Worldsensing Tunnel Application - Monitoring Tunnel Convergence

How to perform tunnel convergence monitoring using Worldsensing Solution

1. Automatic convergence Measurement for NATM and TBM tunnels

2. Measurement of tunnel convergence is one of the most important controls of the NATM (New Austrian Tunneling Method) construction. Portable devices like tape extensometers , levels and temporarily installed total stations allow sporadic measurements. On the other hand, one of the most commonly used methods, the measuring tape , disrupts construction activities due to the use of aerial work platforms. Overview

3. Tunnel construction is constantly changing: Sequential excavation, initial support, permanent support... Top heading Bench

4. 4 LaserTilt90 Download Datasheet New Features Combined distance and tilt measurements A 3-in-1 laser distance meter, inclinometer and data logger New monitoring applications such as settlement measured from a reference point or to infer vertical settlement at the tunnel crown More flexible installation options with its ±90° range and 3-axis inclination measurement Provides data set average that can be used to filter noisy data

5. The original tender specifications stated that an accuracy of +/- 0.1mm is required. For measuring convergences the most important parameter is the repeatability, because what is from interest is the measurement of changes with the distance. The accuracy will be the error that would be on the absolute measurement, but as we are measuring with respect an initial reading, convergences could be measured with a similar accuracy than the repeatability (0,15 mm).

6. The LaserTilt90 may be easily relocated along the convergence cross sections up to the excavation front or until the measured relative displacements are stabilized when the required frequency of measurements is reduced. It can also be used when permanent monitoring is required.

7. LS-ACC-LAS-SB Swivel mounting bracket; attachment option: pole fixing 50 mm U-bolts, anchor rods or on a convergence bolt with 3/8” male thread. The swivel mounting bracket allows swivelling around the vertical axis (+/- 90°) and a minor rotation of the enclosure on the plate (+/- 3°). LaserTilt90 mounted on a swivel mounting bracket. The bracket is attached to a convergence bolt with ⅜” male thread. The set of bracket and LaserTilt90 can be easily relocated on a different convergence bolt.

8. NATM - Primary Reinforcement Phase Struss Radial anchored bolts Reinforced shotcrete

9. NATM - Primary Reinforcement Phase Monitoring Sections Multipoint Borehole Extensometers Pressure Cells Strain Gauges Load Cells on anchored bolts Prisms

10. NATM - Primary Reinforcement Phase Parameters Instrument Loadsensing Edge device Rock and soil deformation Multi-point borehole extensometers Vibrating wire 5-channel data logger Digital logger Stress in shotcrete tunnel linings Pressure cells Vibrating wire 5-channel data logger Analog 4-channel data logger Piconode 1-channel analog data logger Load in rock bolts Anchor load cells Vibrating wire 5-channel data logger Analog 4-channel data logger Piconode 1-channel analog data logger Pore water pressure on tunnel walls Piezometers Vibrating wire 5-channel and 1-channel data loggers Convergences Tape extensometer, robotic total stations, tiltmeters Laser distance meter wireless sensor

11. NATM - Primary Reinforcement Phase

12. NATM - Impermeabilization and Lining Phase Parameters Instrument Loadsensing Edge device Pore water pressure on tunnel walls Piezometers Vibrating wire 5-channel and 1-channel data loggers Temperature of concrete Thermistors Vibrating wire 5-channel data logger Analog 4-channel data logger Digital logger

13. Monitor tunnels efficiently with IoT technology TBM TUNNEL MONITORING Structural health of tunnel lining The prefabricated concrete segments constitute the lining support in most of the tunnels made by tunnel boring machines. Monitor the health status of these critical elements using IoT instrumentation embedded in the structure. Tunnel convergence A key control parameter in tunnels is their convergence. It monitors the stability of the tunnel remotely and unattended through intelligent IoT instrumentation, which is capable of adapting to service hours so as not to cause any damage.

14. Use the Worldsensing 3-in-1 Laser Inclinometer in cases where tunnel convergence measurement cannot be performed via standard surveying approaches due to site limitations. The Laser Tilt90 is a wireless laser distance meter, inclinometer and data logger. It measures convergence using laser distance measurements in combination with angular displacement readings from the inclinometer. It transmits all data through a long-range LoRa network. Accurately evaluate tunnel convergence data. Possibility of reading distances on surfaces without using laser targets. 14 Tunnel Convergence TUNNEL MONITORING

15. Instruments inside tunnel structure (TBM section) P ressure cells Strain gauges Laser tiltmeter

16. Design of Tunnel Convergence Lines Different designs with a different number of convergence lines are posssible . It is important to consider the excavation sequence and validate the proposed convergence measurement with the engineering team responsible for the tunnel design.

17. Long-range inside the tunnel 17 VW-RCR, Tilt90 Laser Gateway inside TBM Up to 3 km* Gateway on Tunnel Lining Up to 800 m With TBM interferences THIRD-PARTY SOFTWARE INTEGRATION OPTIONS: MODBUS, HTTP API CALLS, MQTT & FTP PUSH Gateway on manufacturing premises Worldsensing's LoRa network enables remote management of devices within the tunnel over long distances. Through the CMT platform, you can visualize all your connected devices and integrate this information with your data visualization system. TUNNEL MONITORING

18. SOLUTION Vibrating Wire Data Logger RCR Ultra-robust 5-channel data logger suited to be embedded in concrete segments for tunnel linings. Connect vibrating wire instruments easily and securely such as: Strain gauges, pressure cells, Any other vibrating wire sensor. Monitor tunnel lining integrity from as early as the concrete segment manufacturing stage. 18

19. Monitors the structural health of the tunnel lining from the manufacturing phase. Based on an ultra robut 5-channel data logger, specially designed to be embedded within precast concrete segments. Connect vibrating wire technology instruments easily and safely: Strain gauges, Load cells, Any vibrating wire sensor. 19 Smart lining for tunnels TUNNEL MONITORING

20. Monitoring of the linings of a subway tunnel throughout its life cycle SUCCESS STORY Infrastructure OBJECTIVE Monitor the condition of the concrete segments, controlling the pressures and stresses that occur within them throughout their life cycle. Minimize downtime during installation (in the construction phase). INSTALLATION Vibrating wire dataloggers embedded in the concrete segments during their prefabrication Strain gauge sensors and load cells coupled to the armature. Gateways separated by up to 3 kilometers depending on the route of the tunnel.

21. Monitoring of the lining of a subway tunnel throughout its life cycle SUCCESS STORIES Infrastructure RESULTS The data shows the behavior of the segments during construction, storage and transportation. During installation, the load acquired by these elements is observed and how, from here, the status can be monitored, allowing structure maintenance based on information. BENEFITS Continuous monitoring of the state of the tunnel lining. The early installation during the manufacturing of the segment allows to monitor the entire life cycle from the factory to the service, including transport and construction phase, Early installation saves up to 25% of the effort involved in installing on the existing structure and yields more reliable results, since the sensors are in contact with the reinforcemen t. Maintenance/ In service period

22. Instruments inside tunnel structure (TBM section)

23. Alternative method based on measuring angles Measurand SAAV. 250 mm segment length Basset convergence system - Soil Instruments Basset convergence system - Durham Geo Slope Indicator

24. Alternative method based on measuring angles Strategies: High density of measuring points. E.g. Measurand SAAV. Mount the tiltmeters on beams equipped with ball joint. The tilt beams are chained and fit close to the tunnel walls. Tilt beam equipped with ball joints for being mounted in any orientation.

25. Conclusion In general, for the automatic convergence measurement in a NATM tunnel, the LaserTilt90 is a very good option. Main benefits: Minimize interference with tunneling activities. Ability to access data in near-real time and at the right frequency, enabling: Correlate changes with the excavation phases. Achieve rapid and informed decision-making to implement corrective measures. The LaserTilt90 may be easily relocated after the measured relative displacements are stabilized. The LaserTilt90 can be installed just after the initial support and relocated into the final lining. Measuring the relative distance and the angle it is possible to infer vertical settlement at the tunnel crown.