Distributed Monitoring of Sheet Piles in a Cofferdam Using Optical Frequency Domain Reflectometry Technology

Sheet piles play a crucial role in cofferdams, significantly influencing safety during excavation. The integration of optical frequency domain reflectometry (OFDR) technology enables sheet piles to autonomously monitor stress and deformation throughout the construction process. The feasibility of this method was demonstrated in an engineering case study. Furthermore, a layout approach was proposed for glass-carbon fiber composite-based optical cables, demonstrating its suitability for the distributed monitoring of sheet piles within cofferdams. The wavelet theory and optical smooth spline algorithm were used for data analysis. The findings indicated that the OFDR technology successfully captured the strain, bending moment, and deflection distribution on sheet piles during various excavation stages. These findings support the promotion of OFDR-based monitoring of sheet piles as an innovative cofferdam monitoring technology.