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本文回顾了以往薄拱坝泄洪布置形式,阐述了提高坝身泄洪能力的途径,并引用模型试验测得的坝下冲刷区河床上动水压力和冲刷变化资料,分析了冲击消能的基本原理和消能效果,从而提出:(1)高拱坝采用表、中(深)孔水舌竖向冲击的消能方式,能明显提高消能效果,但必须注意对表、中孔体型、尺寸和水力指标的选择;(2)采用表、中孔分别单独运行的泄洪布置,需按表孔和中孔单独泄洪时的下游河床最大动力荷载设计防护工程,势必使工程费用增加,而不能发挥冲击消能的效益;(3)如必须考虑表、中(深)孔单独运行,则可表、中孔错开布置,避开表、中孔两层水舌交汇冲击;(4)当隧洞泄洪能抬高坝下水位时,宜按启用隧洞泄洪时总泄量的相应下游水位设计坝下的防护工程;(5)对具有足够的下游水深,河床又有一定抗冲能力的情况,坝的消能防护措施,可以考虑护坡不护底,这样既可节省防护工程量,又可减少防护检修工作。
This paper reviews the layout of the flood discharge layout of the thin arch dam in the past, expounds the ways to improve the flood discharge capacity of the dam body, and uses the data of hydrodynamic pressure and scour on the riverbed in the scouring area under the model test, and analyzes the basic principles of impact energy dissipation (1) The energy dissipating mode of vertical arch impact on the high arch dams using the middle and deep hole water tongues can obviously improve the energy dissipation effect. However, it is necessary to pay attention to the energy dissipation of the table, mesopore type, size And hydraulic indexes; (2) The flood discharge arrangement using single-hole and single-hole respectively should be designed according to the maximum dynamic load of the downstream river bed when the single hole and the single hole are separately discharged, which will inevitably increase the cost of the project and will not be able to play Impact energy dissipation; (3) If you have to consider the table, the (deep) hole run alone, you can table, staggered layout in the hole to avoid the table, the two holes in the water hole intersection impact; (4) When the water level under the dam can be raised, the protection works under the dam should be designed according to the corresponding downstream water level of the total discharge when the flood discharge tunnel is started; (5) For the dam with sufficient downstream water depth and a certain impact resistance in the riverbed, Energy-saving protective measures, you can consider the slope does not protect the bottom, which The same can save the amount of protection projects, but also reduce the protective maintenance work.