Profile Monitoring System for Tunnel Concrete Segments

This Profile Monitoring System using tiltmeters is a simplified
version of the Tunnel Profile Monitoring System (see separate data sheet) and its main advantage is that it can be deployed in the tight space available around the TBM (Tunnel Boring Machine).

A series of tilt meters are fixed to the tunnel wall on each of the precast concrete segments erected in place as tunnel lining by a 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 assumption is very often considered as 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 for individual tunneling circumstances.