Profile Monitoring System
The Profile Monitoring System for Tunnel Concrete Segments is a series
of tilt meters, fixed to the tunnel wall on each of the precast concrete
segments erected in place as tunnel lining by a Tunnel Boring Machine
(TBM). The system is based on the assumption that each concrete
segment is a rigid body and that the complete ring deforms by rotation of
the individual segments one relative to the other, and the rotation points
are the contact surfaces between adjacent segments. This is considered
acceptable by tunnel designers and reasonably close to reality, although
spot checks using traditional convergence measurements or surveying
methods should be conducted to confirm its validity.
Applications
- Monitor the convergence of precast concrete segments in TBM-driven tunnels during construction
- Monitor tunnel deformation due to nearby construction activities
- Monitor long term deformation and performance of existing tunnels
Features
- Very low profile design, suitable for installation in the tight space available around TBMs
- No tunnel traffic interference
- High system accuracy
- Tilt meters can easily be redeployed periodically to follow tunnel face progression
- Built-in connectors for manual tape extensometer connection to verify operation, and aid in initial installation and commissioning
- Immune to the air density related problems inherent in optical systems
- On-board electronics to minimise electrical noise problems, and permit tilt sensor calibration independent of cable length effects. Cable length may be changed without affecting sensor calibration
- Near-real time software with full graphic and alarm capability
- Digital Bussed System: single, interconnected cable from one tiltmeter to the next, to simplify installation and reduce cost