高频瑞雷波法正反演研究及其在工程场地勘查中的应用

发布时间：2017-12-28 06:10

本文关键词：高频瑞雷波法正反演研究及其在工程场地勘查中的应用　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：近地表剪切波速度是土木抗震设计、地震危险系数分析、场地介质抗剪切性质等研究的重要基础。因此,获取近地表横波速度信息是极为重要的。面波多道分析(Multi-channel Analysis of Surface Waves,简称MASW)是获取垂向剪切波速度剖面的一种有效方法。面波多道分析主要利用高频瑞雷波的大振幅特性提取近地表瑞雷波频率-速度谱。然后按某种准则从频率-速度谱中拾取频散曲线。最后进行频散曲线反演以获取横波速度剖面。本文针对面波多道分析在浅地表物性勘探方面的应用进行了研究,本文研究内容如下:(1)利用快速矢量传递法计算四层递增型地质模型、四层含低速软弱夹层地质模型和含高速硬夹层地质模型三种常见的地质模型的多模式频散曲线和叠加模式频散曲线,并指出进行叠加模式频散曲线反演是可行的,可以有效避免模式混叠问题;(2)利用交错网格高阶有限差分对均匀半空间地质模型、四层递增型地质模型、四层含低速软弱夹层地质模型、四层含高速硬夹层和四层递增型横向缓变地质模型进行瑞雷波数值模拟,并提取频率-速度谱和叠加模式频散曲线解析解进行对照,并对瑞雷波数值模拟中具体的细节进行了详细的讨论;(3)讨论了具有不同波速结构的地质模型的观测系统设计问题,讨论结果表明对于递增型地质模型,面波能量占优的炮检距最长,含低速软弱夹层地质模型次之,含高速硬夹层地质模型最短,并对面波多道分析(MASW)的适用范围和局限性进行了讨论;(4)比较τ-p变换、频率分解法、高分辨率线性拉东变换(High Resolution Linear Radon Transform,简称HRLRT)获取的频率-速度谱的分辨率和频散曲线提取解的精度。比较结果表明高分辨率线性拉东变换,获得的瑞雷波频率-速度谱分辨率最高,频散曲线提取解精度最高;(5)引入确定性全局寻优算法广义模式识别(Generalized Pattern Search,简称GPS)对频散曲线进行反演,并对六层递增型地质模型、六层含低速软弱夹层地质模型和六层含高速硬夹层地质模型的频散曲线进行反演,反演结果表明,GPS算法对于各种地质模型都能高精度地重建;(6)最后,将本文采取的叠加模式频散曲线反演应用于吉林大学校园场地一组实测数据,以产生一维横波速度剖面;按照一维横波速度剖面获取方法,对某地两条测线多组实测数据进行处理,获取多个一维横波速度剖面,多个一维横波速度剖面组合为一二维矩阵,二维矩阵经插值光滑后,便可获得二维横波速度剖面。
[Abstract]:The near surface shear wave velocity is an important foundation for the research of civil seismic design, the analysis of seismic risk coefficient, and the anti shear properties of the medium. Therefore, it is very important to obtain the velocity information of the near surface shear wave. Surface wave multichannel analysis (Multi-channel Analysis of Surface Waves) is an effective method for obtaining vertical shear wave velocity profiles. The surface wave multichannel analysis mainly uses the large amplitude characteristics of high frequency Leibo to extract the frequency - velocity spectrum of the near surface surface Switzerland Leibo. Then the frequency dispersion curve is picked up from the frequency - velocity spectrum according to some criterion. Finally, the frequency dispersion curve is retrieved to obtain the transverse wave velocity profile. This paper studied the multichannel surface wave analysis applied in shallow surface physical exploration, the research contents of this paper are as follows: (1) calculation of four layer multi mode frequency increasing geological model and four layer with low velocity geological model and soft interlayer containing high speed hard interlayer geological model of three kinds of geological model and dispersion curve overlay mode dispersion curves using fast vector transfer method, and points out that the superposition mode dispersion curve inversion is feasible, can effectively avoid the mode mixing problem; (2) using high order staggered grid finite difference in homogeneous half space geological model, geological model, four layer increasing four layer with low velocity layer geological model, four layers and four layers with high speed hard interlayer increasing corrosion simulated horizontal Rui Leibo numerical geologic model, and extract the frequency spectrum and velocity superposition solution control mode frequency dispersion curve analysis, and the Swiss Leibo The specific details of the numerical simulation are discussed in detail; (3) discuss the observation system design problem with different geological model velocity structure, the result shows that the increasing of geological model, surface wave energy maximum offset is the longest, with low velocity layer geological model, including high speed hard interlayer the geological model of the shortest, and surface wave multichannel analysis (MASW) the scope and limitations are discussed; (4) comparison of tau -p transform, frequency decomposition method, high resolution linear Radon transform (High Resolution Linear Radon Transform, referred to as HRLRT) extraction solution accuracy resolution and dispersion curves obtained in frequency speed spectrum. The comparison results show that the high resolution linear Radon transform, frequency - Rui Leibo obtained the highest resolution of velocity spectrum, dispersion curve extraction solution of the highest accuracy; (5) introducing deterministic global optimization algorithm for generalized pattern recognition (Generalized Pattern Search, referred to as GPS) inversion of the dispersion curve, and the six layer six layer type geological increasing with low velocity model, geological model of weak interlayer and six layer with high speed hard interlayer geological model of dispersion curve inversion, the inversion results show that the GPS algorithm for various geological models are capable of high precision reconstruction; (6) the most, this paper will adopt the mode superposition frequency dispersion curve inversion applied to a set of measured data of Jilin University campus site, with the shear wave velocity profile generated according to the one-dimensional shear wave velocity profile; one-dimensional acquisition method, in two lines of multiple sets of measured data, obtaining a plurality of one-dimensional shear wave velocity profile, The velocity profiles of a number of one-dimensional transverse waves are combined into a two-dimensional matrix, and the two-dimensional transverse wave velocity profile can be obtained after the two-dimensional matrix is interpolated smooth.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P631.4

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