Abstract
The present study addresses the ageing of liquefaction resistance of sand in which the resistance increases with the age of soil. This topic is getting more important in recent times because the more reasonable assessment of the resistance is required for more reliable hazard mapping. This situation is in contrast with the conventional idea in design codes that allows a conservative assessment of the resistance. To achieve this research aim, liquefaction case histories were collected from Tokyo and Osaka-Kobe areas where subsoils of known age either liquefied or not liquefied. Consequently, the ageing effect is able to be assessed quantitatively and the liquefaction resistance of soils over 400-year age can be increased 40% above the conventional assessment in design codes.
