大型水电站地下洞室群三维地震反应时域分析

3-D Seismic Analysis on Large-scale Underground Hydropower Station Caverns in Time Domain

建立了某水电站地下厂房洞室群的三维有限元模型,采用粘弹性边界及相应的地震动输入方法,进行了SV波竖直入射下的动力响应时域分析。分析结果表明:地震时,动位移、加速度幅值沿洞室断面高程逐渐增大;各洞室相交部位、洞脚、沿洞室轴向和横向突变部位的动拉、压应力较其他部位大;同一断面内沿高度方向垂直于洞室轴向的水平动位移和加速度在时程波形变化及频谱图上,各点非常接近,但动应力差别较大。

A 3-D finite element model for underground hydropower caverns was established to conduct seismic analysis in time domain.Viscoelatic boundary and corresponding seismic input method for vertical SV wave was adopted.The results show：the amplitude of dynamic displacement and acceleration increases with the increasing of elevation;the dynamic tensile and compressive stresses on the intersections,feet and abruptly changed site of caverns are larger than those at other locations;the displacement and acceleration on each point along the height of the cavern wall at the same section are nearly close in the time-waveform and Fourier spectrum,while the dynamic stress is rather different.