Geotechnical Site Characterization with 3-D Seismic Waveform Tomography

使用 3-D 地震波形断层扫描表征岩土工程场地

• 批准号: 1637557
• 负责人: Khiem Tran
• 金额: $ 20.62万
• 依托单位: Clarkson University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1637557&HistoricalAwards=false
• 关键词: Geotechnical; Site; Characterization; Seismic; Waveform

Unanticipated site conditions such as highly variable soil and rock layers with embedded low-velocity anomalies (soft soils or voids) cause significant problems during and after construction of foundations. Knowledge of the anomalies is crucial, as the anomalies can cause structural damage or collapse that can result in significant property damage and occasional loss of life. This award supports fundamental research to provide the knowledge needed to quantify embedded anomalies and characterize variable soil/rock layers at high resolutions. Results from this research will accelerate economical and practical implementation of innovative non-destructive testing (NDT) methods for protecting and improving our nation's infrastructure. The developed analysis can be used for material imaging and characterization at various scales from millimeters to hundreds of meters for several engineering applications such as evaluation of geotechnical subsurface site conditions, bridge foundation scour, concrete structural components, and asphalt pavements. The goal of this research is to characterize both shear wave (S-wave) and compression wave (P-wave) velocity profiles of 3-D subsurface structures at meter scales down to 30 meter depth from surface-based seismic wave fields. The subsurface structures consist of soil, rock, and voids filled by air or water. To achieve the goal, the research will include (i) to develop a three-dimensional full waveform inversion (3-D FWI) analysis of seismic wave fields for high-resolution (meter pixel) characterization of subsurface site conditions, and (ii) to verify the 3-D FWI analysis by full scale field experiments. Full seismic surface wave fields will be used to quantify embedded anomalies and characterize variable soil/rock layers, as the propagation properties of seismic waves are modulated by the anomalies and layer interfaces. The seismic wave fields are acquired from geophysical testing using sensors and sources located in uniform 2-D grids on the ground surface, and then inverted for the extraction of 3-D subsurface wave velocity structures. The research will address inherent issues of small scale tomography including dominant Rayleigh wave components, inconsistent wave excitation, strong attenuation, poor a priori information, and highly variable of near surface soil/rock. Using full information contained in the measured waveform data, the FWI analysis is expected to provide more detailed and accurate characterization of materials than methods currently used in practice, which use only portions of the measured data. This will result in new knowledge in the area of engineering geophysics, and it is a critical step toward using an effective geophysical method for site investigations to improve design of foundations and other geotechnical structures.

意外的地点条件，例如高度可变的土壤和具有嵌入式低速异常（软土或空隙）的岩石层在基础构造期间和建造期间引起了重大问题。 对异常的了解至关重要，因为异常可能会造成结构损害或崩溃，从而导致严重的财产损害和偶尔的生命丧失。 该奖项支持基本研究，以提供量化嵌入式异常所需的知识，并在高分辨率下表征可变的土壤/岩石层。 这项研究的结果将加速对保护和改善国家基础设施的创新非破坏性测试（NDT）方法的经济和实际实施。 开发的分析可用于从毫米到数百米的各种尺度上进行材料成像和表征，以用于几种工程应用，例如评估岩土技术地下位点条件，桥梁基础擦洗，混凝土结构组件和沥青路面。这项研究的目的是表征剪切波（S波）和压缩波（P波）的速度曲线，该速度谱图仪表结构在仪表仪表结构仪表仪表仪表仪表仪表仪均与基于表面的地震波场的深度低至30米。 地下结构包括土壤，岩石和空气或水填充的空隙。为了实现该目标，研究将包括（i）开发三维全波形反演（3-D FWI）对地震波场的地震场分析，以用于地下位点条件的高分辨率（仪表像素）表征，以及（ii）通过全尺度场实验验证3-D FWI分析。 全地震表面波场将用于量化嵌入异常并表征可变土壤/岩石层，因为地震波的传播特性由异常和层接口调节。 地震波场是从地球物理测试中获取的，使用位于地面上均匀的2-D网格的传感器和源，然后倒置以提取3-D地下波速度结构。 这项研究将解决小规模层析成像的固有问题，包括主要的瑞利波部件，不一致的波动激发，强大的衰减，较差的先验信息以及近地面土壤/岩石的高度变化。 使用测量的波形数据中包含的完整信息，与实践中当前使用的方法相比，FWI分析有望提供对材料的更详细和准确的材料表征，这些方法仅使用一部分测量数据。 这将导致工程地球物理学领域的新知识，这是使用有效的地球物理方法进行现场研究来改善基础和其他岩土技术结构的关键步骤。

项目成果

Site Characterization with 3-D Full Seismic Waveform Tomography

使用 3-D 全地震波形断层扫描进行现场表征

• DOI: 10.1061/9780784481615.019
• 发表时间: 2018
• 期刊: International Foundations Congress and Equipment Expo
• 作者: Tran, Khiem T.;Nguyen, Trung Dung
• 通讯作者: Nguyen, Trung Dung

Site Characterization with 3-D Elastic Full Waveform Tomography

使用 3D 弹性全波形断层扫描进行现场表征

• DOI: 10.1190/geo2017-0571.1
• 发表时间: 2018
• 期刊: GEOPHYSICS
• 影响因子: 3.3
• 作者: Nguyen, Trung Dung;Tran, Khiem T.
• 通讯作者: Tran, Khiem T.