Consolidation Analysis with Application of Constant Rate of Strain Consolidation Tests for Vietnam Clays

Constant rate of strain (CRS) consolidation testing has specific advantages over the standard incremental loading (IL) consolidation testing. The first advantage is shortening testing period of 1–2 days compared to 7–10 days for the standard; the second one is that testing data are recorded automatically and continuously for the ease of determination of consolidation yield stress. Moreover, pre-consolidation pressure from CRS is larger than that resulted from IL, so many researchers have not recognized the application of CRS into the routine design of consolidation problems. Therefore, there has been little effort and application of CRS in the consolidation analysis into the soft ground improvement especially in Vietnam. There has been no standard for CRS applicable in the soft ground improvement design in Vietnam. The paper is focused on characterization of Vietnam soft clay deposit with application of the results of constant rate of strain consolidation tests in order to achieve the input parameters for consolidation analyses. Total 4 PVD and surcharge construction sites with the undisturbed samples taken by stationary hydraulic piston sampler are investigated in this study. The characterized input data are utilized in consolidation analyses by finite difference method (FDM) in order to determine the behavior of Vietnam soft clay deposit. A comparison of the monitored data to the calculated data from a new finite difference code which has been developed by the author is presented.