1994 Volume 4 Pages 323-328
In order to excavate a tunnel in safety, it is important to keep the tunnel face stable. But now there are no criteria to evaluate the stability of the tunnel face easily, so some accidents of the tunnel face collapse have happened owing to the lack of the countermeasures for the tunnel face collapse.
In this paper, model tests on unsaturated sand were carried to investigate the ground condition when the tunnel face collapse happens and the results of the model tests were analyzed by the three-dimensional stability analysis. From the model tests and the analysis, the author could obtain a criterion to evaluate the face stability.