Research on the layout of optical fibers applied for determining the integrity of cast-in-situ piles

Distributed optical fiber temperature sensing technology has the potential to be used to determine the cast-in-situ pile integrity. This study proposed an arrangement of optical fibers for obtaining the pile integrity in situ, and it provided a calculation model for the temperature distribution. A model pile was constructed with the dimensions of 1.5 m × 0.5 m × 0.5 m. The fibers were implanted parallel to the center axis of the pile with a spacing of 0.04 m. The heat conduction area generated because of the heating of the fiber in the center of the pile was tested. The test results indicated that the heating conduction area was limited for certain heating powers. Furthermore, for the heating conduction area and heating power, care must be taken while arranging the optical fibers in the piles to determine the integrity.