Abstract Detailed information of soil/rock variability and properties for the entire volume of supporting materials is crucial for the successful design and construction of deep foundations. Traditional invasive testing methods such as the standard penetration test (SPT) and the cone penetrometer test (CPT) only sample a small volume of soil/rock properties near the device's tip. Surface-based seismic methods can provide overall subsurface conditions but are limited to shallow depths due to the dominancy of surface waves. To address this issue, we present a novel SPT-seismic testing method for deep site characterization. Seismic wavefields generated by SPT blows at various depths are recorded by a 2D grid of geophones on the ground surface, and analyzed by a 3D full-waveform inversion (3D FWI) to extract subsurface material properties. Unlike surface-based wavefields dominated by surface waves propagating near the ground surface, the SPT-seismic wavefields are rich in body waves propagating from great depths that allow extracting detailed material properties at depths. The method is tested on in-depth source synthetic data and SPT-source field data. The results of the synthetic experiment indicate that the method successfully images soil layering with a buried anomaly. Field experiment results provide new insights into its utility as a viable geophysical tool for deep site characterization. 3D subsurface S-wave and P-wave velocities within 9 m around the SPT boring are well characterized, including two deep voids at 14–18 m depth. Comparison with the surface-based 3D FWI method proves the superiority of the presented method in imaging deep structures. S-wave velocity values of the final inverted result are also compared with SPT N-values and a good overall agreement over the whole depth is observed.

中文翻译：

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SPT 和 3D 全波形反演的耦合，用于深场表征

摘要 整个支撑材料体积的土壤/岩石可变性和特性的详细信息对于深基础的成功设计和施工至关重要。传统的侵入性测试方法，例如标准渗透测试 (SPT) 和锥形渗透计测试 (CPT)，仅对设备尖端附近的少量土壤/岩石特性进行采样。基于地表的地震方法可以提供整体的地下条件，但由于表面波的优势而仅限于浅层。为了解决这个问题，我们提出了一种用于深部场地表征的新型 SPT 地震测试方法。SPT 冲击在不同深度产生的地震波场由地表检波器的 2D 网格记录，并通过 3D 全波形反演 (3D FWI) 进行分析以提取地下材料特性。与由在地表附近传播的表面波主导的地基波场不同，SPT 地震波场富含从深海传播的体波，可以在深处提取详细的材料特性。该方法在深度源合成数据和SPT源现场数据上进行了测试。综合实验结果表明，该方法成功地对埋藏异常的土壤分层进行了成像。现场实验结果为其作为一种可行的地球物理工具用于深部场地表征提供了新的见解。SPT 钻孔周围 9 m 范围内的 3D 地下 S 波和 P 波速度得到了很好的表征，包括两个深度为 14-18 m 的深空洞。与基于表面的 3D FWI 方法的比较证明了所提出的方法在成像深部结构方面的优越性。