泄洪洞是水利水电工程中重要的泄水建筑物，在我国许多大中型水利水电工程中得到了广泛应用。泄洪洞具有水头高、泄流流量大、水流流速高以及流态复杂等特点，在运行期间极易遭受到破坏。因此，基于泄洪洞流场水力特性，对泄洪洞运行期间不同特征水位工况下所遭受到的破坏进行分析研究，有利于在泄洪洞设计阶段、施工阶段、运行阶段、管理等阶段中对症下药，对泄洪洞内易受破坏的部位进行优化和保护，提高水利工程安全可靠程度，降低日常维护检修成本，为泄洪洞的设计和保护研究提供相关参考依据，具有重大的科学研究意义。本文紧密结合紫坪铺水利枢纽工程实际，采用标准 双方程模型，利用几何重构格式的VOF法追踪自由水面，对紫坪铺1#、2#泄洪洞流场水力特性进行了三维数值模拟，构建了适用于泄洪洞高速水流的三维数学模型，获得了包括泄洪能力、水流流态及水面线、掺气坎空腔长度、底板及边壁压强、流速、水流空化数等泄洪洞水力要素。将数值计算结果与水工模型试验结果进行对比，结果表明计算结果与试验结果较为接近，从而验证了高水头泄洪洞水流数学模型的适用性与可靠性。采用SST-DDES紊流模型对紫坪铺1#泄洪洞2#掺气坎水流脉动压强进行了数值模拟，并对水流脉动压强信号进行时域、频域特性分析。结果表明，泄洪洞水流属于低频水流范畴，振动频率主要分布在0至20HZ范围内，优势主频约为0.12。各测点脉动压强值近似服从正态分布，脉动压强波动变化范围在-3至3倍的脉动压强均方根之间，并受相邻瞬时值的影响较大。泄洪洞掺气坎后沿程水流脉动压强服从单峰分布。数值模拟结果与水工模型试验结果在变化趋势上相似，但受掺气、高流速等因素影响，脉动压强变化曲线在幅值与相位上，模拟值与试验值存在一定差距。基于高水头泄洪洞流场水力特性，对泄洪洞运行期常遇的空化空蚀、泥沙颗粒冲刷磨蚀、洞顶余幅、水流振动等破坏问题进行分析研究。根据泄洪洞的破坏特点，结合运行期原型实测壁面破坏资料，对泄洪洞破坏危险区域进行划分，并提出了泄洪洞设计及保护建议。

Spillway tunnels are important drainage structures in water resources and Hydropower projects. They have been widely used in many large and medium-sized water resources and hydropower projects in china.They have the characteristics of high water head,large discharge flow,high velocity and complicated flow pattern,and are extremely vulnerable during operation.Therefore,combined with the hydraulic characteristics of the high head spillway tunnels,the damage under different working conditions during the operation of spillway tunnels have been studied.It is beneficial to optimize and protect the vulnerable parts in the spillway tunnels,improve the safety and reliability of the projects,reduce the daily maintenance and repire cost during the design, construction, operation and management stages of the spillway tunnels.The study is of great significance to provide reference for the design and protection of spillway tunnels. In this parer, based on the actual situation of Zipingpu water conservancy project,the flow fields of No.1 and No.2 spillway tunnels were solved by 3D numerical simulation which adopted the standard k-ε two-equation model and used the VOF method of geometric reconstruction format to track the free water surface.The 3D mathematical model of the flow in spillway tunnels were established.The flow field data of spillway tunnels were obtained,including the discharge capacity, flow regime and water suface line,the length of the aerator cavities,the pressure of the bottom and side walls,velocity and cavitation number.The numerical simulation results were in good agreement with the hydraulic model test results, which verified the applicability and reliability of the mathematical model of the spillway tunnels.The SST-DDES turbulence model was used to simulate the fluctuation pressure of flow in NO.2 aerator in NO.1 spillway tunnel.The fluctuation pressure signals were analyzed of time domain and frequency domain characteristics. The results showed that the water flow in the flood discharge tunnel belonged to the category of low frequency water flow.The vibration frequency of flow was mainly distributed in the range of 0~20HZ and the dominant frequency was about 0.12. The fluctuating pressure values of each measuring point obeyed normal distribution and range from -3 to 3 times the RMS of the fluctuating pressure.The fluctuation pressure of aerators in spillway tunnels obeyed the single-peak distribution and were greatly influenced by the adjacent instantaneous values. The numerical simulation results were similar to the hydraulic model test results in changing trend. However, dued to aeration, high flow rate and other factors, there were differences in amplitude and phase between simulated and experimental values of fluctuating pressure.Based on the hydraulic characteristics of the flow field in a high head spillway tunnel, the problems of cavitation, erosion, residual amplitude at the top of tunnels and flow vibration, which are often encountered during the operation of the spillway tunnel were studied and analyzed. According to the damage characteristics of spillway tunnels and the field prototype test data during operation period, the dangerous areas of spillway tunnels were divided and suggestions for design and protection of spillway tunnels were put forward.