Rock Mass Classification Based on Convergence Measurement in Tunneling

Abstract

Convergence monitoring can be easily carried out during construction and provides serial information on final deformation of tunnel wall, support load, development of the inelastic zone, etc. The authors estimated the width of the inelastic zone from the results of convergence measurements which had been carried out in sedimentary rocks, and clarified the relationship between competence factor and deformation rate. It was concluded that the allowable limit of deformation in tunneling (ΔD/D) must not be beyond 2%.