Set/Clear Ground Surface

This option allows you to set a ground surface with selected plane. When you define ground surface, EX3 will allow users to apply gravity load from the defined ground surface.

When you assign a surface to ground surface, the message will pop up stating the following:

"The field stress definition has been changed to reflect the addition of the ground surface".

This message is to encourage you to assign gravity as field stress where the ground surface becomes the reference point. When you select OK, you will notice the field stress type has changed to 'gravity' with 'use actual ground surface' option checked.

The reason for this pop-up message is that EX3 assumes the excavation is surrounded by infinite domain if you have not defined the ground surface for gravity load. The use of ground surface will allow zero stress condition on the surface and the field stress increase as the excavation is dug deeper away from the surface.

Clear Ground Surface

This option allows you to clear any geometry that is assigned as ground surface to be removed.