A single-sensor system for length estimation of unknown piles using guided waves

Abstract

The practice of reusing unknown foundations in construction projects involves using existing foundations, even though there may be limited knowledge about their geometric and physical characteristics, conditions, and stability of the soil layer and the buried structure. Accurately estimating the pile length is a critical aspect of this practice. In this study, we introduce a new pile length estimation method based on guided wave theory and utilizing only one sensor for data collection. The objective is to enhance operational flexibility in the characterization of unknown piles, in terms of data acquisition, sensor placement, and accuracy in pile length estimation. The sensor can be positioned either on the lateral side of the pile or on its top surface. The recorded responses in the frequency domain are analyzed, and their normalized magnitude is calculated. Using the dispersion relation determined by the guided wave model, we obtain the dispersion analysis diagram of the wavenumber as a function of the normalized magnitude of the recorded response. By performing periodic analysis of the dispersion analysis diagram, the pile length can be estimated. Our proposed method has been verified using both synthetic and experimental data. The results demonstrate the efficacy and accuracy of the proposed method.