煤田地质与勘探2023，Vol.51Issue(12)：157-166,10.DOI:10.12363/issn.1001-1986.23.05.0287
等值反磁通瞬变电磁和微动勘探在浅部岩溶探测中的应用
The application of the opposing coils transient electromagnetic method and microtremor survey method in shallow karst detection
摘要
Abstract
Concealed karsts frequently lead to disasters such as ground collapse,water reservoir seepage,and tunnel wa-ter inrush.Identifying the distribution and development of karsts in advance holds great significance for guiding engin-eering design and construction in karst areas.Geophysical methods rank among the most effective methods for karst de-tection.Given the problems of karst development,limited space,and serious electromagnetic interference in the tank farms of the Longkou Port,Shandong Province,this study explored shallow karsts in these farms through the joint ap-plication of the opposing coils transient electromagnetic(OCTEM)method and the microtremor survey method.Firstly,surface scanning was conducted with a grid density of 10 m×5 m using the OCTEM method.Based on this,3D geo-electric modes were constructed.Then,three short sections for microtremor surveys were supplemented above the karst developmental areas that were determined using inversion and interpretation,aiming to counteract the OCTEM method's inability to distinguish air-filled karst caves based on medium to high resistivity anomalies.The following results are ob-tained.The areas with low resistivity anomalies in the bedrock layer also exhibited low S-wave velocity anomalies.These two types of anomalies,which corresponded well,are inferred to be caused by karsts.Besides,there also existed some areas with low S-wave velocity anomalies in the bedrock layer that exhibited medium to high resistivity on res-istivity profiles.As verified by late drilling,these anomalies are caused by air-filled karsts.Based on the joint inference and interpretation using the two methods,the late drilling yielded a success rate of encountering karst caves of up to 70%,demonstrating the effectiveness of the combined detection methods The results of this study can be used to effect-ively solve the challenge of detecting shallow karsts in a complex environment,thus warranting wide promotion and ap-plication.关键词
岩溶探测/浅部/等值反磁通瞬变电磁法/微动勘探法/山东龙口港Key words
karst detection/shallow/opposing coils transient electromagnetic(OCTEM)method/microtremor survey method/Longkou Port of Shandong Province分类
地质学引用本文复制引用
张学亮,谢涛,周炜,高辉,邓冬,曲靖祎..等值反磁通瞬变电磁和微动勘探在浅部岩溶探测中的应用[J].煤田地质与勘探,2023,51(12):157-166,10.基金项目
中石化龙口液化天然气科技创新项目(2019-000052-45-02-000581) （2019-000052-45-02-000581）
