EVALUATION OF FIELD PERFORMANCE OF PREFABRICATED VERTICAL DRAINS (PVD) FOR SOIL GROUND IMPROVEMENT IN THE SOUTHERN VIETNAM

Abstract

A 40,000-km2 soft ground area in the southern Vietnam is big obstruction for infrastructure development in Vietnam. PVD is the most popular technique applied to improve soft ground in the southern Vietnam. However, field performance of PVD based on field monitoring is quite discrepant from prediction. This study aims at better understanding of PVD field performance via case studies. The two complete projects using PVD for soft ground improvement were utilized for back analysis. Field monitored settlements agree well with predicted settlements when the field settlement has experienced a settlement of 0.3 m or less. The predicted settlement exceeds the field monitored settlement about 50% when the field settlement reaches 0.5 m or larger. The result indicates that degree of filed consolidation was less than 90%, and large field settlement keeps occurring during the service stage of highway embankments and may cause field settlement over the allowable settlement according to the Vietnam Code for soft ground improvement.