强震作用下特高拱坝非线性地震反应分析

研究采用等效一致黏弹性边界单元模拟拱坝无限地基辐射阻尼效应,给出了人工边界节点上等效地震荷载的计算公式,实现了拱坝-地基系统的地震动输入。以我国某特高拱坝为例,建立了拱坝-地基三维有限元分析模型,精细模拟了坝体体型、横缝、河谷形状、各类岩体以及主要地质构造。采用时程分析方法,综合考虑无限地基辐射阻尼效应、拱坝-库水动力相互作用、拱坝横缝动力接触非线性效应等因素,分析了拱坝-地基系统在强震作用下的动力响应,对拱坝抗震安全性进行了评价。研究成果为高拱坝设计提供了参考。

Analysis on nonlinear seismic response of super-high arch dam under strong seismic action

In this study，the equivalent consistent viscoelastic boundary element is adopted to simulate the infinite foundation radiation damping effect，and then the equations of equivalent seismic load on the artificial boundary nodes are given out，thus the seismic motion input for arch dam-foundation system is realized. By taking a super-high arch dam in China as the study case，a 3 － D finite element analysis model for the arch dam-foundation system is established; by which the body shape，the transverse joints，the canyon shape，all types of the rock masses therein and the main geological structures are elaborately simulated. The dynamic response of the arch dam-foundation system under strong seismic action is analyzed with time-history analysis method under the comprehensive consideration of the factors of the infinite foundation radiation damping effect，the dam foundation-reservoir dynamic interaction，the dynamic contact nonlinearity effect of transverse joints，etc. ，and then the seismic safety of the arch dam is evaluated. The study result provides a reference for the design concerned.