Rock Engineering in Underground Space Utilization in Japan- Experience of Underground Energy Storage Projects

Japan has utilized large underground rock caverns for various energy storage since early 1970s.Major outcome of rock mechanics and hydrogeology are reviewed based on the 30 years experience of design and construction of pumped storage electricity storage and underground crude oil and gas storage projects. World largest underground LPG storage caverns under construction are introduced. In this paper, the methodology of design and geoinformatics based observational design and construction technologies being adopted in the projects are described with highlight to rock mechanics and engineering. Future scope and some new technologies are briefly introduced.