Effect of Vacuum Pressure Distribution on Settlement Analysis Results for an Improved Thick Soft Clay Deposit at Sai Gon-Hiep Phuoc Terminal Port, South of Vietnam

Abstract

In the recent years ground improvement with preloading, PVD and vacuum pressure has become commonly used for many projects in Southern Vietnam, including that of Sai Gon-Hiep Phuoc (SGHP) terminal port. At this project site a very soft to soft clay layer was improved by a combination of three techniques as mentioned above. As the clay deposit is very thick, extending from the surface to the depth of 35m, the effect of vacuum pressure along the PVD and the immediately surrounding soil is of particular interest in term of its influence on the settlement analysis among other parameters, commonly considered in settlement analysis, such as soil properties, smear zone, PVD spacing etc. In this study, the effect of ratio between vacuum pressure at the bottom and the top of the drain (kp) on the settlement analysis results, was investigated using a Fortran code. It was found that kp varied from 0.85 to1.0 and its value could affect the matching of the calculated settlement curve with monitoring data if not properly chosen. In addition, the smear effect with RS equal to 3.0 and a PVD spacing of 1.0 m were found as optimal values for settlement analysis at the SGHP site.