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  • Photo of the Istanbul Metro Tunnel.


    Many tunnels and subway systems in major cities around the world have used GEOKON instruments. GEOKON is a specialist in the supply of instruments for the NATM method of tunnel support. In addition to almost all major cities in the USA, we have instrumented subway systems in Seoul, Taipei, Guangzhou, Istanbul, Hong Kong, Singapore and London. We also have instruments in the Channel Tunnel.

    Learn more about our tunnel monitoring, data collection and long-term reliability

Case Histories

  • Photo of the Tesalia Tunnel entrance portal.
    Photo of a Model 1100 Rod Type Borehole Extensometer installation.

    Tesalia Tunnel

    Caldas, departamento, Colombia

    The Tesalia Tunnel project, located in Colombia, has a length of 3.5 km and facilitates connectivity to the country’s main production centers.

    The slope stability of the tunnel entrance portals are monitored using Model 1100 Rod Type Borehole Extensometers, with Groutable Anchors, and Model 4450 Displacement Transducers. Instrumentation was installed in 2018 for monitoring the tunnel during construction and operation phases.

    For additional information, please contact: Francisco Ordoñez | Ingenieria Tecnologia e instrumentacion S.A.

  • Photo of Blackfriars Station Redevelopment Project.Photo of Tilt Beam installation.

    Blackfriars Station Redevelopment Project

    London, England, United Kingdom

    An extensive instrumentation system has been installed at the Blackfriars Station in London to monitor the station, rail tracks and surrounding buildings as the underground part of the old station is demolished and a new station constructed.

    Instrumentation included Automated Total Stations, Accelerometers, CrackmetersTilt Beams and Strain Gauges.

    For additional information, please contact:  | Strainstall UK Ltd.

  • Photo of Chaira Pumped Storage Power Plant.Layout of instruments around Headrace Tunnel No. 2.Layout of instruments around Penstock Tunnel No. 2.

    Chaira Pumped Storage Power Plant (CPSPP)-II

    Southwest Bulgaria

    The hydroelectric complex of the Chaira Pumped Storage Hydroelectric Power Station is situated in the northern part of the Rila Mountains in southwest Bulgaria. It consists of the Belmeken and Chaira Dams and the Headrace and Penstock Tunnels between them.

    During the summer of 1997, instrumentation was installed to monitor the behavior of the Headrace and Penstock Tunnels during filling and operation. The instrumentation around the Headrace Tunnel No. 2 consisted of vibrating wire Piezometers installed both in the concrete lining and in the surrounding rock.

    The instrumentation in the Penstock Tunnels consisted of vibrating wire Strain Gauges to measure stress in the concrete and Embedment Jointmeters to measure any detachment of the concrete from the steel liner. Readings were taken and recorded using the GK-403 Vibrating Wire Readout Box.

    For additional information, please contact: Petko Slavov

  • Photo of Inclinometer installation.Photo of Load Cell installation.

    Busan Subway 308

    Busan, Korea

    A comprehensive instrumentation system comprising TiltmetersInclinometersExtensometersTape ExtensometersStrain Gauges and Load Cells was installed to monitor the safety and stability of subway (section 308) in Busan, Korea.

    For additional information, please contact:

    Young Eok, Kwon | Heung-In E & I Co., Ltd.

  • Photo of FCC (Line 7) Subway.

    FCC (Line 7)

    Madrid, Spain

    The construction of the FCC (Line 7) subway in Madrid used a combination of both cut and cover and TBM excavation methods.

    The retaining walls, supporting the cut and cover excavation, were instrumented with Strain Gauges, InclinometersPressure Cells and Piezometers.

    Tunnel sections were instrumented with Concrete Stress Cells.

    For additional information, please contact: Javier Andreu | Ingeneria de Instrumentacion Y Control

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