There are two ways to do this in RS2:
- with a low permeability material
- with a structural interface with an impermeable joint.
For the first method, you must use a low permeability material next to the sheet pile wall. In Tutorial 13 the sheet pile permeability is set to 1e-20, which is a very low value. Remember that we cannot choose 0, since this will lead to numerical instability.
Cofferdam model with impermeable diaphragm wall
For the second method, you need to ensure that the Permeable option is not selected in the joint used in the structural interface. This will ensure a "no-flow" groundwater boundary condition across the joint. Tutorial 39 illustrates this method.