利用钻孔雷达探测煤矿井下顶底板界面的数值模拟研究  

Numerical simulation research on detecting underground coal mine roof and floor using borehole radar

作　　者：刘四新[1] 宋梓豪 程建远 蒋必辞 LIU Si-xin;SONG Zi-hao;CHENG Jian-yuan;JIANG Bi-ci(College of Geo-exploration Science and Technology,Jilin University,Changchun 130026,China;Xi an Research Institute of China Coal Technology&Engineering Group,Xi an 710000,China)

机构地区：[1]吉林大学地球探测科学与技术学院,长春130026 [2]中煤科工集团西安研究院有限公司,西安710000

出　　处：《世界地质》2021年第3期711-720,共10页World Geology

基　　金：国家自然基金项目(41874136、42074146)。

摘　　要：为了更好地在实际生产中识别煤层顶底板位置和对采掘有威胁的地质构造,验证钻孔雷达在煤矿井下探测的有效性,笔者根据时间域有限差分原理,基于gprMax2D软件对煤矿井下钻孔雷达数据进行了模拟。建立了多频多煤层厚度的水平钻孔模型、多倾角下的倾斜钻孔模型、正断层模型、裂隙带模型、陷落柱模型和夹矸模型并得到相应数值模拟结果。结果表明,钻孔雷达能够识别顶底板位置并有效发现异常地质体;雷达中心频率在50~600 MHz时能够得到较好的探测结果且分辨率随频率升高而升高;斜钻孔对于顶底板识别影响较小;断层、裂隙带、陷落柱和夹矸等在数值结果中显示出了各自的特点,这些特点在实际生产中可为雷达剖面解释提供参照。总体上看,利用钻孔雷达对煤矿井下顶底板界面和特殊构造进行探测是可行的。In order to identify the position of coal seam roof or floor,find geological structures which are threatening to mine in actual production and verify the effectiveness of borehole radar in underground detection of coal mines,the authors use gprMax2D which is based on the finite difference time domain(FDTD)method to simulate borehole radar data.Horizontal borehole model with different frequencies under different coal thicknesses,slanted borehole different dip angles,faults,fracture zones,collapse columns and dirt bands models were built and corresponding simulating results were obtained.The results show that borehole radar can identify the position of the roof and floor,and find the abnormal geological structures effectively.When the center frequency of the radar is from 50 MHz to 600 MHz,better detection results will be obtained.The resolution increases with the increase of the frequency.Slanted borehole has little influence on the identification of roof and floor.Faults,fracture zones,collapsed columns and dirt bands have shown their own characteristics in simulating results.These characteristics provide references for the interpretation of the radar profile in actual production.In summary,it is feasible to use borehole radar to identify the position of coal seam roof or floor and find the abnormal geological structures.

关 键 词：钻孔雷达 数值模拟 煤层顶底板 时间域有限差分 

分 类 号：P631.3[天文地球—地质矿产勘探] TD823[天文地球—地质学]