Why is there a discrepancy in PLAXIS and SPOOKS results for stability analysis of retaining wall?

Question

I have done a PLAXIS 2d model and a Spooks model for analysis of retaining wall. I have included same input parameters for soil properties, loading, partial factors, water head etc...

What I found was the moment in the wall was comparable. However, the anchor loads in the PLAXIS 2d model is substantially larger than the spooks results.

Does anyone have a reasonable explanation for this variation?

Thanks.

Stefanos Papavasileiou · Answer

Dear Ruwanika, 
 Unfortunately, being from the support team I can only comment on the PLAXIS side. 
 When comparing results it is important to understand the different ways each application solves the analysis. PLAXIS is a finite element model while I noticed that this is not the case for the other model you created. 
 Among others, it is essential for a finite element model to have proper boundary conditions, accurate soil properties of the constitutive model in use, as well as good quality generated mesh. Then, the results can be reviewed and allow for comparison with other methods.