SEISMIC/POST-SEISMIC RESPONSE OF A NATURAL SOIL IN DELAYED SETTLEMENT

摘要

This paper is a natural extension of the former paper (Asaoka and Noda, 2007), published by the same authors in the international workshop on Constitutive Modelling held in Hong Kong. The behavior of a naturally deposited soil in a delayed consolidation phase during/after and earthquake is presented as a soil-water coupled calculation example. Emphasis is laid throughout on the importance of an analytic technique that copes consistently with all soils, clay or sand, in all states, consolidated or liquefied/compacted, and is sufficiently all-round to cover both static and dynamic problems. The soil in the example consists of an 8m top-layer of sand and a 13m under-layer of alluvial clay, and has undergone more than 20 years of continuous consolidation settlement since being loaded with a highway embankment. Settlement loss exceeds 3m, and no end to the process is yet in sight. After showing that delayed compression of this kind is due to a progressive breakdown in the clay skeleton structure, this paper makes clear what will happen at this site if the top-layer of sand is liquefied by being struck by an earthquake and sustained consolidation/shear deformation then continues in the clay under-layer for several tens of years.