基于黏弹性边界的拱坝地震反应分析方法

无限地基的能量辐射效应是影响拱坝地震反应的一个重要因素。本文提出将一种新的黏弹性人工边界结合显式有限元的时域波动求解方法用于拱坝—地基系统的地震反应分析，地震动输入通过分别将底边界入射位移时程和侧边界自由场时程对应的解析应力时程作为边界荷载实现。该方法具有较高的计算精度，且不存在高、低频计算失稳问题。文中以小湾拱坝地震反应分析为例，比较了透射边界、黏弹性边界两种计算方法的计算结果，论证了本文建议方法的有效性。

Analysis method for seismic response of arch dams in time domain based on viscous-spring artificial boundary condition

A new method for analyzing the seismic response of arch dams in time domain by combining the viscous-spring artificial boundary with explicit finite element method is proposed, by which the influence of radiation damping on seismic response can be considered. In this method, the input of seismic waves is implemented by loading the node-force histories on the artificial boundary which are discrete analytic stress histories of the input-displacement field on the bottom boundary and the free field on the side boundary. This method not only avoids the numerical unstable phenomena of the existing combination method of the explicit FEM and the transmitting boundary in high and low frequency but also has highly computational accuracy. The seismic dynamic responses of the arch dam in Xiaowan Project are calculated by using this method.