复杂岩溶地区跨孔地震CT反演成像研究——以贵阳在建地铁3号线为例  

Inversion Imaging Research of Cross Hole Seismic CT in Complex Karst Areas:Guiyang Metro Line 3 under Construction Presented as an Example

作　　者：田占峰 裴世建 于强 TIAN Zhanfeng;PEI Shijian;YU Qiang(China Railway Liuyuan Group CO.,LTD.Engineering Survey Institute,Tianjin 300308)

机构地区：[1]中铁第六勘察设计院集团有限公司勘察院,天津300308

出　　处：《CT理论与应用研究（中英文）》2024年第5期561-567,共7页Computerized Tomography Theory and Applications

摘　　要：本文以贵阳在建地铁3号线为例,详细研究岩溶复杂地区勘察过程中跨孔地震CT技术的应用,揭露研究区岩溶发育特征。通过对不同算法的对比分析表明,相比于CGLS算法,LSQR算法对于低速异常的识别更灵敏和精确,具有更好的收敛性和可靠性。钻探验证表明,采用LSQR算法和弯曲射线追踪法进行地震层析成像反演,跨孔地震CT探测可达米级精度,获得满意的速度图像,能够查明钻孔之间岩溶埋深、规模、延伸等情况,弥补钻探的局限性,说明基于LSQR算法的地震CT技术探测岩溶是切实可行的。This article used Guiyang Metro Line 3 under construction as an example to study the application of cross hole seismic computed tomography(CT)technology in the exploration process of Karst complex areas,thereby revealing the characteristics of Karst development in the study area.Through comparative analysis of various algorithms,it was determined that compared to the conjugate gradient least squares(CGLS)algorithm,the sparse linear equations and least square problems(LSQR)algorithm is more sensitive and accurate in identifying low-speed anomalies,and has better convergence and reliability.Drilling verification shows that using the LSQR algorithm and bending ray tracing method for seismic tomography inversion can achieve meter level accuracy in cross hole seismic CT detection,obtain high-quality velocity images,and identify the depth,scale,and extension of Karst between boreholes,neutralizing the limitations of drilling.This indicates that seismic CT technology based on the LSQR algorithm is practical and feasible for detecting Karst.

关 键 词：地震CT技术 LSQR算法 波速 钻探 岩溶勘察 

分 类 号：P315[天文地球—地震学] P631.4[天文地球—固体地球物理学]