The Application of Shortwave Band GPR in Investigation of Surrounding Rock-and-Lining Interface.

The Ground Penetrating Radar method is used to study a three-layered model of the surrounding rock–void–lining interface with regard to variation in the void thickness and in the electromagnetic properties of the void filler. The numerical modeling uses the method of finite differences in the time domain. The numerical modeling data are compared with the results of the physical simulation implemented using SIR-3000 GPR with the Model 52600 antenna having the working frequency of 2.6 GHz (S-band). It is found that the size of the void behind concrete lining and the electromagnetic properties of a material filling the void have influence on the accuracy of ranging to the lower boundary of the void and to the discontinuity in the form of a steel bolt located immediately behind the void in surrounding rock mass. [ABSTRACT FROM AUTHOR]