深度衰减效应对大型地下洞室群强震响应的影响分析

介绍了大型地下洞室群强震反应分析所需要输入地震波的选用原则,重点考虑了场地的深度衰减效应,同时提出了一种假设来确定地震危险性分析提供的峰值加速度的所在位置。选用了两组攀枝花实测地震记录,同时利用三角级数叠加法综合考虑了深度衰减效应,合成了一组人工地震动,使用ABAQUS软件对某水电站大型地下洞室群进行了二维非线性强震动力时程数值计算分析。结果表明:生成的地震波能较好地模拟地下洞室群的地震响应,深度衰减对地震响应结果有明显影响,不同频谱的地震波相对位移-时程差距较大,但频谱参数的影响还有待于深入研究。研究成果对大型地下洞室群地震动输入问题研究具有一定的指导意义。

Influence of depth attenuation on seismic response of large underground cavern group

The non-stationary seismic motion for large underground cavern group located in alpine gorge is artificially simulated, based on the frequency analysis of near-site seismic log and bedrock response spectrum obtained by seismic hazard analysis. The trigonometric series superposition, under the control of two predominant frequencies by the Fourier transform from Panzhihua earthquake records, is used to simulate the seismic motion with consideration of depth modification, baseline modification and high frequency wave. The other earthquake log with similar geological background is also used to get the frequency spectrum if the near-site earthquake log is absent. The finished artificial seismic motions, as the numerical simulations show, fit the numerical analysis software such as FLAC and ABAQUS well.