Detection of urban underground cavities using seismic scattered waves: a case study along the Xuzhou Metro Line 1 in China

作者：Jun Zhang, Shengdong Liu, Cai Yang, Xue Liu, Bo Wang · 发表于：Near Surface Geophysics · 年份：2020 · DOI：10.1002/nsg.12132 · 被引用次数：16 · 研究领域：Seismic Waves and Analysis、Geophysical Methods and Applications、Seismic Imaging and Inversion Techniques

ABSTRACT During metro construction, unidentified cavities pose a serious threat to the integrity of the tunnels and public safety. An efficient and accurate cavity‐detection method is needed, given the limited space and time constraints of urban construction. Equivalent offset migration is a high‐accuracy, seismic scattered‐wave imaging method that is effective in wavefield extraction, has the ability to derive the wavefield outside the range of the source–receiver points and can use imaging data for areas with poor signal‐to‐noise ratios. In this study, we consider a stratified subsurface structure and the geological conditions of a city and construct a typical urban cavity geological model to study the characteristics of cavity‐scattered waves. In numerical studies, equivalent offset migration is superior to Kirchhoff post‐stack migration in the case of seismic scattered‐wave imaging. A fast‐moving detection device for urban construction conditions is designed to meet the data‐acquisition requirements on the basis of the scattered‐wave characteristics and equivalent offset migration method. Efficient acquisition and accurate detection are confirmed, with the detected depth deviating by less than 1 m compared to the depth obtained from borehole checks along the Xuzhou Metro Line 1 in China. The results show that cavity detection using seismic scattered waves can meet urban engineering requirements. Further study on the design of a high‐performance detection device, reception...