Settlement Calculation and Back-Analysis of Soil Properties for a Test Embankment on a Soft Clay Ground Improved by PVD and Vacuum-Assisted Preloading at a Site in Vung Tau, Viet Nam

Abstract

Application of vacuum assisted preloading is helpful when a considerable load is required to meet the desired rate of settlement and an increase in the undrained shear strength in a relative short time. To facilitate the vacuum propagation, vertical drains are usually employed in conjunction. A pilot test was carried out at a land reclamation project to study the effect of ground improved by vacuum combined with PVD and surcharge preloading on the rate of consolidation of a soft clay at the site of Saigon International Terminals Vietnam (SITV) in Ba Ria-Vung Tau Province, Viet Nam. Theorectical analysis were conducted to interpret the field measurements of pore pressure and settlement, and consolidation parameters were back — calculated. The degree of consolidation estimated from the settlement is higher than that obtained from the pore-pressure dissipation measurement. The coefficient of consolidation back — calculated from the settlement is slightly larger than that obtained from the pore-pressure measurement. Furthermore, undrained shear strength was back– calculated and compared with those obtained from soil investigation after treatment.