| 常Q滞弹性介质地震波动数值模拟——时域本构优化逼近 |
| |
| 引用本文： | 谢志南,郑永路,章旭斌.常Q滞弹性介质地震波动数值模拟——时域本构优化逼近[J].地球物理学报,2018,61(10):4007-4020. |
| |
| 作者姓名： | 谢志南 郑永路 章旭斌 |
| |
| 作者单位： | 中国地震局工程力学研究所, 中国地震局地震工程与工程振动重点实验室, 哈尔滨 150080 |
| |
| 基金项目： | 国家科技支撑计划课题（2015BAK17B01），国家自然科学基金（51678539），黑龙江省国家科技重大专项和重点研发项目省级资助资金（GX16C006）资助. |
| |
| 摘 要： | 在地震波动模拟中计入常Q滞弹性阻尼，可有效降低模拟波形的误差.就时域有限差分和有限元模拟而言，常基于广义标准线性体建立阻尼介质的时域本构逼近.广义标准线性体由若干标准线性体并联得到，增加标准线性体个数能有效提高模拟精度，但计算量及计算存储将成倍增长.目前尚未有普适的标准线性体个数优化取值方案.本文基于广义标准线性体参数的非线性优化拟合方法，详细分析了时域本构逼近误差的影响因素，清楚揭示了逼近误差仅取决于频带宽度，与频带上下限取值无关这一特性，阐明了构建具有普适性标准线性体个数优化取值方案的可行性.论证了波形模拟精度主要取决于波传播距离与模拟波长的比值以及标准线性体的个数取值.综合考虑上述两个控制因素，结合在波动正反演问题中广为采纳的波形时频误差衡量准则，对不同Q值介质给出了标准线性体个数优化取值表.进一步，本文提出采用不同个数标准线性体以近似不同Q值的阻尼介质时域本构，解决了以往波动数值模拟中统一采用相同个数标准线性体而导致的计算量及计算存储浪费或模拟精度低下等问题，并基于数值实验验证了这一方法的精度.本文工作对推进滞弹性介质波动数值模拟及其在全波形反演问题中的应用具有理论价值和实践意义.
|
| 关 键 词： | 滞弹性 地震波动模拟 常Q 广义标准线性体 时域本构 |
| 收稿时间： | 2017-11-13 |
Optimized approximation for constitution of constant Q viscoelastic media in time domain seismic wave simulation |
| |
| XIE ZhiNan,ZHENG YongLu,ZHANG XuBin.Optimized approximation for constitution of constant Q viscoelastic media in time domain seismic wave simulation[J].Chinese Journal of Geophysics,2018,61(10):4007-4020. |
| |
| Authors: | XIE ZhiNan ZHENG YongLu ZHANG XuBin |
| |
| Institution: | Key Laboratory of Earthquake Engineering and Engineering Vibration, Institute of Engineering Mechanics, China Earthquake Administration, Harbin 150080, China |
| |
| Abstract: | Taking into account viscoelastic damping effect of media with constant Q, the error of the synthetic waveform can be effectively reduced in seismic wave simulation. In term of time domain finite difference or finite element method for wave simulation, the generalized standard linear body (GSLS), consisted of several standard linear bodies (SLS) connected in parallel, is used to approximate the constitution of viscoelastic media. Via increasing the number of SLS, the accuracy of simulation can be effectively improved but simultaneously increasing the amount of both computational work and memory by times. It is not available yet a general instruction for the choices of the number of SLS in viscoelastic wave simulation, which is the main focus of this paper. The factors that impact on the GSLS approximation error are firstly analyzed with the parameter of GSLS fitted by a nonlinear optimization approach. Via clarifying that the error depends on the bandwidth but not the specific value of upper and lower limits of frequency interval, the feasibility of deriving such an instruction is illustrated. Moreover, for given bandwidth and the given number of SLS used in GSLS, the accuracy of synthetic waveform simulation is demonstrated to be impacted by both the factor of the ratio of wave propagation distance to the interested wavelength in simulation and the factor of the Q value of the media. Incorporating of the two factors, the table for optimal choice of the SLS number for medium with different Q value is established by using a generally applied criterial for measurement of time-frequency goodness-of-fit of the synthetic and the observed waveform. On basis of the new table, a method of using GSLS with different number of SLS for modelling media with different Q values is proposed to avoid the waste of the computational work and memory or the deterioration of the accuracy of simulation caused by using the same number of SLS in GSLS to approximate media with large spanned Q value, which is usually presented in seismic wave simulation. Finally, the accuracy and the efficiency of new method are validated by numerical tests. The work of this paper could further promote the wide application of viscoelastic wave simulation in forward problem and in inverse problem using full waveform inversion technique. |
| |
| Keywords: | Viscoelasticity Seismic wave simulation Constant Q Generalized standard linear solid Time-domain constitution |
| 本文献已被 CNKI 等数据库收录！ |
| 点击此处可从《地球物理学报》浏览原始摘要信息 |
| 点击此处可从《地球物理学报》下载免费的PDF全文 |
