Abstract：Based on theoretical calculation，physical interpretation and practical testing data，the precision of inversion of shaft defect locations by peak-peak reflected wave testing curves for single piles is studied. The results indicate that the precision mainly depends on the ratio of the defect length to the critical defect length defined in this paper when the wave velocity in the piles is accurate. If the ratio is more than or equal to 1，the inversion defect locations are close to the true ones. If the ratio is less than 1，the inversion depth of the upper defect surface is shallower，while that of the lower defect surface is deeper. The inversion defect length for piles with short defect becomes larger than real one because of the superimposition of upward tensile wave reflected by the upper surface and upward compressive wave reflected by the lower surface，and this is verified by practical testing data.
