CAD > Properties > Material Properties > Stress State > Cartesian

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The pre-mining stress state is specified as a linear variation with depth in either Cartesian or principal components.

 

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The variation of each of the Cartesian components is described as a linear variation with depth as (for example for the σxx component)

 

σxx + Δσxx (z - Datum)

 

To determine appropriate values for each of these components the user must first select a depth

 

(z = Datum)

 

where the stresses have known values. These later values are the

 

σxx σyy σzz τxy τyz τxz

 

constant values.

 

The variation of each component with depth can then be specified as

 

Δσxx Δσyy Δσzz Δτxy Δτyz Δτxz

 

variation values. If you have set up your coordinate system with z positive up, then the variations should be specified as negative quantities so that the stresses increase with depth.

 

For example if you know that the σxx component has a value of

 

30 MPa at z = -1000m

 

and varies as (z is positive up)

 

0.027 MPa/m

 

you would specify

 

Datum = -1000

σxx = 30

Δσxx = -0.027