PERFORMANCE OF CONSOLIDATION TECHNIQUES FOR IMPROVEMENT OF NEWLY DEPOSITED DREDGED MUD BY SCALE MODEL TEST

Abstract

As an attempt to promote utilization of newly deposited dredged mud as fill material for
reclamation sites, this study observes performance consolidation methods for dewatering of liquid mud which
is taken from a lake in Hanoi city. Various tests were conducted to observe basic engineering properties of the
mud. Subsequently, sets of scale model tests have been established to simulate both self-weight consolidation
and prescribed vacuum consolidation. In the first test, the liquid mud is placed into a steel box and deposited
by self-weight of fine particles. In the later test, the liquid mud is preloaded using the vacuum pressure. Test
results reveal that the self-weight consolidation method shows very low performance, whereas the vacuum
consolidation method give much higher performance. In addition, to address the clogging phenomena, vertical
drains among Prefabricated Vertical Drain (PVD), Sand Drain (SD) and Filter Pipe (FP) during vacuum
consolidation are investigated based on the monitoring data of settlement, water content, undrained shear
strength and influencing zone surrounding the vertical drains. As the goal, the SD is suggested for vertical drain
during vacuum consolidation when volumetric strain in case of SD, FP and PVD are 12%, 9.1% and 6.2%,
respectively.