Abstract: The application of the ground penetration radar (GPR) in the integrity of the tunnel liners has received more and recognitions by the tunnel practitioners. The accuracy in the GPR data interpretation is critical to the tunnel linear quality assurance.  This paper proposes the interpretation methods of the thickness of the liner, distribution of the steel frames and the density of the concrete. These methods are applied in the integrity check of a tunnel liner. The results are acceptable.

Key words: Ground Penetration Radar, Thickness of Concrete Liner, Steel Reinforcements, Steel Arch Support, Concrete Density