Application of distributed fiber optic sensing techniques in bored pile detection

The Brilliouin Optical Time Domain Reflectometer(BOTDR) was a new distributed optical-electronic sensing technique successfully developed abroad.It had been widely applied in detecting temperature,strain and stress of the structures.BOTDR was employed to detect the distribution of strain,side friction and tip resistance of the bored piles.The technology embedded on the sensing optical fiber was developed,a spectral processing method of BOTDR detection data was presented based on the wavelet analysis and moving average method,and the feasibility of using BOTDR to detect the bored piles was demonstrated through a practical engineering project.It was indicated that the BOTDR-based distributed detection technique for the bored piles was quite effective.Compared with the traditional point-mode monitoring techniques such as strain gauge and earth pressure cell,there were obvious advantages for BOTDR such as distributing,single-end detection,long-distance,durability,high survival rate,strong anti-interference and better coordination,and it was a very potential technique for the pile detection.