Application of Distributed Fibre Optic Cables in Piles

Abstract

A high spatial resolution distributed fibre optic sensing system for measuring strain and temperature was used to instrument fourteen single piles subjected to general subsidence. Thirteen piles were driven (six steel and seven precast concrete) and one was a cased continuous flight auger pile, CFA. The CFA pile was subjected to a static loading test. The distributed fibre optic analyser measured the spectral shift in the fibre Rayleigh scatter to obtain strain and temperature data. The seasonal temperature changes in the surficial soil layers showed to influence the strain records. Several lessons were learnt from the application of distributed fibre optic sensors in piles, such as installation methods, influence of temperature, and performance of fibre optic cables.