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Imaging characteristics and interpretation for karst caves using electrical resistivity tomography(PDF)

长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]

Issue:
2018年05期
Page:
221-230
Research Field:
交通工程
Publishing date:

Info

Title:
Imaging characteristics and interpretation for karst caves using electrical resistivity tomography
Author(s):
WEI Feng1; 2;  CHEN Zhongda1;  ZHANG Zhen1;  ZHU Yaoting3;  HU Wenhua4;  WU Fuquan4
Keywords:
traffic information and control engineering;  karst cave;  electrical resistivity;  imaging characteristic;  resistance shielding;  explain
PACS:
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DOI:
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Abstract:
To study the imaging characteristics of a cave using electrical resistivity tomography, the resistivity characteristics of karst strata along the Nanchang to Shangli Highway (Jiangxi, China) were investigated. Corresponding numerical models were established for forward modeling. In the karst caves that were identified, longspan empty caverns, longspan filled caverns, shortspan empty caverns, and shortspan filled caverns were selected for observation. The imaging characteristics of caves with different sizes and fillings were then obtained. A tree diagram for the analysis of the imaging characteristics of karst caves was proposed. The existence of highresistance and lowresistance media in homogeneous spaces was simulated and then compared with survey results. Finally, the imaging feature analysis tree diagram of the karst cave was applied to engineering practice for interpretation of resistivity tomography images. At the same time, the correctness of the method was verified by drilling results. The results show that both highresistivity and lowresistivity anomalies exist mainly in the longspan empty caves and longspan filled caves, rather than in the shortspan empty caves and shortspan filled caves. Contour line bending always exists in the filled karst cave and is often accompanied by lowresistivity anomalies. The contours gather in the lowresistance medium, which bends the contour lines. At the same time, owing to gathering of these resistivity contours near lowresistivity media, the extension of which is greatly limited, resulting in lowresistivity shielding effects. In shortspan caverns, owing to the lowresistance screening effect, highresistance media such as shortspan empty caverns or thinner cavern roofs are often covered, which makes it difficult to explain. 10 figs, 25 refs.

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Last Update: 2018-10-23