Abstract
Akita National Oil Reserve Base which has a total storage capacity of 4.5 million kilolitres is now under construction in Oga city in Akita prefecture. In this report the civil engineering works of four in-ground oil tanks which have a capacity of 305000 kilolitres each are introduced.
The tanks are now near completion using the usual lining method with soldier pile and rock anchor retaining walls in a mudstone stratum. The excavation work, which has a diameter of 96 meters and a depth of 39 meters, is one of the largest vertical excavation works in Japan. Focuses are mainly in the introduction of the design concept, the analysis of monitering during the excavation, and the evaluation of the design concept.
