Analysis > Options > Host Stress Datum is Ground Surface

Specifies that the host material #1 stress datum will be treated as ground surface - during Map3D BEM analysis.

When not checked, all excavation surfaces are assigned zero stresses.

When checked, all element surfaces with z-coordinates above the host material #1 stress datum (it is assumed that z is positive upwards), will be assigned stresses equal to the specified pre-mining Stress State values. This minimizes the influence of these elements and thus improves accuracy. Note that this is only effective when the ground surface is planar.

Notes:

This function must be checked before conducting the Map3D BEM analysis

Analysis > BEM Analysis

This option does not require any additional calculations and hence will not increase analysis time.