The use of Fibre Bragg Grating (FBG) sensors in geotechnical applications

Seccombe, Andrew James (2010) The use of Fibre Bragg Grating (FBG) sensors in geotechnical applications. [USQ Project]


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[Abstract]: Current ground monitoring systems have a number of significant faults that make the long-term monitoring of geotechnical environments unachievable. The long-term monitoring of geotechnical environments with current technology, such as electrical strain gauges, is limited by several factors, including, susceptibility to water ingress and corrosion; easily damaged by compaction, consolidation and dynamic loading; and negatively influenced by electromagnetic radiation (EMR) (Schmidt-Hattenberger et al. 2004).

The aim of this dissertation is to investigate the suitability and durability of Fibre Bragg Grating (FBG) sensors in geotechnical applications. To meet the requirements of the dissertation, a soil strain measuring device was designed and constructed to record the strains produced within a dynamic soilmass. By measuring the strain within a soilmass, it is possible to determine the
horizontal displacement of the soil by using elastic beam theory and moment-area theorems to analyse the recorded strains (Sato et al. 1999).

The experimentation section of this dissertation is sub-divided into two categories known as suitability testing and durability testing. The suitability testing will involve modelling the failure of a retaining wall structure and investigating whether FBG sensors are suitable to record the strains produced during the test. The durability testing will investigate the influence of moisture and electromagnetic interference (EMI) has on FBG sensors.

In conclusion, a FBG soil strain sensor was successfully designed, constructed and tested under laboratory conditions. In comparison to the conventional soil strain sensor, the FBG soil sensor accurately and reliably monitored ground movement. The results from the suitability testing show that FBG sensors are capable of measuring strains in a geotechnical environment. The FBG unit
also performed extremely well under the durability testing. The electromagnetic and corrosive environments that were simulated had no effect on the results of the FBG sensor.

However, more ‘real world’ and laboratory testing must be done before this technology can be fully integrated into ground monitoring systems. According to Schmidt-Hattenberger et al. (2003), the integration and application of FBG sensors in the geotechnical engineering will continue well into future.

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Item Type: USQ Project
Refereed: No
Item Status: Live Archive
Faculty/School / Institute/Centre: Historic - Faculty of Engineering and Surveying - Department of Agricultural, Civil and Environmental Engineering (Up to 30 Jun 2013)
Supervisors: Shiau, Jim; Epaarachchi, Jayantha
Date Deposited: 14 Mar 2011 01:55
Last Modified: 03 Jul 2013 00:33
Uncontrolled Keywords: FBG sensors; fibre Bragg grating sensor; soil strain sensor
Fields of Research (2008): 09 Engineering > 0905 Civil Engineering > 090501 Civil Geotechnical Engineering
Fields of Research (2020): 40 ENGINEERING > 4005 Civil engineering > 400502 Civil geotechnical engineering

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