锚索索力损失对预应力闸墩动态特性的影响

某水电站泄洪闸采用大吨位预应力闸墩承受弧形闸门支臂传递的巨大水推力,通过近2 年的闸墩锚索拉力监测发现,锚索张拉力损失部分超过15%,并尚未收敛,且闸墩在宣泄洪水过程中曾出现过强烈振动现象.为进一步明确锚索拉力损失是否对闸墩动态特性(包括模态特性、动位移与动应力特性)产生影响,建立了闸墩-基础-锚索整体有限元模型,通过制作闸墩水力学模型并采用力传感器测量作用于闸墩上的整体面荷载,获取不同运行工况下的闸墩整体水动力荷载时程线,以此为有限元模型输入荷载进行闸墩动态响应计算,分析了泄洪闸预应力闸墩主、次锚索不同索力损失对闸墩的动态特性的影响,研究成果可为工程安全运行提供重要参考.

Influence of anchor cable force loss on prestressedpier dynamic characteristics

Large-tonnage prestressed pier of a hydropower station is applied to resist huge hydraulic thrust from theradial gate arms. Pier cable tension monitoring in nearly two years shows that part of the anchor tensile force hadlost by more than 15% and not converged, and that the pier had strong vibration during the flood discharge. Inorder to clarify the influence of the anchor cable force losses on dynamic characteristics of the pier(including modalcharacteristic, dynamic displacement and dynamic stresses), a finite element overall model of pier-foundation-anchor is established, and the pier hydraulic model measuring the overall surface loads acting on the pier surface isset up to obtain the overall hydrodynamic loads under different operating conditions. Then, the overall surface loadsare taken as the input loads for calculation of pier dynamic response, and analysis of the influence of primary andsecondary anchor cable force losses on the pier dynamic characteristics is made. Those research results can providean important reference for the safe operation of the same projects.