UNDERGROUND OIL STORAGE FACILITIES IN JAPAN

In Japan, three underground crude-oil storage facilities with a total capacity of 5 million kl are under construction as a chain of the nati onal oil storage project. Because the NATM method was used in this pro ject, we applied a systematic work control system, consisting of in si tu measurements and engineering geological observations, including an original rock-mass classification system. The classification system us ed can be slightly modified depending upon site-specific geological co nditions and the purposes of the facilities such as, i.e., an artifici al water sealing system.