STABILITY ANALYSIS OF TUNNEL HEADING BY RIGID-PLASTIC FINITE ELEMENT METHOD

Abstract

The stability analysis of the tunnel heading is studied by means of the rigid-plastic finite element method which is exclusively applicable to the behavior of the critical state of the surrounding ground of the tunnel. It is confirmed that the apparent cohesion of the soft sandy ground, even if it is of a small value, plays an important role to sustain the stability of the tunnel face as was pointed out by Mashimo. The effects of the existence of the un-supported region and the pre-lining on the stability are also considered in relation to the required minimum value of the apparent cohesion.