地震CT技术在城市地质勘察中的应用研究

The Application of Seismic CT Technology in Urban Geological Survey

本文通过应用地震层析成像(CT)技术,对跨孔成像法采集得到的初至波走时,用基于最短路径法的弯曲射线追踪正演和基于LSQR算法的反演技术进行处理。与测井资料联合解释,得到井间波速分布图,对井控范围内的地层构造和地基注浆效果进行了研究,最终得到断裂构造带和人防空洞的分布。认为地震CT在进行城市环境地质调查与评价、浅层工程地质勘察时,能够解决地层岩性和构造的复杂性,对目标环境进行准确预测,在城市环境地质研究和基础设施建设中起重要作用,对促进城市地球物理勘察技术的发展有重要意义。

In order to successfully apply seismic computerized tomography （CT）, at first, the author used cross-hole imaging method to get the first break travel time data. Then, on the processing basis of curved ray-tracing forward modeling based on shortest path method and inversion technique based on LSQR algorithm, combined with well logging data interpretation, the author got the cross-hole wave velocity distribution maps. Thus, within the scope of well control, the stratum structure and the foundation grouting effect were studied. Also, the locations and distributions of fracture tectonic belt and people shelter were gotten. This result shows that when seismic CT is used in urban environmental geological survey and evaluation and shallow engineering geological investigation, it can solve the complexity of formation lithology and structure and accurately predict the target environment. Seismic CT plays an important role in urban environmental geology research and in the construction of infrastructure and has important significance to promote the development of urban geophysical prospecting technique.