Abstract
Convergence monitoring is a simple measurement. It can be easily carried out during construction, and provides serial information on the deformation of tunnel wall. When the ground behaves as an elastic body with no time dependency, the curve of convergence reaches a constant level within the range of a double distance of the tunnel diameter in the driving direction. On the other hand, when the ground is subject to the inelastic behaviour, deformation converges in the distance of 3 to 10 times longer than the tunnel diameter.
The authors analyzed in detail the results of convergence measurements obtained from 60 tunnelling sites, and clarified the relationship between deformation and support load.
