Three-Dimensional Finite Element Analysis of a Trial Embankment

Commonly finite element analyses of embankments and excavations are conducted as two-dimensional representations of the true three-dimensional problem, but very little work was done in determining the relative applicability of these solutions until recently, when three-dimensional programs and high-speed computers became available. A trial embankment constructed in Vaasa (Finland) is analyzed in this paper. The main purpose of the construction was the testing and development of the design methods for the planning of road embankments. Settlements at the base level of the embankment were measured with settlement plates, and deeper in the ground with magnetic extensometer. The pore pressures were measured using open and closed piezometer tips installed at different depths. For the task of analysis carried out in this paper, a finite element computer program named (3-DFEP) was written. The program can solve three-dimensional coupled problems. Both the soil solids and the pore water are modeled by 8-noded brick elements. It was found that the results of three-dimensional analysis are more stable than do plane-strain ones. The settlement became approximately constant after about (600) days. The settlement predicted at that time was approximately (400) mm that is in good agreement with the recorded field data while plane-strain results showed continuous increase in settlement after that time.