ABSTRACT Migration is considered to be a key step in the data processing of the seismic advancement predictions of tunnels, and it directly affects the final interpretations. Therefore, with the goal of addressing the limitations of the current acoustic reverse‐time migration processes, as well as deepening the understanding of the interactions between different wave modes in traditional elastic reverse‐time migration, a vector P‐ and S‐wave reverse‐time migration method is proposed in this study. Consideration is given to the actual tunnel spaces, and forward calculations and reverse‐time extrapolations of the wavefields are carried out based on the first‐order velocity‐stress elastic wave equation of P‐ and S‐wave separation and a high‐order staggered‐grid algorithm. The imaging conditions of a source‐normalized cross‐correlation are used to realize the imaging. Then, a Laplace filtering method is adopted to suppress the low‐frequency artefacts. Numerical simulations of the weak interlayer and karst cave models show that the proposed method had the ability to more effectively suppress noise and achieve high‐precision imaging of tunnel spaces, when compared with using horizontal or vertical components to directly obtain the images. The positions and shapes within the tunnel spaces can be accurately imaged regardless of whether they are lithologic interfaces or local geological bodies. This is found to improve the resolution and accuracy of the tunnel advancement predictions. Finally, the proposed method is successfully applied to the real data processing, and the effects are found to be satisfactory.

中文翻译：

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隧道空间矢量纵横波叠前逆时偏移

摘要 偏移被认为是隧道地震超前预测数据处理的关键步骤，直接影响最终解释。因此，为了解决当前声学逆时偏移过程的局限性，以及加深对传统弹性逆时偏移中不同波模之间相互作用的理解，矢量P波和S波逆时偏移本研究提出时间偏移法。考虑实际隧道空间，基于纵横波分离的一阶速度-应力弹性波方程和高阶交错波场进行波场正演计算和逆时外推。网格算法。利用源归一化互相关的成像条件来实现成像。然后，采用拉普拉斯滤波方法来抑制低频伪影。弱夹层和岩溶洞穴模型的数值模拟表明，与使用水平或垂直分量直接获取图像相比，该方法能够更有效地抑制噪声并实现隧道空间的高精度成像。无论是岩性界面还是局部地质体，都可以准确地成像隧道空间内的位置和形状。发现这可以提高隧道前进预测的分辨率和准确性。最后，将所提方法成功应用于实际数据处理中，效果令人满意。