ABSTRACT
The essential factors of frost damage of tunnel in frozen earth are as follows: the temperature situation, the hydrological condition, the condition of surrounding rock and the measure of tunneling. Through researches to lots of tunnels’ frost damage phenomena and its mechanical principle, we discover that the mechanical character of frozen soil differs greatly from other types of soil. The main reasons for frost damage taking place include: the volume expansion and the change of physical mechanical character of soil when the unfrozen soil transforms to frozen one, and frost force to tunnel lining. Therefore, the key point of study to tunnel in frozen earth is the mutual effect of unfrozen surrounding-rock, frozen-area and tunnel lining, and we should make frost force of tunnel in frozen earth clear.
