Wireless sensor technology monitoring a tunnel structure

Monitoring that secures the tunnel drive.

Convergence in the cross-section, settlement above the drive, vibration and existing structures in the zone of influence: we monitor the decisive parameters wirelessly, in line with standards and with automatic alerting, entirely without mains power.

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Benefits in tunnel construction

Your benefit as a tunnel contractor, engineer or operator

Whether tunnel boring, refurbishment during operation or building within existing infrastructure: continuous monitoring lowers your risk, creates evidence, and lets you react immediately to critical movements.

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Detect risks early

Convergence, settlement and vibration are captured continuously. You see critical developments before they turn into damage, not only at the next scheduled inspection.

Protect existing structures

Buildings, utility lines and structures within the zone of influence of the drive are monitored objectively. This protects third parties and removes the basis for later damage disputes.

Evidence that holds up

We assess vibration against the guidance values of DIN 4150-3. All readings come together as a seamless time series and are verifiable towards building authorities, operators and experts.

Without mains power, without cable trenches

The wireless sensor technology works self-sufficiently and is installed without running cables. That is a decisive advantage in a confined tunnel cross-section and under ongoing traffic.

Live scenario

See what the drive moves, immediately

The cross-section shows where we measure: convergence in the excavation, settlement above the drive and vibration at the existing structure. Start the scenario and watch how the readings approach the thresholds.

Vibration Convergence Settlement Tunnel boring

Schematic illustration, not measured data

Convergence

Stable

Deformation of the excavation

0.0 mm

Threshold 5.0 mm

Settlement

Stable

Ground above the drive

0.0 mm

Threshold 8.0 mm

Vibration

Stable

Peak particle velocity v

0.0 mm/s

Threshold 5.0 mm/s

When a threshold is reached, the system alerts automatically by email and SMS.

What we monitor

The decisive parameters in tunnel construction

From convergence in the excavation to settlement and vibration to cracks and corrosion at existing structures, each measuring task with the matching sensor technology.

Deformation sensor for convergence measurement in the tunnel cross-section

Deformation in the excavation

Convergence measurement in the tunnel cross-section

We continuously capture the deformation of the excavation cross-section. Changes in clear width and height indicate how the ground and the lining are settling, and provide the data basis for safe tunnel-boring decisions.

To tilt & settlement monitoring
Baseline measurement and settlement monitoring at the ground surface above a tunnel drive

Above the drive

Settlement monitoring at the ground surface

Above the tunnel-boring axis we monitor settlement of ground and buildings. This keeps the settlement trough in view at all times, and lets you steer the drive before thresholds are reached at sensitive structures.

Monitor settlement & tilt
Sensor technology for construction vibration monitoring in tunnel construction to DIN 4150-3

DIN 4150-3

Vibration from blasting and tunnel boring

Blasting, milling and heavy construction machinery generate vibration. We measure the peak particle velocity and assess it against the guidance values of DIN 4150-3, the German standard for vibration effects on structures, so that adjacent buildings are evaluated safely and in line with standards.

To construction vibration monitoring
Close-up of a crack sensor monitoring crack widths on an existing structure

Existing structures & portal

Cracks and corrosion on existing structures

At existing structures and in the portal area, we monitor crack widths to the millimetre as well as moisture and corrosion in the concrete. This accompanies refurbishments during ongoing operation and documents refurbishment success over long periods.

To crack monitoring

Everything from a single source

From the monitoring concept to ongoing operation

You do not coordinate separate trades. Concept, installation, maintenance and the ongoing monitoring come from a single point of contact, over the entire critical phase.

01

Concept

We define measured variables, thresholds and sensor positions, tailored to the tunnel-boring method, the structure and the relevant standards. On request, with ready-made positions for tendering.

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02

Installation

The wireless sensor technology is installed without mains power and without cable trenches, and commissioned with a documented baseline measurement, even under ongoing traffic.

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03

Maintenance and operation

We keep the system operational, replace sensors as needed and provide reliable data over the entire critical phase, as monitoring as a service.

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04

Monitoring and alerting

All readings come together around the clock. When defined thresholds are reached, the system alerts automatically, by email and SMS, without manual on-site inspection.

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From practice

Sensor-based monitoring during tunnel refurbishment on the A96

Reference from practice A96 motorway tunnel, Bavaria

Starting point

During operational retrofit works, the operators found chlorides in the portal area. The concrete walls had to be refurbished with the least possible removal and continuous observation of the residual risk.

Implementation

After staged removal of the chloride-affected layers, cable- and energy-free corrosion and moisture sensors of the CorroDec 2G type were installed at the positions specified by the engineer, including the portal area.

Result

The structure condition can be queried remotely at any time, via handheld reader and via NB-IoT. This reduces removal volumes and closure times, proves refurbishment success and steers inspection intervals precisely.

Two CorroDec 2G sensors, one with a red and one with a metallic housing, installed between reinforcement bars in the concrete

Goals achieved

  • Cable- and energy-free sensor technology in the structure
  • Remote query via NB-IoT and handheld reader
  • Compliant with repair principle "W"
  • Shorter closure times for later measures
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Matching sensors

This sensor technology is installed in the tunnel

Crack width, moisture, corrosion and convergence are the parameters in the tunnel. These are the devices behind them.

Infrasolute crack sensor solar, cut outProductsCrack sensorCrack width with 0.003 mm resolution, available as solar, long-life battery or mains power.CorroDec 2G moisture sensor with metal housing, cut outProductsMoisture sensor CorroDec 2GPassive RFID sensor for moisture directly in the concrete, energy-free and long-lasting.Corrosion sensor CorroDec 2G with red housing, cut outProductsCorrosion sensor CorroDec 2GTwo-stage wire monitoring in the concrete: shows whether the corrosion front has reached a defined depth.Tilt sensor for structural health monitoring, cut outProductsTilt sensorTilt and settlement of load-bearing components from 0.001°, gateway integrated.
All products

Monitoring for your tunnel structure

Whether tunnel boring, existing tube or structures in the zone of influence: tell us the situation. We align measuring points, thresholds and measurement interval with your project.

Request a quote To the tilt monitoring solution
Roman Koch Roman Koch

Data platform

All readings on one platform

The sensors transmit their readings wirelessly to the data platform, where they are evaluated, documented and continuously checked against your thresholds.

  • AI-assisted data analysis
  • User-focused reporting
  • Continuous evaluation
  • Warning and alarm thresholds
  • Alerts by email and text message
  • Remote access around the clock
More on monitoring & alerting
Monitoring platform Sample view
Reading history within limits
Warning threshold
  • AI-assisted data analysis Condition within limits
  • User-focused reporting Report ready
  • Alerting Thresholds monitored

Basis for decisions

What you can decide about the tunnel

In tunnel construction, every closure and every stop to the drive costs money immediately. Decisions are therefore made under time pressure and need reliable numbers.

  1. 01

    Continue or pause the drive

    Convergence and settlement measurements above the drive show whether the ground is behaving as expected. This carries the decision to adjust the lining or continue.

  2. 02

    Change the construction method in the zone of influence

    If vibration at existing buildings exceeds the guidance values, the method must be adjusted. Measured values clarify this before it turns into damage.

  3. 03

    Plan closures instead of improvising

    A tunnel cannot be closed at short notice. Whoever knows the condition development fits refurbishment into closure windows that are already planned.

  4. 04

    Prove refurbishment success

    After a refurbishment, measurement over years shows whether the measure is effective. That is the evidence towards the client and the warranty.

  5. 05

    Reduce site visits and manual measurements

    Measurements inside a tunnel tie up personnel and often require a closure. Self-sufficient sensor technology delivers the readings without anyone having to go in.

FAQ

Frequently asked questions about tunnel monitoring

Which measured variables are relevant in tunnel construction?
During tunnel boring, convergence and settlement are the main focus, complemented by vibration from blasting and construction machinery. At existing structures and in the portal area, crack widths as well as moisture and corrosion in the concrete are added. We tailor the measurement scope to the tunnel-boring method, the ground and the affected environment.
How are existing structures in the zone of influence monitored?
Buildings and structures above and next to the drive receive tilt, settlement and crack sensors. Before construction starts, we capture the baseline condition with a baseline measurement. All further readings are assessed against this, so movements are objectively verifiable and you are warned immediately at critical developments.
Which standards apply to vibration in tunnel construction?
We assess vibration on structures against the guidance values of DIN 4150-3, the German standard for vibration effects on structures. The permissible peak particle velocities depend on building type and frequency. We configure the thresholds on a project basis and document the readings in a verifiable form.
Does the sensor technology work during ongoing tunnel operation?
Yes. The sensors work wirelessly and are energy self-sufficient, entirely without mains power and without cable trenches. That is a clear advantage in a confined tunnel cross-section and under traffic. At the A96, the sensors were installed during a refurbishment under ongoing operation and are read out remotely.
Do I get concept, installation and operation from a single source?
Yes. From the concept of the measurement plan through the installation of the sensor technology to maintenance, operation and ongoing alerting, you get everything from one point of contact. You do not coordinate separate trades, but receive a complete solution.

Project inquiry

Secure your tunnel drive

Tell us about the structure, the tunnel-boring method and the affected environment. You will receive a reliable initial assessment shortly, including suitable measured variables and sensor technology.

+49 6742 8599600 DE +41 41 670 00 11 CH info@infrasolute.com
Project inquiry