弧形闸门闸坝一体化静动力分析及安全评价

针对弧形闸门安全评价中采用的闸门单体计算模型过于简化的问题,应用有限元软件ANSYS对比分析了惯用的闸门单体结构模型与考虑止水摩阻及支铰和牛腿间直接作用的闸坝一体化模型在全闭和瞬间开启2种工况下的静动力特性。以闸坝一体化模型为准,在静力分析方面,在全闭工况时单体模型下框架主横梁的最大位移及等效应力分别偏大108.5%和67.1%,支臂内力偏大52.8%,单体模型下框架极不经济;在瞬间开启工况时单体模型上框架主横梁的最大位移及等效应力偏差分别为-10.1%和-21.2%,支臂内力偏小8.1%,单体模型上框架极不安全。在动力分析方面,止水及流固耦合作用使闸坝一体化模型的弧门前10阶频率最大下降48%,远离了流激振动的主频区,利于弧门的动力稳定。结果表明:合理弧形闸门结构安全评价的模型应为校核水位瞬间开启工况下的闸坝一体化模型,采用此工况及模型才能确保结构分析的正确性,实现闸门结构安全性与经济性的统一。

Static and Dynamic Analysis and Safety Assessment of Radial Gate Based on Gate-Dam System

In view of the excessive simplification of single gate calculation model in safety assessment of radial gate, we compared and analyzed the static and dynamic characteristics between conventional single gate model and gate-dam system model considering friction of seal and the direct action between hinge and bracket under fully closed condition and instantaneously opening condition. Gate-dam system model was taken as standard. In static analysis, the maximum displacement and equivalent stress of main beam of lower frame for single gate model under fully closed condition are 108.5% and 67.1% larger, respectively. And internal force of arm is 52.8% larger. As a result, the lower frame of single gate model is very uneconomical. The maximum displacement and equivalent stress of main beam of upper frame for single gate model under instantaneously opening condition are 10.1% and 21.2% smaller, respectively. And the internal force of arm is 8.1% smaller. Therefore the upper frame of single gate model is very insecure. Moreover in dynamic analysis, the first ten natural frequencies of gate-dam system decreases 48% maximally with peripheral sealing and fluid-structure interaction, dodging the dominant frequency region of vibration excited by flow. It is beneficial to the dynamic stability of radial gate. Results show that reasonable model for safety assessment of radial gate should be gate-dam system model at check water level under instantaneously opening condition, which could ensure the validity of structural analysis and coordinate between safety and economy of gate structure.