ESTIMATION OF FLOOR HEAVE MECHANISM OF ROCK TUNNELS FOCUSED ON THE CHANGE IN WATER CONTENT

Some mountain tunnels in service suffer from floor heave, and some of them require countermeasures. Case analysis and literature survey were conducted in order to clarify the mechanism of floor heave. From these, it was found that the information at the time of construction couldn’t explain the floor heave after completion enough though floor heave and water was closely related to the floor heave. Furthermore, rock tests and a model test were carried out. These results reveal even if there is little spring water at the time of construction, water will be supplied in some way after completion, and that may lead ground deterioration, and sudden change in water content may lead sudden floor heave. Based on these results, the authors have shown some scenarios of floor heave mechanism of the mountain tunnels, focusing on the amount of spring water at the time of construction and the water supply after completion. 48