考虑道间时差相位的多道瞬态瑞雷波探测方法

发布时间：2018-03-25 01:32

  本文选题：多道瞬态瑞雷波探测　切入点：道间时差相位　出处：《中国地质大学(北京)》2017年硕士论文

【摘要】：自20世纪70年代以来,瑞雷波探测方法在工程中逐步得到认可和应用,目前,多道瞬态瑞雷波勘探已经成为工程中较为常用的物探方法之一。囿于波动问题空间采样率观念的限制,现有多道瞬态瑞雷波探测方法采用小道间距、多道检波器排列方式观测同一次激发的瞬态瑞雷波,虽然解决了同时观测不同频率成分波动的问题,但一个排列的多道检波器只能得到一条瑞雷波相速度—探测深度曲线,工作效率和横向分辨力受到极大限制。另外,对于瑞雷波相速度成像的波速分级,一直以来都没有形成一个固定的参考标准,这使得对瑞雷波探测结果的解译具有很大的主观性和局限性,同时,现有瑞雷波成像结果主要表达二维的剖面图,这中表达方式很难去直观、准确地揭示工程岩体中岩溶构造等不良地质体的规模、空间分布和连通状态。本文针对现有方法的弱点,对瞬态瑞雷波相速度的提取及其探测结果成像进行了研究,得到了以下三点认识:(1)提出了考虑道间时差相位的瞬态瑞雷波相速度提取的理论方法,形成了解算多道瞬态瑞雷波探测深度的新技术,这种方法突破了传统采样定理的要求,摆脱了现有方法道间距对频率成分的束缚,只用两道检波器的瞬态瑞雷波记录即可提取多种频率成分波动的相速度,完成现有方法一个多道检波器排列才能完成的工作,大大提高了探测的工作效率和横向分辨力。(2)提出了瑞雷波相速度分级方案,通过对场地及其周边的岩土体试样进行波速测试,建立了瑞雷波相速度分级与岩土体及岩溶破碎带性状的对应关系,为工程岩体瑞雷波相速度成像奠定了物理基础。(3)利用实测获取的工程岩体瑞雷波相速度的空间分布数据,依托于贵阳地铁岩溶洞穴探测项目研究建立的瑞雷波相速度与工程岩体性状对应的瑞雷波相速度分级方案,以沿测线的瑞雷波相速度—深度成像剖面和不同深度的瑞雷波相速度成像水平切片按照剖面和切片的空间位置组合,实现了工程岩体瑞雷波相速度空间分布的三维可视化;从瑞雷波相速度三维可视化空间展布图中,可以直观地看出岩溶破碎带的尺度大小、空间位置和连通状态。这种利用瑞雷波相速度空间数据构建瑞雷波相速度三维成像,直观、准确地揭示工程岩体中岩溶构造的规模、空间分布和连通状态的探测成果,在工程中尚无先例。这一探测方法在位于强岩溶富水区的贵阳地铁工程岩体岩溶探测中应用,探测结果与施工揭露的岩溶实际情况非常吻合,验证了方法的合理性和正确性,为地铁工程岩溶病害治理提供了有力的技术支撑。
[Abstract]:Since the 1970s, Rayleigh wave detection methods have been gradually recognized and applied in engineering. Multi-channel transient Rayleigh wave exploration has become one of the commonly used geophysical prospecting methods in engineering. Due to the limitation of spatial sampling rate concept of wave problem, the existing multi-channel transient Rayleigh wave detection methods adopt small track spacing. The transient Rayleigh waves excited by the same excitation are observed by the arrangement of multichannel geophone. Although the problem of simultaneously observing the fluctuation of different frequency components is solved, only one Rayleigh wave phase velocities and detection depth curves can be obtained by an arranged multichannel geophone. Working efficiency and lateral resolution are greatly restricted. In addition, there has been no fixed reference standard for Rayleigh wave phase velocity classification. This makes the interpretation of Rayleigh wave detection results very subjective and limited. At the same time, the existing Rayleigh wave imaging results mainly express two-dimensional profile, which is difficult to be intuitionistic. The scale, spatial distribution and connected state of poor geological bodies such as karst structures in engineering rock mass are accurately revealed. In this paper, the phase velocity extraction of transient Rayleigh waves and the imaging results of the transient Rayleigh waves are studied in view of the weakness of the existing methods. A theoretical method of phase velocity extraction of transient Rayleigh waves considering the phase of time difference between tracks is proposed, which forms a new technique for calculating the detection depth of multi-channel transient Rayleigh waves. This method breaks through the requirements of the traditional sampling theorem. In order to get rid of the restriction of channel spacing on frequency component, the phase velocity of frequency fluctuation can be extracted only by the transient Rayleigh wave record of two geophone, and the work of a multichannel detector arrangement can be accomplished by the existing method. The Rayleigh wave phase velocity classification scheme is proposed, which is used to measure the wave velocity of rock and soil samples in and around the site. The corresponding relationship between Rayleigh wave phase velocity classification and the characteristics of rock, soil and karst fracture zone is established, which lays a physical foundation for Rayleigh wave phase velocity imaging of engineering rock mass. Based on the research of Guiyang metro karst cave exploration project, the Rayleigh wave phase velocity classification scheme corresponding to the characteristics of engineering rock mass is established. The 3D visualization of Rayleigh wave phase velocity distribution in engineering rock mass is realized by combining the Rayleigh wave phase velocimetry profile along the line and the Rayleigh wave phase velocity imaging horizontal section of different depths according to the spatial position of the section and slice. From the 3D visualization space layout of Rayleigh wave phase velocity, the size, spatial position and connected state of karst broken zone can be seen intuitively. This kind of 3D image of Rayleigh wave phase velocity is intuitively constructed by using Rayleigh wave phase velocity spatial data. There is no precedent to reveal the scale, spatial distribution and connected state of karst structure in engineering rock mass accurately. This method is applied in karst detection of Guiyang metro engineering rock mass in strong karst and rich water area. The results of detection are in good agreement with the actual situation of karst exposed by construction, which verifies the rationality and correctness of the method and provides a strong technical support for the treatment of karst diseases in subway engineering.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P631.4
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本文编号：1660966