Abstract: BOTDA distributed optic fiber monitoring technology was used to monitor the deformation of pile and anchor supporting structure of deep foundation pit.Through long-term strain monitoring of H-steel and pre-stressed anchor of the supporting structure during the excavation process,the deflection distribution of H-steel and stress distribution of pre-stressed anchor were obtained.On this basis,the stress and deformation state of H-steel and pre-stressed anchor was analyzed,providing reliable reference for pit construction.Engineering practice shows that deformation monitoring for foundation pit's supporting structure using distributed optical fiber sensing technology based on BOTDA is feasible and has the advantage of continuous monitoring.

Key words: deep foundation pit support, ESC-H steel piles, pre-stressed anchor, BOTDA, deformation monitoring