This type of analysis can be done a few different ways in RS2. Three files have been attached to this article, illustrating three different ways that this problem can be modeled. All three models give similar results.
The first model uses a liner element with a piezometric line for pore pressure.
Sheetpile wall 1: liner element with piezo line
The second model uses a structural interface with a piezometric line.
Sheetpile wall 2: structural interface with piezo line
The third model uses a structural interface with a groundwater analysis for pore pressures.
Sheetpile wall 3: structural interface with groundwater analysis
The difference between a beam element and a structural interface is that the structural interface also models slip between the pile and the soil. The beam elements are directly attached to the soil. Also note that ponded water tractions are used to model the ponded water; this is discussed in Tutorial 7. In case the ponded water load is created in the wrong direction, the load direction can be flipped. Another important note is to make sure that automatic liner removal is turned off.
For more information on finite element groundwater analysis, see Tutorial 7 and Tutorial 13.