Tunnel Monitoring Using Wireless Sensors
Hourly measurements with a repeatability of ±50 µm. Data transmission via LTE-M and Wi-Fi, even in deep tunnels with limited cellular coverage.
Tunnel linings, segmental linings, and support shells are constantly deforming due to rock pressure, water ingress, convergence, and material fatigue. Manual convergence measurements require on-site inspections during normal operations, which in rail or road tunnels is only possible with extensive traffic control measures.
Between inspections, the structural behavior remains hidden. For critical structures, this poses a risk that would need to be continuously monitored; in practice, however, it is often not monitored because the effort involved is too great.
The reference object and sensor are each secured to the tunnel segment, the support shell, or the inside of the tunnel with two screws. No special tools are required, and there is no need to alter the supporting structure. The sensor can be installed in just a few minutes and begins transmitting as soon as it is activated.
The XT 3D sensor takes hourly measurements in three spatial axes and transmits the data to our data hub via LTE-M or Wi-Fi. Even when cellular reception is limited inside the tunnel, data transmission continues via the internal Wi-Fi network or a gateway at the tunnel portal.
Multiple sensors positioned along the tunnel axis reconstruct the deformation profile over the entire length of the tunnel. Changes are displayed in the data hub as a time series. If a threshold is exceeded, our system automatically sends an email notification.
There is a sensor to suit every measurement point and motion pattern.
The leading solution for tunnel monitoring. Hourly measurement intervals over a ten-year period, even at measurement points without regular maintenance access, thanks to an external battery box.
When rotation must be measured in addition to translation, such as in tunnel linings or portal structures prone to settlement and tilting.
Specific differences compared to manual convergence measurement and conventional tunnel inspection.
The XT 3D sensor takes hourly measurements via the external battery box, eliminating the need for maintenance on the sensor itself. At measurement points that would otherwise only be accessible by foot or with a lift, the sensor provides continuous measurements throughout the entire project duration.
LTE-M and Wi-Fi in parallel. When cellular reception is limited, the sensor uses the tunnel’s internal Wi-Fi network or a gateway at the tunnel portal. Data reaches the data hub even from deep within the tunnel.
Multiple sensors placed along the length of the tunnel reconstruct the overall deformation behavior. Anomalies at individual measurement points can be evaluated in their spatial context rather than in isolation.
Manual convergence measurements require inspections to be conducted while traffic is moving. Wireless sensors provide data continuously, without the need for road closures or personnel in the tunnel.
Tunnel monitoring projects using our sensors.
Real-time structural monitoring following a tunnel fire to enable rapid reopening during ongoing restoration work.
Wireless 3D measurement of concrete segments in tunnel construction.
Continuous monitoring of structural movements in the historic reception building during the critical construction phase
High-precision building monitoring of settlement and crack development to assess damage caused by subway construction work.
Monitoring of bearing and abutment movements and structure temperature during operation.
“Following a tunnel fire, the 3D sensors from SuessCo Sensors FlexCo were deployed to monitor the affected tunnel arch segments. Continuous monitoring made it possible to maintain temporary operations until final repairs could be completed. As part of the safety management plan, alarm thresholds were defined, and a specific group of people would have been notified via email and SMS if the alarm threshold was reached. The system stands out for its precise measurements and the wireless remote transmission of data to a portal that experts can access at any time without disrupting operations.”
Reinhold Czizsek, Engineer
Asset Management, ASFINAG Bau Management GmbH
“Our collaboration with SuessCo Sensors has always been professional and solution-oriented. For expert assessments, the continuous measurement data from the SuessCo sensors is a major advantage, as changes can be objectively documented and reliably evaluated." "With the XT 3D sensors, we receive precise and stable measurement data wirelessly in three dimensions. This enables reliable remote monitoring of sensitive tunnel areas and significantly reduces our on-site workload."
Mohammed Ismail
Geomatics Engineer, TABERG Engineering and Consulting Firm, LLC
"Thanks to the high-precision sensors from SuessCo Sensors, we have been able to continuously monitor changes in the Palm House. This data helps us protect this wonderful building and its historic structure."
Helmut Heninger, B.S. in Engineering
Austrian Castle Administration
"SuessCo's sensors have proven to be extremely precise and easy to install. What is particularly impressive is that they withstood the extreme conditions of the Swedish winter without any problems. Our collaboration with SuessCo has always been reliable and professional."
Paul Collins
Sales Manager, GEOFIX Sweden
"With the SuessCo 6D sensors, we always have up-to-date measurements available. This naturally saves us money and improves quality."
Georg Gotthart
Plant Technician, Bridge Construction, ÖBB
The XT 3D sensor is the primary solution for tunnels. The external battery box enables hourly measurements over a period of ten years, which is crucial for hard-to-reach measurement points in tunnels. If tilt or rotation also needs to be measured—for example, at tunnel linings or portal structures—the 6D sensor complements the measurement points.
The sensor transmits data via LTE-M and Wi-Fi. When cellular reception is limited, it uses the tunnel’s internal Wi-Fi network or a gateway at the tunnel portal. Data reaches the data hub even from deep within the tunnel where there is no direct cellular coverage.
Several sensors are mounted along the tunnel axis on the tunnel segments, the supporting shell, or the tunnel lining. Each sensor measures movement at its specific location; together, they reconstruct the deformation profile along the entire length of the tunnel. The data is analyzed in the data hub as a time series.
Yes. Installation on the tunnel segment or the supporting shell does not require a complete closure of the tunnel. Maintenance windows or a one-way closure are usually sufficient. Once secured with two screws and activated, the sensor is immediately ready for operation.
The XT 3D sensor with an external battery box provides hourly measurements for ten years without requiring any maintenance on the sensor itself. No battery replacement is necessary within typical tunnel inspection intervals.
All measurement values are available in the Datahub as a CSV export. You can use the deformation profile as a data basis for regular tunnel inspections or to detect anomalies early on between inspection intervals. The API enables integration into existing tunnel monitoring systems.
