溢流面板坝泄槽流激振动特性研究

Investigation on Flow-induced Vibration Characteristics of Overflow Concrete-faced Rockfill Dam Chute

针对溢流面板坝泄槽流激振动性能复杂的特征,基于ABAQUS建立了某溢流面板堆石坝的三维仿真模型,通过Matlab自编程序构造脉动压强时域激励荷载,采用时域分析法分析了不同流速条件流激振动作用下系统的模态和关键部位的应力应变情况。结果表明,在流激振动作用下,泄槽流速对溢流面板坝系统模态及泄槽底板接缝处的变形和关键部位的拉应力影响较大,特别是当流速大于40m/s时,系统基频下降速率较快,坝料弹模及泄槽板厚对系统基频影响较大,容易受水流激励影响诱发共振破坏,同时变形及拉应力明显增大,容易导致底板结构振动破坏,可通过提高坝料弹模及增大泄槽板厚来增强系统结构抵抗流激振动作用的稳定性。研究成果可为同类坝型泄流状态的安全评估及施工设计提供指导。

In view of complex flow-induced vibration performance of the overflow concrete face rockfill(CFRD)discharge chute,a 3Dsimulation model of the overflow concrete face rockfill dam was established based on ABAQUS.The pulsating pressure time domain excitation load was constructed by self-compiled program based Matlab.And then the mode of the system and the stress and strain condition of the key area in flow-induced vibration under different discharge conditions were analyzed by using the time domain analysis.The results show in flow-induced vibration,the flow rate of discharge chute was of great influence on the system mode of overflow concrete face rockfill dam,the deformation of commissure in chute bottom slab and pulling stress at the critical part;in particular,when the flow velocity was greater than40m/s,the system base frequency decreased faster,and the elastic modulus of dam filling materials and the thickness of the discharge board was of more influence on the system base frequency,and it is easy to be affected by the influence of hydraulic excitation and there by resonance damage was induced;at the same time,the deformation and pulling stress obviously increased,which can cause the vibration failure of the bottom board structure;the stability of the system structure against flow-induce d vibration could be enhanced by increasing elastic modulus of dam filling material and the thickness of the discharge plate.The research results can provide guidance for the safety assessment of discharge state and construction design of the same type dams.