新丰江水库大坝强震动监测及其动力特性分析

摘要

新丰江水库大坝是世界上第一座经受六级地震考验的超百米高混凝土大坝,并且至今库区周围仍然有地震不断发生,因此对其进行抗震分析十分必要.首先利用大坝强震动台阵的监测数据进行模态分析,然后结合模态分析结果建立大坝典型引水坝段ANSYS有限元模型并对其进行静力和动力分析,探讨坝体的变形和应力分布规律.结果表明:大坝模态频率与水位负相关;大坝在地震作用下,上游坝面突变处出现最大拉应力,这一现象与挡水坝段上游坝面突变处出现贯穿裂缝的破坏结果是一致的,应当引起一定重视,静力作用和地震作用下其他部位均有一定的安全储备;动力时程分析结果与反应谱分析结果相比,前者更加偏于安全.%Xinfengjiang reservoir dam is the first dam which has withstood the test of an earthquake of magnitude 6 in the world.Nowadays earthquakes still occur frequently in the reservoir area.Therefore,it is necessary to carry out a seismic analysis for the purpose to estimate the safety level of the dam.Firstly,the data of dam strong motion array are used to conduct modal analysis.Then combined with modal analysis results,the finite element analysis software,i.e.ANSYS,is used to carry out statical and dynamical analysis of the typical diversion section to explore the deformation and stress distribution rules of the dam.The results show that dam modal frequency is inverse proportion with water level.Under earthquake action,the maximum tensile stress occurs the dam upstream surface's mutation.The phenomenon is consistent to that of the penetrating crack on the retaining dam upstream surfacers mutation.This should cause a certain value.Other parts have a certain safety stock under static and earthquake action.Dynamic time history analysis result is safer than the response spectrum analysis results.