An optimization algorithm for ultrasonic tomography of foundation pile based on three-dimensional space path tracking is addressed in this paper. This algorithm can overcome the limitations of 3D tomography technology and traditional sonic logging techniques for piles testing and the shortcomings. By optimizing the distribution of spatial field source points, the Dijkstra algorithm is used to accurately track the elastic wave propagation path in three-dimensional space. And combined with the improved SIRT algorithm, the visualization of the internal structure of concrete foundation piles and the rapid location and quantitative assessment of potential defects are achieved. Subsequently, numerical simulation verification was carried out through the finite element analysis software ABAQUS. The impact of key technical parameters including transducer arrangement density, field source point encryption coefficient and defect characteristics on the three-dimensional tomography results was analyzed. Finally, the proposed optimization algorithm was applied to a bridge pile foundation on the Qiantang River in Hangzhou City, Zhejiang Province. The results demonstrate that the technology can accurately locate concrete defects and provide references for defect types and severity, offering theoretical and technical support for innovations in sonic logging methods for piles testing.

pile foundation detection  /  reinforced concrete piles  /  tomography  /  three-dimensional path tracking  /  ultrasonic transmission