Experimental and Numerical Investigations to Evaluate Two-Dimensional Modeling of Vertical Drain–Assisted Preloading

Abstract

In this study, the efficiency of proposed formulations for plane-strain modeling of vertical drain–assisted consolidation was evaluated. For this aim, the vertical drain–assisted preloading process was experimentally simulated using a fully instrumented large-scale Rowe cell. Nine pore-water-pressure transducers were installed in various locations to measure the changes in pore-water pressure during the test. Two pressure/volume controllers were connected to an infinite-volume controller to provide continuous water flow. Soft clays with predefined properties were used to form the intact and smear zones. A numerical code was developed by using the finite-difference program FLAC 2D to simulate the consolidation test. A numerical study was conducted to evaluate the efficiency of the proposed solutions for converting the axisymmetric state to a plane-strain condition and was subsequently compared with corresponding numerical analysis. From the results, it is observed that some of the proposed methods resulted in more accurate predictions of settlement and changes of pore-water pressure in the early stages of the consolidation process, whereas other proposed methods performed more accurately in the later stages of consolidation. Thus, three-dimensional modeling with actual soil-permeability properties to simulate the time-dependent behavior of soft soil improved with vertical drains is recommended.