Efficiency of Vacuum Preloading on Consolidation Behaviour of Cochin Marine Clay

Greater Cochin area is rich in deposits of marine clay which has been identified as a problematic soil which undergoes long term settlement due to consolidation. An alternative method of consolidation by the application of vacuum pressure can be used to reduce the risks of staged construction of embankments and the consumption of large amount of filling materials. Consolidation tests were carried out on samples prepared in the consolidation cell under three different magnitudes of vacuum pressure, with and without the use of PVDs. The results obtained were then compared with the similar magnitudes of surcharge preloading. Tests were also conducted in larger specimens of soil samples, the obtained results of which were comparable with that of the oedometer samples. The coefficient of consolidation was found to increase by 65% and the time for 90% of consolidation has reduced by 70%, with the use of vacuum method of consolidation.