Desiccation shrinkage, residual effective stress measurement, unconfined compression, and consolidation tests were performed. The tests have been performed on two separate sets of overconsolidated samples subjected to mechanical unloading or desiccation, to examine the common conception that soil behavior based on mechanical unloading may be equivalent to that of desiccated samples. Reconstituted specimens of Ariake clay were used to investigate changes in engineering properties due to desiccation shrinkage. The purpose of this paper is to compare those results from samples subjected to mechanical unloading with a new series of tests on samples subjected to desiccated process of the same clay.
Overconsolidation history is one of the most important factors in geotechnical engineering for evaluating the shear strength and deformation characteristics of a soil. In general, natural grounds exhibit overconsolidation histories due to processes of mechanical unloading such as erosion, excavation, and changes in groundwater pressures. Due to changes in sea level, however, coastal areas include ground which has been exposed as dry land and has then again been submerged in the sea. Geological evidence suggests that in-situ overconsolidation ratio in waterfront areas may be greatly affected by shrinkage due to desiccation caused by sea level regression. Even though the soils were originally deposited under identical conditions, large differences in their engineering properties of these respective soils are possible. Attention, however, has mostly been paid to overconsolidated state due to processes of mechanical unloading such as unloading of external load, excavation, and changes in groundwater pressures. Laboratory tests have been performed on two separate sets of overconsolidated samples subjected to mechanical unloading or desiccation, to examine the common conception that soil behavior based on mechanical unloading may be equivalent to that of desiccated samples. Desiccation shrinkage, residual effective stress measurement, unconfined compression, and consolidation tests were performed.