Distributive optical fiber detecting method and system for prefabricated pile damage

Abstract

The method sets up sensing optical fiber on surface of prefabricated foundation pile to be measured. Both dependent variable and temperature sensed of the fiber are based on Brillouin backscattering. At incidence end of pulsed light, the method measures received light power of Brillouin backscattering so as to accomplish function of measuring and positioning Brillouin frequency shift on each points of optical fiber. In procedure of sinking pile, strain distribution is as basic parameter to reflect impaired character and degree of foundation pile. Based on linear correlation between Brillouin frequency shift and strain, temperature, the method carries out temperature compensation based on measured strain distribution and temperature distribution so as to obtain actual strain distribution on surface of foundation pile to be measured.

Description

1. Technical field [0001] The invention belongs to the technical field of geotechnical engineering detection, and relates to a detection method and a detection system for prefabricated pile damage based on distributed optical fiber sensing technology. 2. Background technology [0002] Prefabricated piles are one of the commonly used forms of deep foundations in construction, transportation, water conservancy and other industries in my country. Usually, prefabricated piles need to be piled under pressure, which currently mainly includes two construction methods: hammering method and static pressure method. Due to the local stress concentration in the process of pressure pile penetration and the ubiquity of unfavorable geological conditions such as boulders, hard strata, soft and hard abrupt strata, etc., it often leads to foundation pile damage such as broken piles and local damage, which affects the pile foundation and superstructure. safety and durability. [0003] Existi...

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