In Japan, a lot of underground structures have been constructed in spite of complex and poor geological conditions and are now in use. On the other hand, an aseismic design to prevent the severe accident of structures is very important in Japan. Though, an aseismic design of structures constructed in rock has not been well discussed up to now. This is because we have had a tacit understanding that a seismic vibration is small enough in the deep underground and underground structures do not respond like structures which have been constructed on the ground surface. However, in the recent earthquakes which had caused a lot of structural damage, some cases where tunnel structures had been damaged had been also reported.
So, the aseismic design for the structures constructed in rock mass should be discussed as an important and urgent problem, especially for the new structures which are going to utilise various properties of rock mass. They are high-level radio-active waste disposal facility, and underground storage facility for oil and gas. If these underground facilities are damaged and lose their functions by great earthquake, a social influence is too serious.
In this paper, the present situation of static and aseismic design for underground structures ranging from cut-and-cover tunnel in a shallow ground to mountain tunnel in the deep rock mass is reviewed. And problems that should be discussed to establish a proper method of aseismic design are presented.
