城市浅层地下空间结构小回线瞬变电磁RDI-SA高分辨反演成像方法  

High-resolution inversion imaging method for urban shallow subsurface structures using small-loop transient electromagnetic RDI-SA

作　　者：刘又嘉 卞雷祥[1] 徐展 胡杰[1] 何勇[1] 王明洋 LIU Youjia;BIAN Leixiang;XU Zhan;HU Jie;HE Yong;WANG Mingyang(Nanjing University of Science and Technology,Nanjing 210094,China;Army Engineering University of PLA,Nanjing 210007,China)

机构地区：[1]南京理工大学,江苏南京210094 [2]陆军工程大学,江苏南京210007

出　　处：《防护工程》2024年第1期54-61,共8页Protective Engineering

基　　金：国家自然科学基金资助项目(61973165);江苏省卓越博士后计划资助项目(20220ZB239)

摘　　要：小回线瞬变电磁探测系统关断时间短、发射线圈面积小,有对地探测盲区小、横向分辨率高等优点。城市浅层地下空间结构相对于自然资源勘探对象具有尺度小、形状多变、物性参数与背景参数差异大等特点,反演计算时求解空间范围大,多解性和收敛性问题突出。提出一种视电阻率深度成像(resistivity depth imaging, RDI)-模拟退火(simulated annealing, SA)联合反演方法,利用瞬变电磁数据进行视电阻率深度成像,根据成像结果限定待求解模型参数的范围,指导模拟退火算法初始状态的确定,并构成参数更新过程的上下边界,对SA反演过程进行改进与优化。选取浅埋市政交通隧道和人防洞室2种典型的城市地下空间结构,利用自研小回线瞬变电磁探测系统开展实例探测分析,结果表明:上述RDI-SA反演成像方法能够准确还原地下结构空间特征。The small-loop transient electromagnetic detection system has the advantages of short shutdown time and a small transmitting coil area,resulting in a small detection blind zone and high lateral resolution.Urban shallow subsurface structures,compared to natural resource exploration objects,have characteristics such as small scale,variable shapes,and significant differences in physical and background parameters.In the inversion calculation,solving a large spatial range leads to prominent problems of multi-solution and convergence.This study proposes a resistivity depth imaging(RDI)-simulated annealing(SA)combined inversion method.The transient electromagnetic data is used for resistivity depth imaging.The imaging results are utilized to constrain the range of the model parameters to be solved.This guides the determination of the initial state of the SA algorithm and forms the upper and lower bounds of the parameter updating process,improving and optimizing the SA inversion process.Two typical urban underground structures,shallow municipal transportation tunnels and civil air defense chambers,were selected.A small-loop transient electromagnetic detection system developed by ourselves was used for practical detection analysis.The results show that the RDI-SA inversion imaging method accurately restores the spatial characteristics of underground structures.

关 键 词：小回线瞬变电磁 视电阻率深度成像 SA优化算法 参数反演成像 

分 类 号：P631.325[天文地球—地质矿产勘探]