地质雷达数据介电常数递推反演研究

Recursive inversion research on dielectric permittivity with data by ground penetrating rader

地质雷达进行地质超前预报时,准确读取复杂地质环境下不均匀介质的介电常数是最为关键的环节。本文应用地质雷达天线在不同参数设置下进行采样,对采集到的数据进行分层研究,剖析对比各地层中电磁波传播速度,并对各地层的介电常数分布散点进行归纳。根据对地层开挖过程中的地质素描验证和岩性比对,确定了适合该区域的不均匀混合介质的等效介电常数。研究结果表明:应用现场试验归纳的区域等效介电常数值不同于试验室得到的绝对介电常数值,前者分布在一定的范围内。与现场岩性的介电常数值对比结果表明,本文方法可准确预测掌子面前方的岩性。

When the ground penetrating radar is used to carry out the advance geological forecast, to accurately take the permittivity of non-homogeneous dielectric under the complex geological environment is the most important key link. In this paper the GPR antenna is employed to take samples under the different parameter setups, and the sampled data are studied and analyzed in strata to contrast the electromagnetic wave transmission velocity in each stratum, and the scat- tered distribution points of the dielectric permittivity in each stratum are summarized. And the e- quivalent dielectric permittivity of non-homogeneous mixed mediums suitable for this region in terms of geological sketch validation and lithological comparison in the process of stratum excava- tion. The research results indicate that the regional equivalent dielectric permittivity values final- ized in the applied in-situ tests are different from those of absolute dielectric permittivity obtained from lab tests, whose values are distributed within a certain range. As contrasted with the in-situ lithological dielectric permittivity value, the results reveal that the method in this paper can accu- rately predict the lithology in front of tunnel face.