Interpretation of Reflectograms of Seismic Acoustic Flaw Detection of Piles

Abstract

The paper presents the results of continuity study of secant piles in excavated pits at microtunnelage by means of seismoacoustic flaw detection. The piles under study were placed in the work pits and the reception pits excavated for transfer of utilities of the urban networking infrastructure. The importance of the quality control is stipulated by safety assurance of the performance during utility re-routing. The piles provide for the important function of pit wall reinforcement against soil slides due to groundwater pressure. Reflectograms were provided of the auger-cast grout piles under study with subsequent analysis and confirmation of the design length and continuity of the pile trunk. The results of the test demonstrate a correlation of the soil uniformity with the signal regularity. On the interface of two soil layers of different density, the sound wave is reflected and partially passes further generating characteristic false defect peaks. The provided results are of practical value during reflectogram processing, allowing for experimental recognition of interferences and exclusion of flaws.