Deformation behaviour of clay under repeated one-dimensional unloading-reloading.

The deformation of clayey soil under repeated cycles of unloading and reloading has been investigated in oedometer tests using both undisturbed and reconstituted Ariake clay samples. The test results indicate that even for repeated unloading-reloading in the overconsolidated stress range, the deformation of the soil sample is not purely elastic and there is an accumulation of permanent deformation. Based on the test results, a model has been proposed for predicting unloading-reloading-induced deformation. The proposed model has been used to simulate the behaviour of a clayey soil deposit in the Saga Plain, Japan, in response to groundwater fluctuation. Good agreement between the simulation and the field measurements indicates that the proposed model can be used to predict land subsidence induced by groundwater fluctuations. [ABSTRACT FROM AUTHOR]