Conference Paper

Long term monitoring of reinforced earth structures using distributed fiber optic sensing

January 2015

Conference: Proceedings of the 7th International Conference on Structural Health Monitoring of Intelligent Infrastructure (SHMII)

Authors:

Graz University of Technology

Werner Lienhart

Graz University of Technology

Helmut Woschitz

Graz University of Technology

Hartmut Schuller

INSITU Geotechnik ZT GmbH

APLICAÇÃO DE NOVAS TECNOLOGIAS PARA AVALIAÇÃO DO DESEMPENHO DE TALUDES FERROVIÁRIOS EM REGIÃO TROPICAL

Conference Paper

Full-text available

Jan 2024

This article presents emerging technologies for inspection, monitoring, and analysis of slopes along the Carajás Railroad (EFC), developed within the research project of the VALE Under Rail Chair. A landslide susceptibility map using remote sensing data and monitoring by InSAR and LiDAR drones is utilized. Critical slopes are characterized and monitored with remote instrumentation, fiber optics, and low-cost sensors, following the methodology under development at GeoInfraUSP. The present and future behavior will be studied through numerical simulations considering the effect of vegetation, infiltration, and climate change. The methodology under development can be extended to other railways. Keywords: Inspection, Monitoring, Slopes, Railway, Climate Change.

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Presentation

Long term monitoring of reinforced earth structures using distributed fiber optic sensing

January 2015

Florian Moser

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Article

Full-text available

Distributed Fiber Optic Sensing Applications at the Semmering Base Tunnel

July 2020 · Proceedings of the Institution of Civil Engineers - Smart Infrastructure and Construction

The Semmering Base Tunnel in Austria is currently one of the largest tunnel construction sites in Central Europe. Two tunnel tubes, each 27.3 km long, are being built from the portal and three intermediate construction sites. Each access point poses specific challenges, and structural monitoring is a crucial element to ensure both economic and safe construction. In this paper, the authors ... [Show full abstract] describe one of the most comprehensive distributed fibre-optic sensing installations on a tunnel construction site worldwide. At the Semmering Base Tunnel, fibre-optic sensing is used at every construction location to monitor tunnel linings, shafts, reinforced earth structures and pipelines. The authors also discuss the challenges posed by the installations and the results of long-term monitoring programmes. The installed monitoring systems will, furthermore, be used throughout the expected 150-year operational lifetime of the tunnel. Unlike conventional sensors, fibre-optic sensors do not comprise electric or moveable components at the measurement location. A longer lifetime can, therefore, be expected for fibre-optic sensors, which makes them promising candidates for condition-based maintenance of civil infrastructure.

Article

Full-text available

Long-term monitoring of reinforced earth structures using distributed fiber optic sensing

July 2016 · Journal of Civil Structural Health Monitoring

Reinforced earth structures are commonly used to construct earth structures with high inclination angles. The stability and safety of such constructions is highly dependent on the strain distribution of the geogrids inside the earth structure. In this article, we report about the development and implementation of a structural monitoring system to measure the strain distribution of geogrids with ... [Show full abstract] high accuracy and high spatial resolution. The system was developed for the Semmering Base Tunnel project in Austria but can also be applied to other reinforced earth structures. The Semmering Base Tunnel is one of the core infrastructure projects in central Europe. Prior to the start of the actual tunnel excavation, comprehensive preparatory works in the alpine landscape were necessary. One of these works included the relocation of a river stream at the disposal site Longsgraben. To establish this relocation, a reinforced earth structure with a total length of more than 1.3 km and heights up to 25 m was constructed. To evaluate the stability of this structure, a monitoring system was developed. This monitoring system is thereby based on external geodetic and internal distributed fiber optic measurements. For the latter, about 2 km of Brillouin sensing cables in several sensor sections were installed in the project area. In this paper, we report about the laboratory experiments to determine strain and temperature coefficients for the conversion of the measured Brillouin frequency shifts into strain or temperature values. Furthermore, the long-term behavior of the monitoring structure is analyzed for the period of 1 year after installation.

Article

Reinforced earth structures at semmering base tunnel - Construction and monitoring using fiber optic...

January 2014

Reinforced earth structures are extensively used at the disposal site Longsgraben of the new Semmering base tunnel. These structures were monitored during construction using the observational method according to Eurocode 7. Geodetic measurements to targets on the surface of the structure were regularly performed in selected cross sections. However, surface deformations give only limited ... [Show full abstract] information about the operation grade of geogrids due to the inhomogeneous strain distribution within the object. We present a fiber optic measurement concept for the reliable measurement of strain of geogrids within earth structures. The monitoring system was specifically developed for the Semmering project and uses distributed fiber optic sensing based on Brillouin scattering. About 2km of sensing cables were installed in the project area. Unique anchors were designed to reliably transfer deformations of the geogrids to the sensing cables. The stability of the anchors was verified in detailed laboratory investigations. The measured Brillouin frequency shifts are converted into strain values using calibration functions derived from laboratory experiments. Finally the measured internal and external deformations are compared to predicted deformations from the finite element analyses. We demonstrate that with the developed monitoring system internal deformations can be measured reliably and with high precision.