Three reasons to include fiber optic sensing in your geotechnical monitoring toolkit.
In this webinar Nils Nöther from fibrisTerre and Christoph Monsberger from ACI Monitoring, Graz describe:
1. What distributed fiber optic sensing is
2. How to use it in tunnel monitoring
3. When to consider fiber optic sensing
SISTEMI INNOVATIVI DI MONITORAGGIO GEOTECNICO MEDIANTE SENSORI IN FIBRA OTTICA
Over the last 20 years, telecommunications engineering has developed a family of sensors based on optical fibres (Fibre Optic Sensors, FOS) that offer major advantages both in their mode of installation and data acquisition: they are competitive with traditional sensors, especially with a view to having systems that are able to withstand the test of time and be a pivotal element in the analysis of the state of efficiency of structures in the long term, i.e Structural Health Monitoring.
The day is organized by the University of Padua and is aimed at all technicians working in the field of monitoring, design and control of geotechnical and other structures.
It aims to be a moment to illustrate the potential of these sensors, their characteristics and possible applications, and finally to discuss the difficulties inherent in using these sensors.
The speakers, both national and international will present numerous successful and less successful applications of FOS, providing a broad overview.
Link to event (Italian)
La 11ème conférence nationale de géotechnique et de géologie de l’ingénieur (JNGG 2022) June 28-30
The conference features 150 presentations, with the theme of ‘Learning from the Past to Build the Future’
You will find a demo of the fibrisTerre fiber optic strain and temperature monitoring system on Dimione Systems’ stand (23), perfect for explaining the technique, and where we are curious to learn about your project.
Pile strain measurement
Ground movement detection
Tunnel lining deformation measurement
Continuous strain and temperature detection for long, large, and complex structures.
As we develop more underground spaces and insert deeper piles, what effect does excavation-induced ground movement have on nearby tunnels?
“Performance monitoring of a curved shield tunnel during adjacent excavations using a fiber optic nervous sensing system,” an article by Hong-Hu Zhu, De-Yang Wang, Bin Shi, Xing Wang, Guang-Qing Wei, describes how a fiber optic nervous system (FONS) based on Distributed Fiber Optic Sensing (DFOS) provided continuous monitoring of a curved tunnel during 22 months of adjacent deep excavations.The tunnel health condition was monitored both longitudinally and circumferentially for strain changes. Those changes are described and classified into Tunnel risk assessment grades, indicating one item to be immediately repaired and an area to be monitored closely.
This valuable insight into the deformation in the tunnel linings is used pragmatically in the tunnel’s management. The conclusions include a glimpse into what else could be monitored by FONS.
Standard Practice for Use of Distributed Optical Fiber Sensing Systems (DOFSS) for ©
ASTM F3079-14(2020)
Guidance, definitions, and good practice for instrumentation design, fiber selection is outlined.
Both embedded and surface-attached fiber optic strain sensor deployment are included.
“This practice specifically addresses the means and methods for the use of distributed optical fiber sensors for monitoring ground movements during tunnel and utility construction and its impact on existing utilities…”
ASME standard available for purchase
fibrisTerre is here to make it easy for you.
Bring us your questions regarding distributed fiber optic sensing for detecting strain during construction, so that we can help you plan the project.
fibrisTerre is presenting “Distributed Brillouin Strain and Temperature Sensing in Underground Structures” at the
EAGE Workshop on Distributed Fibre Optic Sensing, part of the Second EAGE Geoscience Technologies and Applications Conference, in London and online from 4-6 April 2022.
The conference will address “ the use of integrated geoscience solutions and technologies in a wide range of subsurface, reservoir and production challenges. EAGE GeoTech 2022 will bring together leading experts in geoscience, reservoir engineering, drilling and data science to tackle some of the major challenges facing the industry.”
“Workshop Overview:
Distributed fibre optic sensing technology has emerged as a powerful tool for continuous, high-temporal and spatial resolution mapping of the subsurface. The sensing technology is capable of high precision measurements of acoustic, strain and temperature energy distributions along the entire length of the optical fibre. This facilitates a cost-effective large-scale monitoring capability for a wide variety of novel subsurface applications over a single optical fibre installation. “
During the 10th International Conference on Structural Health Monitoring of Intelligent Infrastructure -June 30-July 2 (online)
Read more
“The International Day of Light (IDL) is an annual, global initiative that provides a focal point for the continued appreciation of light. IDL aims to raise awareness of the critical role light-based technologies play in our lives, elevating science, technology, art, and culture to help achieve the goals of UNESCO – education, equality, and peace.” (SPIE)
You can participate, for example, by entering the SPIE photographic competition
As photonics is at the core of our business, fibrisTerre is deeply appreciative of light in all its forms.
Read about fibrisTerre’s technology
Read the case study to find out how fiber optic strain and temperature sensing was deployed in a large earth retaining structure which formed part of a landfill construction.
Conventional geodetic techniques, a total station and bi-reflex targets measured the structure’s surface displacement. Fiber optic distributed sensing provided insight into the structure’s internal strain evolution. Thanks to an extended measurement campaign, when a strain event happened five years after the work began, the alarm was raised, indicating the area of strain.
The monitoring project integration was carried out by Engineering Geodesy and Measurement Systems, Graz University of Technology.
Looking to monitor a similar structure? Contact us
“Ageing structures and infrastructures in hazardous environment” was the theme for the International Society for Structural Health Monitoring of Intelligent Infrastructure workshop in 2021.
In the Geotechnics section, fibrisTerre presented:
“Distributed fiber-optic strain sensing: Field applications in pile foundations and concrete beams.”
