空间相关的非平稳地震动场合成思路及程序实现

Synthesis Thought and Program Realization of Non-stationary Spatially Variable Ground Motions

为了得到空间相关的非平稳地震动场,在分析地震动时频非平稳特性与相位差的关系及物理意义的基础上,推导了空间相关的非平稳地震动场的合成思路及简化分析方法:即通过功率谱矩阵进行CHOLESKY分解得到傅里叶幅值谱和相关相位角,基于相位差谱得到初始相位角,采用快速傅里叶变换得到时频非平稳的地震动场.基于此合成思路,编制了空间相关的非平稳地震动合成程序及交互式前后数据处理窗口.以某实际空间场地为算例,拟合得到了空间各支承点地震动时程.算例结果表明,本文编制的合成程序可以为多点激励地震响应分析提供空间相关的时频非平稳地震动场.

This paper is aiming to synthesize Non-stationary Spatially Variable Ground Motions（NSVGMs）.After analyzing the relationship between time-frequency non-stationary characteristics and phase differences,the simulating method of Non-stationary Spatially Variable Ground Motions（NSVGMs）is proposed in this paper.In the simulation progress,amplitudes and related phases are calculated from the CHOLESKY decomposition of the power spectrum matrix,and the initial phase is obtained from the phase differences spectrum.Then the NSVGMs are synthesized by IFFT method.Based on the proposed method,aprogram to synthesize NSVGMs with interactive interface is compiled.Finally,a series NSVGMs of certain spatial sites are synthesized by this program.Results of the computational example show that this synthesis program can effectively provide NSVGMs for multi-excitation seismic analysis.