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针对中型拱坝下游消能防冲形式的选择问题,通过物理模型试验,对比分析了长护坦防护、水垫塘+二道坝和短护坦先冲后护3种布置形式下相应的水力学指标。试验结果表明:长护坦方案时,水垫塘内水流流态较差,底板和护岸易失稳破坏;水垫塘+二道坝方案时,水流流态和各项水力学指标满足要求,但造价较高;短护坦先冲后护方案时,冲坑位置及深度均在允许范围内,该方案的应用会受到拱坝下游地质条件的制约。依据短护坦先冲后护的试验成果,提出初步确定短护坦防护范围的方法。本工程下泄单宽流量较小,根据试验成果及类似工程经验,结合坝址地质和工程造价因素,推荐消能工布置方案为“短护坦先冲后护”方式。
According to the selection of energy dissipation and erosion-proofing forms in the downstream of medium-sized arch dams, the corresponding water under three kinds of layouts is analyzed through physical model test, such as long-tide protection, water cushion pond + Erdaoba and short- Mechanical indicators. The experimental results show that the water flow pattern in the pad pool is poor, and the bottom plate and bank protection are prone to failure. In the case of the cushion pad + Erda dam scheme, the water flow pattern and various hydraulic parameters meet the requirements. However, The cost is higher. When the short-arm tank is first washed and rear-protected, the position and depth of the red-pit are all within the allowable range. The application of this scheme will be restricted by the geological conditions in the downstream of the arch dam. Based on the test results of the short arm protection and the first test, the method of initially determining the protective range of short arm protection was proposed. According to the test results and similar engineering experiences, combined with the geology and engineering cost factors of dam site, the layout scheme of energy dissipater is recommended as “short protection tank first protection” mode.