上游超长延伸之后,对泄洪安全所造成的影响。针对WES实用堰流量系数、堰面动水压力容易受边界因子影响的特点,对设计断面的堰顶布置和墩头形状进行了优化。根据堰面空化数计算公式及水流特性推导出计算的关键部位,对空化数进行计算。采用几何比尺为1∶60的物理模型对溢流堰的泄流能力和堰面动水压力进行了试验测试。试验结果表明:溢流堰的模型试验泄流能力和设计泄流能力非常相近。堰面动水压力除工况2的B4测点出现了-1.2 k Pa的微小负压值外,其余堰面时均压强值均大于0。从而,在泄流能力和堰面动水压力两方面都验证了这种设计方案的合理性。该工程所遇到的结构布置问题在中低溢流坝工程中属常见问题,解决思路可为今后类似工程建设借鉴参考。
By taking DAPEIN( I) Hydropower Station in Burma as a study case,the impact from the super-long extension of the gate pier head of the WES weir to the upstream direction on the safety of flood discharge is discussed herein. For the characteristics of the WES weir that the flow coefficient and surface hydrodynamic pressure are prone to be affected by the boundary factors,the layout on the weir crest and the shape of the pier head of the design section are optimized. In accordance with the calculation formula of the weir surface cavitation number and flow characteristics,the key locations to be calculated are deduced,so as to make a pertinent calculation on the cavitation number. Meanwhile,the discharge capacity and the surface hydrodynamic pressure of the overflow weir are tested by the physical model with the scale of 1 ∶ 60. The test result shows that the discharge capacity of the overflow weir from the model test is quite close to that from the design. Except the occurrence of a slight negative pressure of-1. 2 k Pa of the weir surface hydrodynamic pressure at the measuring point B4 of the operation condition 2,all the values of the weir surface time-average pressure are larger than 0. Thereby,the reasonability of the design is verified in both the aspects of the discharge capacity and the weir surface hydrodynamic pressure. The problem of the structure layout encountered in the project is a common problem in the projects of medium-low overflow dam,and then the solution idea mentioned herein can provide a reference for the similar projects in the days to come.
By taking DAPEIN( I) Hydropower Station in Burma as a study case,the impact from the super-long extension of the gate pier head of the WES weir to the upstream direction on the safety of flood discharge is discussed herein. For the characteristics of the WES weir that the flow coefficient and surface hydrodynamic pressure are prone to be affected by the boundary factors,the layout on the weir crest and the shape of the pier head of the design section are optimized. In accordance with the calculation formula of the weir surface cavitation number and flow characteristics,the key locations to be calculated are deduced,so as to make a pertinent calculation on the cavitation number. Meanwhile,the discharge capacity and the surface hydrodynamic pressure of the overflow weir are tested by the physical model with the scale of 1 ∶ 60. The test result shows that the discharge capacity of the overflow weir from the model test is quite close to that from the design. Except the occurrence of a slight negative pressure of-1. 2 k Pa of the weir surface hydrodynamic pressure at the measuring point B4 of the operation condition 2,all the values of the weir surface time-average pressure are larger than 0. Thereby,the reasonability of the design is verified in both the aspects of the discharge capacity and the weir surface hydrodynamic pressure. The problem of the structure layout encountered in the project is a common problem in the projects of medium-low overflow dam,and then the solution idea mentioned herein can provide a reference for the similar projects in the days to come.
引文
[1]刘志明,温续余.水工设计手册(第7卷)泄水与过坝建筑物(第2版)[M].北京:中国水利水电出版社,2014.
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[4]姜伯乐,杨文俊,张晖.三峡工程表孔空化问题试验研究与原型验证[J].水力发电学报,2009,28(6):71-74.
[5]董丽丽,孙亚东.团山子水利枢纽溢流坝水工模型试验研究[J].吉林水利,2013(2):21-23.
[6]AZIMI H,HADAD H,SHOKATI Z,et al.Discharge and flow field of the circular channel along the side weir[J].Canadian journal of civil engineering,2014,42(4):273-280.
[7]HUANG B,GU S.Design of small,hard-shell overflow dams on compressible foundations[J].Journal of energy engineering,1998,124(1):20-32.
[8]BAGHERI S,HEIDARPOUR M.Overflow characteristics of circular-crested weirs[J].Journal of hydraulic research,2010,48(4):515-520.
[9]秦根泉,陆晶.DAPEIN(I)水电工程大坝冲砂底孔体型试验[J].湖北水力发电,2009(3):27-29.
[10]周建平,党林才.水工设计手册(第5卷)混凝土坝(第2版)[M].北京:中国水利水电出版社,2011.
[11]中华人民共和国水利部.混凝土重力坝设计规范:SL 319—2005[S].北京:中国水利水电出版社,2005.
[12]李炜.水力计算手册(第2版)[M].北京:中国水利水电出版社,2006.
[13]张绍芳.实用堰侧收缩影响系数的计算[J].水文,1994(4):22-26.
[14]中华人民共和国水利部.溢洪道设计规范:SL 253—2000[S].北京:中国水利水电出版社,2000.
[15]武汉大学水资源与水电工程科学国家重点实验室.缅甸DAPEIN(I)水电站工程首部枢纽水工、泥沙及导流整体模型试验研究报告[R].武汉:武汉大学水资源与水电工程科学国家重点实验,2008.
[2]陈巧威.溢流堰的体型与行洪能力[J].水利科技,2008(4):46-48.
[3]李静,李丹,姜伯乐.带闸墩溢流坝控泄工况二维与三维数值模拟[J].水利水电科技进展,2011,31(6):10-13.
[4]姜伯乐,杨文俊,张晖.三峡工程表孔空化问题试验研究与原型验证[J].水力发电学报,2009,28(6):71-74.
[5]董丽丽,孙亚东.团山子水利枢纽溢流坝水工模型试验研究[J].吉林水利,2013(2):21-23.
[6]AZIMI H,HADAD H,SHOKATI Z,et al.Discharge and flow field of the circular channel along the side weir[J].Canadian journal of civil engineering,2014,42(4):273-280.
[7]HUANG B,GU S.Design of small,hard-shell overflow dams on compressible foundations[J].Journal of energy engineering,1998,124(1):20-32.
[8]BAGHERI S,HEIDARPOUR M.Overflow characteristics of circular-crested weirs[J].Journal of hydraulic research,2010,48(4):515-520.
[9]秦根泉,陆晶.DAPEIN(I)水电工程大坝冲砂底孔体型试验[J].湖北水力发电,2009(3):27-29.
[10]周建平,党林才.水工设计手册(第5卷)混凝土坝(第2版)[M].北京:中国水利水电出版社,2011.
[11]中华人民共和国水利部.混凝土重力坝设计规范:SL 319—2005[S].北京:中国水利水电出版社,2005.
[12]李炜.水力计算手册(第2版)[M].北京:中国水利水电出版社,2006.
[13]张绍芳.实用堰侧收缩影响系数的计算[J].水文,1994(4):22-26.
[14]中华人民共和国水利部.溢洪道设计规范:SL 253—2000[S].北京:中国水利水电出版社,2000.
[15]武汉大学水资源与水电工程科学国家重点实验室.缅甸DAPEIN(I)水电站工程首部枢纽水工、泥沙及导流整体模型试验研究报告[R].武汉:武汉大学水资源与水电工程科学国家重点实验,2008.