1994 Volume 4 Pages 365-370
Collapse of the cutting face and displacement by the shortage of the bearing capacity are main problems in the nucousolidated pumice ground tunnel drive.
Pre-lining method and other measures have been applied in order to overcome these prpblems. The results are as follows.
1. The cutting face was stable due to the umbrella of the pre-lining, which is to cast the mortar liner in the shape of arched shell in front of the face prior to to the excavation.
2. The displacement of the tunnelwas effective restricted by the injection type foot-piles, reinforcement concrete at the leg of the heading etc.