Superposition law and coupling in verified model
Based on the verified model two separate cases were considered as:
(a) Only surcharge preloading without PVDs and (b) vacuum and PVDs.
(a) surcharge and PVDs and (b) vacuum and PVDs
Since the percentage of PVDs contribution in consolidation is not clear both cases as in present and in absence of PVDs were considered. Three main parameters as settlement (centerline), lateral displacement (toe of the embankment), and excess pore pressure (3 meters beneath centerline) were evaluated. Figure 3 shows the results of FEM modeling where verified FEM models are shown vs. only surcharge, vacuum and PVDs, and the algebraic summation of only surcharge and vacuum and PVDs. It should be noted that in summation of all cases for excess pore pressure the absolute value of excess pore pressure is considered. Although it is not wise at all, to sum up the excess pore pressure resulting from surcharge with resultant excess pore pressure of vacuum water head, unfortunately, there were no other ways to show their effect. For a demonstration of the effect of each case in the SUM value, the related individual curves are shown beside the SUM curve.