Site Characterization with 3-D Full Seismic Waveform Tomography
Site Characterization with 3-D Full Seismic Waveform Tomography
复制标题
使用 3-D 全地震波形断层扫描进行现场表征
DOI：
10.1061/9780784481615.019
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Nguyen, Trung Dung
中科院分区：
文献类型：
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作者：
Tran, Khiem T.;Nguyen, Trung Dung
提出了一种新的三维全波形反演方法。该方法是基于三维弹性波方程的解决方案的正演模拟波的传播，和交叉伴随梯度方法的模型更新提取材料属性。采用交错网格有限差分法求解波动方程，并采用完全匹配层条件进行边界截断。根据前向和后向波场计算梯度。在所有接收器位置处的多个源引起的反向时间位移残差用于模拟后向波场。地震波场是从地球物理测试中获得的，使用位于地面上均匀的2D网格中的传感器和源，然后反演以提取3D地下波速度结构。所提出的FWI方法的能力进行了测试合成和现场实验数据集。模拟资料的反演结果表明，三维FWI方法能够较好地描述横向变化的低速层和高速层。使用96个接收器和一个推进式能量发生器（PEG）来产生地震波能量，收集了现场实验数据。实测结果表明，波形分析能够描述不同的地下土层。地震反演结果与侵入式标准贯入试验（SPT）N值基本一致，包括低速带的识别。
A new three-dimensional full waveform inversion (3D FWI) method is presented for geotechnical site characterization. The method is based on a solution of 3D elastic wave equations for forward modeling to simulate wave propagation, and a cross-adjoint gradient approach for model updating to extract material property. The staggered-grid finite-difference technique is used to solve the wave equations, together with implementation of the perfectly matched layer condition for boundary truncation. The gradient is calculated from the forward and backward wavefields. Reversed-in-time displacement residuals are induced as multiple sources at all receiver locations for simulation of the backward wavefield. Seismic wavefields are acquired from geophysical testing using sensors and sources located in uniform 2D grids on the ground surface, and then inverted for extraction of 3D subsurface wave velocity structures. The capability of the presented FWI method is tested on both synthetic and field experimental datasets. The inversion results from synthetic data show the 3D FWI ability in characterizing laterally variable low-and high-velocity layers. Field experimental data were collected using 96 receivers and a propelled energy generator (PEG) to generate seismic wave energy. The field data result shows that the waveform analysis was able to delineate variable subsurface soil layers. The seismic inversion results are generally consistent with invasive standard penetration test (SPT) N-values, including identification of a low-velocity zone.