Application of the opposing-coils transient electromagnetic method in urban geological surveys
HE Sheng1,2,3,4(), WANG Wan-Ping5, DONG Gao-Feng1,2, NAN Xiu-Jia3, WEI Feng-Feng3, BAI Yong-Yong3
1. Qinghai Bureau of Environmental Geology Exploration,Xining 810008,China 2. Key Laboratory of Environmental Geology of Qinghai Province,Xining 810008,China 3. Qinghai 906 Engineering Survey and Design Institute Co.,Ltd.,Xining 810007,China 4. Qinghai Institute of Geological Environment Survey,Xining 810008,China 5. Qinghai Provincial Land Remediation and Ecological Restoration Center,Xining 810008,China
With the rapid development of urban infrastructure,the demand for urban geological work is increasing,and urban geological surveys become particularly important.Urban geophysical exploration has different exploration purposes and working environments from conventional geophysical exploration.Accordingly,compared with conventional geophysical exploration methods,the geophysical exploration methods for urban geological surveys face the challenges of many interference factors,limited construction sites and time,and high requirements for exploration accuracy.The opposing-coils transient electromagnetic(OCTEM) method enjoys a strong anti-interference ability,convenient and efficient construction,and high resolution.Therefore,this study employed the OCTEM method to investigate the test profile in the urban geological survey and evaluation of Haidong City.This test profile was subjected to numerous interference sources since it crossed 11 highways and railways and passed through factories,schools,logistics parks,villages,living quarters,and rivers.Consequently,the OCTEM results agree well with the results of single-point resistivity sounding and drilling results.Therefore,the OCTEM method proposed in this study is effective for urban geological surveys.
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