Ground Surface
A Ground Surface can either be drawn within UnWedge, or it can be imported as a DXF file.
To add a Ground Surface, select Boundaries > Add Ground Surface 
from one of the 2D views (e.g., Opening Section, Perimeter Support Designer).
Enter the coordinates of the Ground Surface as described in the Entering Coordinates topic.
Ground Surface Definition
The Ground Surface in UnWedge acts as an upper boundary for Perimeter Wedges. Any Perimeter Wedges extending beyond the Ground Surface will be truncated.
A ground surface can also be used as a piezometric line as explained in the Water Pressures topic. It is also used as the Ground Surface Elevation (instead of user input) in a Gravity Field Stress Analysis.
Bolts are not allowed to penetrate through a Ground Surface.