GPR detection of several common subsurface voids inside dikes and dams

Ground-penetrating radar (GPR) technique has been used in detecting several common subsurface voids inside dikes and dams in south of China, and the results indicate that GPR can be successfully applied to uncovering termite nests inside dikes and dams, and the technique proves to be advantageous in real-time retrieval of detection data, precise positioning and effect of application being basically not affected by locality and climate, when it is compared to other available methods. GPR is also effective in detecting cracks in the sloping clay core, and proves to pose less impact on the normal operation of the detected hydraulic projects, be more efficient, and capable of retrieving more comprehensive detection data, when compared with the method of artificial observation through holes chiseled out from the ground. Also, GPR is capable of detecting ferralsol in tropical and subtropical regions to some depth, and shows high value of application in detecting some hidden troubles such as caves and settlements with low to moderate depths inside dams in karst regions. Moreover, GPR technique proves to be so capable of detecting carbonate rocks to certain depth and can yield precise results that it can be applied to analysis and discovery of leakage channels inside reservoirs in karst regions. (C) 2009 Elsevier B.V. All rights reserved.