基于地脉动反演硬夹层场地剪切波速

发布时间：2018-01-24 04:04

本文关键词： 硬夹层扩展空间自相关法瑞雷波频散曲线剪切波速反演遗传算法　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：扩展空间自相关法能稳定、准确地从非规则地脉动台阵观测记录中提取场地的基阶瑞雷波频散曲线。针对硬夹层场地,基于扩展空间自相关法和遗传算法,本文构建了一套高效、较为可靠的场地剪切波速勘探方案,并将其应用于国内某一核电厂址硬夹层场地剪切波速结构的反演,反演结果与钻孔所给剪切波速结构较为一致。围绕剪切波速勘探方案的构建,本文展开了如下研究工作:(1)通过对比已有频散曲线正演方法的计算效率和精度,结果表明快速标量传递矩阵法的精度和计算效率均占优,进而将其确立为频散曲线反演中的正演方法;验证了基阶瑞雷波频散曲线反演存在多解这一命题,即存在显著差异的土层所对应频散曲线十分接近。分析了硬夹层场地基阶瑞雷波频散曲线的特征,讨论了频散曲线的截止频率问题,为后续反演工作提供较为坚实的基础。(2)详尽介绍了遗传算法在土层剪切波速反演中的应用,基于实例验证了目标函数及初始模型的选取将显著影响遗传算法收敛速度及精度。进而建立了一种初始模型构建策略及一类新的目标函数。分析了截止频率对硬夹层场地剪切波速反演的影响。(3)讨论了扩展空间自相关法与地脉动观测结合提取基阶瑞雷波频散曲线的影响因素:仪器的选择,台阵布置方案,包括台站的布置形式和台阵的半径大小,基于实例论证该方法的可靠性。(4)将扩展空间自相关法,遗传算法,瑞雷波频散曲线正演方法(快速标量传递法)结合以构建剪切波速勘探方案,详尽地阐述了该方案在国内某一核电厂址内硬夹层场地剪切波速结构中的应用,所得反演结果与钻孔所给剪切波速结构较为一致,这表明本文所建立剪切波速勘探方案是有效的。
[Abstract]:The extended spatial autocorrelation method can stably extract the fundamental Rayleigh wave dispersion curves from irregular ground pulsating array observation records. For hard sandwich sites, the extended spatial autocorrelation method and genetic algorithm are used. In this paper, a set of efficient and reliable site shear wave velocity exploration scheme is constructed and applied to the inversion of shear wave velocity structure of a nuclear power plant site with hard interlayer. The inversion results are consistent with the shear wave velocity structure given by the borehole. The results show that the fast scalar transfer matrix method is superior to the fast scalar transfer matrix method. Then it is established as a forward modeling method in the inversion of dispersion curve. It is proved that there are multiple solutions to the fundamental Rayleigh wave dispersion curve inversion, that is, the dispersion curve of the soil layer with significant difference is very close. The characteristics of the fundamental Rayleigh wave dispersion curve in the hard intercalation site are analyzed. The cutoff frequency of dispersion curve is discussed and the application of genetic algorithm in soil shear wave velocity inversion is introduced in detail. An example is given to verify that the selection of objective function and initial model will significantly affect the convergence speed and precision of genetic algorithm. Furthermore, an initial model construction strategy and a class of new objective functions are established. Influence of Shear Wave Velocity inversion on Sandwich site. 3) the influence factors of extracting the dispersion curve of the fundamental Rayleigh wave by the extended spatial autocorrelation method and the ground-pulsation observation are discussed: the choice of the instrument. Array layout scheme, including station layout form and array radius size, based on an example to demonstrate the reliability of the method. 4) will expand the spatial autocorrelation method, genetic algorithm. The forward modeling method of Rayleigh wave dispersion curve (fast scalar transfer method) is combined to construct the shear-wave velocity exploration scheme. The application of the scheme in the shear wave velocity structure of a nuclear power plant site with hard interlayer is described in detail. The inversion results are in good agreement with the shear wave velocity structure given by the borehole, which shows that the shear wave velocity exploration scheme established in this paper is effective.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU435;P631.4

【参考文献】