Performance monitoring of large rock-socketed piles by Brillouin fiber optic sensing

Fiber optic sensing technology is increasingly becoming a superior non-destructive means for the stress monitoring of civil engineering structures. To understand the mechanical properties of superlarge diameter rock-socketed piles under complicated geological conditions, field tests were performed by distributed fiber optic sensors. The feasibility of Brillouin fiber optic sensing technology in testing the compressive stress of piles had been tested by indoor model tests and its correlation coefficient had been acquired. The in-situ installation of the fiber optic sensors is carried out on the super large diameter rock-socketed piles of the Hezhang Bridge, Guizhou province, China. Based on the test data collection during construction, the data treatment and analysis, the bearing behaviors and load transfer mechanism were explored. The feasibility of the fiber optic sensing technology in monitoring pile stress was verified and its application was proposed. The results have reference value to pile theory and the application of fiber optic sensing technology on similar projects.