When viewing nodal interface results in a tabular format within Output, users may notice that the results are separated into two columns: "Node" and "Wall Node" results. Additionally, certain results feature an asterisk (*) adjacent to the node number within either of these columns.
Figure 1. Table results showing the "Node" and "Wall node" columns
Interface elements are composed of pairs of nodes in which the nodes in a pair have the same coordinates.
The asterisk serves as an indicator for the corresponding elements in the results. For instance, when the asterisk is placed in the "Node" column, PLAXIS displays the results related to the soil element. Conversely, when the asterisk appears in the "Wall node" column, PLAXIS exhibits the results pertaining to the structural element (i.e., plate, geogrid, etc.). This distinction facilitates the assessment of relative displacements between the soil and structural elements.
Figure 2. Differentiation between soil and plate results (example)
One can readily visualise the nodes by examining the Connectivity Plot (Ctrl+0) in the Output section and employing the Selection Explorer to locate the nodal numbers.
Figure 3. Visualisation of the nodes in PLAXIS Output
When an interface is positioned between two adjacent soil clusters, the term "Node" denotes the node associated with the interface, while the term "Wall node" refers to the node pertaining to the soil. This principle holds true even in cases involving a double interface comprising both positive and negative interfaces. The only distinction is that instead of one pair of split nodes, there will be two: one set consists of the "Node" representing the interface and the "Wall node" representing the soil for the positive interface, and another set for the negative interface.
Figure 4: Interface elements between soil clusters
Modelling soil-structure interaction: interfaces [Tips and Tricks]
Interface Elements in PLAXIS and How to Use Them [Answer Hours]