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            论文编号:lw201901291022303969 所属栏目:代写留学生作业 发布日期:2019年01月29日 论文作者:论文网

            The objective of this experiment was to determine the underground layer structure of a local damand thelocation of anunderground pipe related to this dam. This was achieved by measurements using near-surface geophysical methods, including ground-penetrating radar (GPR), electrical resistivity tomography (ERT) and induced polarization (IP). It was determined thatthe area selected consists ofclayey formation and silty formation, while the pipe is at a depth of 0.3-0.4 m. Based on the results of this study, it is recommended thatGPR, ERT and IP measurements should be used together to achieve quantitative and reliable data for the underground layer structures, and transmitters with various frequencies should be used in the GPR detection.

            I. Introduction 导言
            近地表特征,即位于阴影地下区域(通常深度小于10米)的特征,具有重要的科学和实际意义,因为它们可以作为潜在地震的指标,是生物地球化学研究的基本要素。而且,这些特征对人类活动具有显着影响,例如有害物质的构造,隧道和存储。因此,迫切需要容易且精确地检测近表面特征以便于研究这些特征。近地表地球物理学(NSG)是指利用地球物理方法精确检测近地表特征(Everett,2013)。与传统的地球物理方法相比,NSG在几个关键方面有所不同。例如,NSG提供横向分辨率,但需要一些专业技术可能存在公共健康和安全问题。到目前为止,各种NSG方法已被应用于近地表特征的检测,包括磁,电和电磁方法。每种方法都有其自身的优点和局限性,因此适用于不同的应用。在这些方法中,探地雷达(GPR)方法,电阻率层析成像(ERT)和诱导极化(IP)方法是最广泛使用的方法,因为它们具有高分辨率,非侵入性和成本效益等优势(Butler,2005) 。在该实验中,通过GPR,ERT和IP测量坝,并且基于这些测量确定地下管的位置。
            Near-surface features, namely those lying in the shadow subsurface area (typically with depth less than 10 m),areof great scientific and practical importance as they can be an indicator of potential earthquakes and are essential elements of biogeochemical study. Moreover, these featureshave a significant effect onhuman activities suchas construction, tunneling and storing of hazardous materials. Therefore, facile and precise detection of near-surface features are urgently needed to facilitate the study of these features. Near-surface geophysics (NSG) refers to the utilization of geophysical methods for precise detections of near-surface features(Everett, 2013).Compared with traditional geophysicsmethods, NSG is differentin several key aspects.For example, NSGprovides lateral resolution,though it requires some specialized techniques and may havepublic health and safety concerns.To date, a variety of NSG methods have been applied in detections ofnear-surface features, including magnetic, electric and electromagnetic methods.Each method has its own advantages and limitations, thus suitable for different applications. Among these methods, the ground penetrating radar(GPR) method, theelectrical resistivity tomography(ERT) and theinduced polarization (IP) method are most widely used ones due to their superioradvantages such as high resolution,non-invasiveness and costeffectiveness(Butler, 2005). In this experiment, the dam was measured by GPR, ERT and IP and the location of the underground pipe was determined based on these measurements.
            Table of Contents
            Abstract 3
            I. Introduction 4
            II. Experimental Procedures 6
            2.1 Measurement by ground penetrating radar (GPR) 6
            2.2 Measurements by electrical resistivity tomography and induced polarization 8
            III. Results and discussion 10
            3.1 Ground penetrating radar 10
            3.2 Electrical resistivity tomography 11
            3.3 Induced polarization 12
            IV. Conclusions 14
            V. Recommendations 14
            Appendix A 15
            Appendix B 17
            Appendix C 19
            V. Recommendations
            Based on the results of this study, several recommendations and suggestions can be given. Firstly, it is recommended that GPR, ERT and IP measurements should be used together to achieve quantitative and reliable data for the underground layer structures. GPR is a non-invasive detection method can yieldresults with superiorvertical resolution,while its depth range is highly dependent onthe electrical conductivity of theground.The ERTand IP methodsare excellent methods for the identification of transitional boundaries in subsurface layers, but are time-consuming. Then, GPR tr
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