distribution of earth stress

Question

Hello mr & mrs. I want to ask about how to find out the distribution of earth stress due to embankment load on Plaxis 2D? I am planning to install a PVD, where the regulations in my country recommend that the PVD must be installed at a depth of soil that has a stress distribution of less than 10% due to the embankment load. Thanks before...

Faseel Khan · Answer

In PLAXIS 2D output, the stresses menu gives options to view effective stresses, total stresses, principal stresses and water pressures as well. You will need the horizontal and vertical effective stresses which can be plotted as a shaded plot, contour lines or even as a graph and also tabulate the output results for post processing your own graphs in EXCEL for example. 
 
 Initially, in the initial phase, you will see a linear distribution of vertical stress due to the self weight of the soil. In the subsequent phases as the embankment is constructed in the staged construction mode, the stress distribution under the embankment will change due to the stress changes from the weight of the embankment. This will also affect the pore water pressures and so the effective stresses will change as well. 
 Users can plot the effective principal stresses from the stress menu. This plot shows crosses, some are rotated and some will be oriented vertically. The larger arm of the cross gives Sigma 1' and the shorter arm gives Sigma 3'. This also gives a good indication of the stress state in the soil. 
 Output plots in soils is demonstrated in the following video: https://www.youtube.com/watch?v=zuK8UGcuduI 
 Plotting of graphs in output is demonstrated in the following video: https://www.youtube.com/watch?v=xasfdG-2G_U