ABSTRACT
ABSTRACT: This study outlines the geotechnical performance, such as ground subsidence, that occurred on the premises of the Kashiwazaki-Kariwa Nuclear Power Station as a result of the Niigataken Chuetsu-oki earthquake on July 16, 2007 (magnitude of 6.8 on the JMA scale). Whereas the plant buildings, buried ducts, and other major structures are supported by Tertiary beds, the surrounding areas are backfilled with alluvial and Pleistocene sands of 10 to 25 m in thickness. Subsidence of a few tens of cm to more than 1 m (1.6 m maximum near the buildings) occurred widely in the backfill areas where the soil was dewatered and unsaturated, causing damage to nearby equipments resting directly on the soil. The large subsidence of the backfill soil corresponding to compressive strain up to 6% near the buildings may be explained by cyclic shearing of unsaturated backfill soils reflecting the soil-structure interaction.
