Volume 3, Issue 7 (July 2006)
Effect of Specimen Size on Consolidation Parameters of Marine Clay Deposits
The effect of specimen size on consolidation parameters of undisturbed marine clay deposits and their remolded samples are examined through the standard incremental loading oedometer test I.A.W. JIS A 1217. There are two sizes of specimens, a d60 specimen (60 mm d and 20 mmh) and a d30 specimen (30 mmd and 10 mmh). The relationships between void ratio and consolidation load were unrelated to specimen size in the loading and unloading process. The coefficients of consolidation (cv) obtained from the d30 specimen were smaller than those of the d60 specimen in the over-consolidated stage. This was caused by larger t90 values (the required time for 90% consolidation) of the d30 specimen than those of the d60 specimen. The t90 ratio was about 1.3 in this stage. In the normally consolidated stage, the cv, coefficient of volume compressibility (mv), and permeability (k) were unrelated to specimen size. The consolidation parameters obtained from the d30 specimen were almost the same as those of the d60 specimen in the normally consolidated stage. The d30 specimen, retrieved from the 45 mm, small tube sampler or a 75-mm sampler, is more effective for sample testing purposes.