Abstract: The brilliouin optical time domain analyzer (BOTDA) is a new distributed optical-electronic sensing technique successfully developed abroad. It had been widely applied to detecting temperature and strain of structures. The new distributed strain measuring technique, pulse-prepump-brilliouin optical time domain analyzer (PPP-BOTDA) method realizes the test results of 10cm spatial resolution and ±7.5 με strain measuring precision. This paper describes the basic principle and experimental results of PPP-BOTDA, And its strain measuring method has been firstly applied to the tubular pile test; at the same time, a contrast with the sliding micrometer results is done; and it is shown the PPP-BOTDA is a very potential technique for the pile test.

Key words: pulse-prepump-brilliouin optical time domain analyzer, spatial resolution, tubular pile test