RCMS – Ring Convergence Measurement System
RCMS is a hardware and software components-based system solution to measure ring convergences and is specially optimised for tunnelling projects with segmental lining. Ring convergences are deformations resulting from environmental pressures (rock pressure, annular gap injection) after the installation of a ring.
- Quality always in view
Deformations of already built rings are detected early. This ensures the quality of the tunnel structure.
- Reduced personnel expenses, complete overview
Automatic data acquisition as well as simplified monitoring, logging and archiving provide numerous simplifications and increased transparency.
- Quick installation and deinstallation
Wireless communication of the system components, battery operation and glueing of the reusable, non-segment-damaging sensors all minimise time expenditure.
- Early control
Unlike conventional manual methods, the measurement starts immediately after ring completion, in order to detect convergences directly after leaving the tailskin.
- Measurements with added value
In contrast to conventional convergence measurements, RCMS additionally records all ring segments in the gantry area. This ensures a precise and thorough measurement of the entire ring.
- The perfect grout mix
Based on the measured data, the grout composition can be optimised – reducing costs while ensuring the quality of the tunnel structure.
- Specially optimised for shield tunnelling with segmental lining
- Supply of all necessary hardware and software from one source
- Flexible selection of the reference route to be monitored
- Significant accuracy of ±1 mm
- Recording and evaluation of small time intervals (minimal 5 seconds)
- Recording both of convergences and relative deformations of a ring in the form of movement vectors
- Fast, wireless installation using wireless technology and reversible adhesion of the sensors
- Wireless data transmission
- Space-saving sensors with integrated current supply
- Software with comprehensive evaluation and display options
- Permanent display and monitoring of measured values
- Automatic recording and archiving of the data
- PDF reports can be automatically generated for documentation
- Interfaces for data evaluation and archiving in external systems
London Power Tunnel | Hurst – Crayford: total 2517m
- Situation: 1 drive – 1 curve
On a 300m radius curved alignment with 277m the total station requires about every 6th Ring (each 7,2m advance) to relocate. On the straight sections of the alignment it is about every 20th Ring.
• By calculation this equals the saving of time to fix 38 laser station positions that have to be drilled and mounted onto the ring segments.
• Bracket drilling and placing surveyor and assistant 0.5 man-hours each.
• Total saving in man-hours 0.5*2*38 = 38 hours for a 277m curve
- Situation: all drives
- Summary: Assuming that every 6th ring in a curve you need to relocate the TCA)
► Savings for the whole project
1637 man-hours by using the TUnIS.moving station
- Test position with self-levelling tribrach in orange
- Right beside (helmet) will be the final position of the tachymeter after swap from the currently running system TUnIS Navigation TBMLaser to TUnIS.moving station
- We are using prisms clued on the segment → no need of drilling and no risk of damages
- Yellow standard survey prism
- Next to it the blue TUnIS.moving station prism
- Large laser window for a comfortable use of TUnIS.moving station
- Test position TUnIS.moving station on gantry 1
- Short distance to shield
- Laser point on electronical laser target
Thomas Unterfeld, Survey Coordinator
Implenia Construction GmbH Tiefbau
Project: Albvorlandtunnel, Lot 2
Why did you decide to use RCMS for this project?
“The service description of our contract demands the monitoring by means of a measuring system for the continuous monitoring of ring convergence. As there were no comparable alternatives in terms of similar performance spectrum or promise from other manufacturers and given that we were familiar with the RCMS predecessor from a previous project, we decided to go with RCMS in its new further-developed and optimised version. The main arguments for the VMT RCMS system that convinced us to move forward with this product was our experience of the company’s reliable employees and the availability of full system support when required and the stability of the RCMS. So far the system has fully met our expectations.”
Did RCMS provide additional capabilities over the course of the project?
“By using the two new systems, which we had already used in their test phase and which could still be optimised to our project requirements, we were able to achieve significant improvements in respect of our monitoring process. For example assembly times were shortened substantially and the resources needed were also reduced. Instead of 2 or 3 persons working for 2 hours or more, the assembly requirement was reduced to 2 persons working for a maximum of 15 minutes.”
How would you summarise your experience with RCMS system and VMT?
“The direct selection of the RCMS meant that we were able to facilitate the necessary requirements of our particular system quickly and efficiently with our needs being achieved by VMT under strict time limitations. The installation process was excellent and the ongoing support cannot be faulted. The system has offered us better and more stable functionality as well as hardware savings. There is also the advantage of having a direct contact person. Ultimately we have to date been extremely pleased with the modifications to the basic system provided by VMT to ensure our system fitted our purpose exactly. Would we use RCMS again? Yes, most definitely, particularly as it would partner us again with the VMT team.”