Abstract:

Retaining pile is a key part of bracing and retaining structures which directly affect the stability of deep foundation pit.
Therefore, it is important to monitor the strain and stress state of a retaining pile. In this paper, the single-ended detecting distributed optical fiber sensing technology based on the Brillouin Optical Time-Domain Reflectometer (BOTDR) was used for monitoring the deformation of a PHC type retaining pile in a deep foundation pit. The monitoring method was described and its effectiveness was well verified in a deep foundation pit in Nanjing. The results indicate that the BOTDR-based method is feasible to make a fully-distributed monitoring of the retaining pile in the deep foundation pit. It is expected to be a novel way for monitoring deep foundation pit.

Key words: Retaining pile, distributed fiber optical sensing (DFOS), deep foundation pit, BOTDR, monitoring method