跨孔电磁波层析成像探测技术在桥梁主墩基础岩溶勘察中的应用  

Application of Cross-hole Electromagnetic Wave Tomography Detection Technology in Karst Exploration of Bridge Main Pier Foundation

作　　者：廖顺 冯坤伟 李法滨[1] LIAO Shun;FENG Kunwei;LI Fabin(Guizhou Provincial Institute of Transportation Planning,Investigation and Design Co.,Ltd.,Guiyang 550009)

机构地区：[1]贵州省交通规划勘察设计研究院股份有限公司,贵阳550009

出　　处：《公路交通技术》2020年第3期49-54,共6页Technology of Highway and Transport

摘　　要：为查明贵州省贵安新区黔中大道某特大桥主墩区域的岩溶分布情况,采用跨孔电磁波层析成像探测技术,获取电磁波在孔间地层传播过程中的时间剖面,通过拾取电磁波的初至时间,反演获得地层的速度场和衰减系数场,对比电磁波在不同介质中的特征,可推断岩溶异常区。探测结果表明:1)电磁波在岩溶区的速度与衰减系数和围岩有密切关系,据此能分辨出岩溶的发育情况;2)采样间距与分辨率成反比关系;3)孔间距是影响探测效果的重要因素;4)后期钻探验证了与本次跨孔电磁波层析成像探测结果的一致性。In order to find out the karst distribution in the main pier area of a super-large bridge on Qianzhong Avenue in Guian New District,Guizhou Province,the cross-hole electromagnetic wave tomography detection technology is adopted to obtain the time profile of electromagnetic wave propagation in the inter-hole strata.By picking up the first arrival time of electromagnetic wave,the velocity field and attenuation coefficient field of the strata are obtained by inversion,and the karst anomaly area can be inferred by comparing the characteristics of electromagnetic wave in different media.The detection results show that:1)The velocity and attenuation coefficient of electromagnetic wave in karst region have significant changes with surrounding rock,thus the karst development can be distinguished;2)Sample spacing is inversely proportional to resolution;3)Hole spacing is an important factor affecting the detection effect;4)Late drilling verified the consistency with the detection results of this cross-hole electromagnetic wave tomography.

关 键 词：跨孔电磁波层析成像 岩溶 特大桥 波速 衰减系数 

分 类 号：U443.22[建筑科学—桥梁与隧道工程]