剪切波速测试资料反演计算方法应用研究
发布时间：2018-10-05 12:59
【摘要】：在抗震研究领域,土层的剪切波速值的大小不仅能够反映场地传播地震波能力的大小,同时它也是描述土体动力特性的一个重要参数。在工程中,常用剪切波速来确定土层覆盖层厚度,判别砂土或粉土地基的地震液化、建筑场地类别,计算土体的动剪切模量等。因此,对剪切波速研究有实际的工程意义和理论价值。对于土这种复杂的地质体,由于结构、成因、形成历史和成分的不同,使得剪切波速在不同的土层和不同的条件下都表现出很大的差异。目前国内外对于剪切波的测试,一方面由于测试的手段和测试条件的限制,使获得土层剪切波速的资料增加了困难或测试的不够理想;另一方面在获取剪切波速测试数据后,为了计算的简便对其采用了很多的近似处理,这些都给剪切波速的测试带来了一定的误差。因此,本文就获得剪切波速资料后,如何既方便简单又能保证精度的前提下计算出土层的剪切波速值进行研究。本文围绕土层剪切波速资料开展了如下工作。1、对目前剪切波速测试的问题进行了详细的阐述,分析了CT(Computerized Tomography计算机层析成像)技术在处理剪切波速资料方面的应用,并对CT技术的内容、发展以及在地球物理领域的应用进行了简单的介绍。2、详细介绍了我国工程界广泛使用的土层剪切波速测试的各种仪器的原理和使用方法。对各种仪器的适用范围、各种测试方法和资料整理分析的方法进行了对比分析,指出了各自的优缺点,并选择将CT技术运用于目前运用最多最方便的单孔法测试中。3、详细的介绍了CT技术中的理论知识:地球物理反演理论。主要介绍了反演理论的概念,数学物理模型以及反演问题解的特性,并着重介绍了地震波速度反演技术(CT)的研究进展和求解方法。4、分析运用走时反演成像理论,模拟单孔测试的方法,假设波从激发点激发到接收点接收是沿直线传播的,详细的介绍了单孔CT技术的基本原理,同时详细的介绍了如何在MATLAB中实现这样的传播模型。5、介绍了反演算法的基本原理,并详细的介绍了运用联合迭代法(SIRT)求解走时反演问题的具体过程,以及在MATLAB环境中实现这样过程的具体步骤。6、以芜湖市某工程为例,选取了场地的两个钻孔的单孔测试资料进行反演计算,并将反演结果与单孔法测试的传统计算方法进行对比分析,证明了上述直线路径反演算法的正确性和可行性,同时对于其不足之处和尚需改进的方面也作了说明。
[Abstract]:In the field of seismic research, the value of shear wave velocities of soil layer can not only reflect the magnitude of seismic wave propagation capacity, but also is an important parameter to describe the dynamic characteristics of soil. In engineering, shear wave velocity is commonly used to determine the thickness of soil cover, to distinguish the seismic liquefaction of sand or silt foundation, to classify the building site, and to calculate the dynamic shear modulus of soil. Therefore, the study of shear wave velocity has practical engineering significance and theoretical value. For a complex geological body such as soil, due to the difference in structure, origin, formation history and composition, shear wave velocities show great differences in different soil layers and different conditions. At present, the testing of shear wave at home and abroad, on the one hand, because of the limitation of testing means and testing conditions, makes it more difficult to obtain the data of shear wave velocity of soil layer or is not good enough for testing; on the other hand, after obtaining the data of shear wave velocity measurement, For the sake of simplicity of calculation, many approximate treatments are used, which bring some errors to the measurement of shear wave velocity. Therefore, after obtaining the shear wave velocity data, how to calculate the shear wave velocity of soil layer on the premise of convenience, simplicity and accuracy is studied in this paper. In this paper, the following work has been done around the soil shear wave velocity data: 1. The current problems of shear wave velocity measurement are described in detail, and the application of CT (Computerized Tomography computer tomography technology in the processing of shear wave velocity data is analyzed. The content, development and application of CT technology in geophysics are briefly introduced. The principle and method of various instruments for measuring shear wave velocity of soil layer widely used in engineering field in China are introduced in detail. The scope of application of various instruments, various testing methods and methods of data arrangement and analysis are compared and analyzed, and their respective advantages and disadvantages are pointed out. And choose to use CT technology in the most convenient single hole method test at present. It introduces the theory knowledge of CT technology in detail: geophysical inversion theory. This paper mainly introduces the concept of inversion theory, mathematical and physical model and the characteristics of inversion problem solution, and emphatically introduces the research progress and solution method of seismic wave velocity inversion technique (CT), and analyzes the application of traveling time inversion imaging theory. The method of simulating the single hole test assumes that the wave propagates along a straight line from the excitation point to the receiving point. The basic principle of the single hole CT technique is introduced in detail. At the same time, it introduces in detail how to realize this propagation model in MATLAB, introduces the basic principle of inversion algorithm, and introduces in detail the concrete process of solving the traveling time inversion problem by using joint iteration method (SIRT). Taking a project in Wuhu City as an example, the single hole test data of two boreholes in the site are selected for inversion calculation. The inversion results are compared with the traditional calculation method tested by the single hole method, which proves the correctness and feasibility of the above algorithm. At the same time, the inadequacies of the algorithm and the aspects that need to be improved are also explained.
【学位授予单位】：安徽建筑大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU435
本文编号：2253477
[Abstract]:In the field of seismic research, the value of shear wave velocities of soil layer can not only reflect the magnitude of seismic wave propagation capacity, but also is an important parameter to describe the dynamic characteristics of soil. In engineering, shear wave velocity is commonly used to determine the thickness of soil cover, to distinguish the seismic liquefaction of sand or silt foundation, to classify the building site, and to calculate the dynamic shear modulus of soil. Therefore, the study of shear wave velocity has practical engineering significance and theoretical value. For a complex geological body such as soil, due to the difference in structure, origin, formation history and composition, shear wave velocities show great differences in different soil layers and different conditions. At present, the testing of shear wave at home and abroad, on the one hand, because of the limitation of testing means and testing conditions, makes it more difficult to obtain the data of shear wave velocity of soil layer or is not good enough for testing; on the other hand, after obtaining the data of shear wave velocity measurement, For the sake of simplicity of calculation, many approximate treatments are used, which bring some errors to the measurement of shear wave velocity. Therefore, after obtaining the shear wave velocity data, how to calculate the shear wave velocity of soil layer on the premise of convenience, simplicity and accuracy is studied in this paper. In this paper, the following work has been done around the soil shear wave velocity data: 1. The current problems of shear wave velocity measurement are described in detail, and the application of CT (Computerized Tomography computer tomography technology in the processing of shear wave velocity data is analyzed. The content, development and application of CT technology in geophysics are briefly introduced. The principle and method of various instruments for measuring shear wave velocity of soil layer widely used in engineering field in China are introduced in detail. The scope of application of various instruments, various testing methods and methods of data arrangement and analysis are compared and analyzed, and their respective advantages and disadvantages are pointed out. And choose to use CT technology in the most convenient single hole method test at present. It introduces the theory knowledge of CT technology in detail: geophysical inversion theory. This paper mainly introduces the concept of inversion theory, mathematical and physical model and the characteristics of inversion problem solution, and emphatically introduces the research progress and solution method of seismic wave velocity inversion technique (CT), and analyzes the application of traveling time inversion imaging theory. The method of simulating the single hole test assumes that the wave propagates along a straight line from the excitation point to the receiving point. The basic principle of the single hole CT technique is introduced in detail. At the same time, it introduces in detail how to realize this propagation model in MATLAB, introduces the basic principle of inversion algorithm, and introduces in detail the concrete process of solving the traveling time inversion problem by using joint iteration method (SIRT). Taking a project in Wuhu City as an example, the single hole test data of two boreholes in the site are selected for inversion calculation. The inversion results are compared with the traditional calculation method tested by the single hole method, which proves the correctness and feasibility of the above algorithm. At the same time, the inadequacies of the algorithm and the aspects that need to be improved are also explained.
【学位授予单位】：安徽建筑大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU435
【参考文献】
相关期刊论文 前3条
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3 任永朝;唐杰生;;层析成像(CT)技术在工程勘察中的应用[J];中国非金属矿工业导刊;2008年04期
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