水电站机墩结构自振特性研究

水电站机墩组合结构是水轮发电机组的主要支撑结构,其自振特性是分析共振复核和动态设计的重要基础.<水电站厂房设计规范>中的自振频率计算公式过于简化,不完全符合实际.以某大型水电站地厂房为例,对其机墩组合结构建立三维有限元计算分析模型,比较了机墩各种不同组合模型的自振频率及振型.结果表明,仅仅模拟机墩结构或只考虑机墩及其上部或下部结构,都不能准确反映机墩结构的真实性态,也将对振动安全评价产生不利影响.从理论上讲,考虑一定范围围岩的整体有限元模型最符合实际,也较为科学,但从方便实用的角度分析,考虑机墩组合的整体混凝土结构较为适宜.

Study on self-vibration characteristics of foundation structure of hydropower station

The turbine foundation composite structure of powerhouse in hydropower station is main supporting system of generating unit,self-vibration characteristics are important basis of resonance check and dynamic design.According to ＂the design criterion of hydro powerhouse＂,the self-vibration frequency of turbine foundation is too simplified with the actual.Taking some underground powerhouse for example,a three-dimensional model of the turbine foundation composite structure is created,and the self-vibration frequency and strikeout of different composite models is compared.The results indicated that neither simulate turbine foundation only nor includes its adjacent structures is accurate in reflecting the authenticity of the structures.At the same time,it would be unfavorable effects on safety evaluation.The whole finite element model,which considering the limits of certain surrounding rock is actually and scientific in theory.But it is more appropriate in practical and convenient if considering the whole concrete of the turbine foundation composite structure.