受下游出口横向宽度有限等因素的影响，泄洪洞扩散式挑坎存在水舌入水面积过大、冲刷下游边坡的现象。本文针对这一现象，基于那棱格勒水利枢纽工程整体水工模型试验，对比研究扩散式挑坎和等宽式挑坎两种挑坎方案内部流态、水面线、流速、时均压力、出口水舌形态和下游冲刷情况等相关水力学特性。研究结果表明：等宽式挑坎内部横向水面变幅较小，发生空化的可能性较低，水舌入水宽度较小，消能效果充分。在改善挑坎流态，减轻下游岸坡冲刷起到重要作用，有效满足了当地实际地形对于入水水舌的要求和工程运行的需要。

Affected by the factor of the limited lateral width of the downstream outlets，the diffused flip bucket of the flood discharge tunnel has the phenomenon that the water entry area of the water jets is too large and the downstream slope is scoured． In view of this phenomenon，based on the overall hydraulic model test of the Nalenggele hydraulic project，two different flip buckets，namely，equal－width bucket and diffused bucket are put forward to analyze the internal flow pattern，water surface profile，flow velocity，time－average pressure，forms of water tongue and erosion situation of downstream channel of them． The results show that amplitude of the lateral water surface is small，the possibility of becoming cavitation is small，the water jet has a small width，and the energy dissipation effect is full． It plays an important role in improving the flow pattern of the bucket and reducing the scouring of the downstream bank slope，which effectively meets the actual local terrain and the needs of engineering operation．