safety analysis procee

Question

hi,dears! 
 I am building a slope model. After generating the strata, I did a safety analysis and got a Factor of safety of 3.54. I am wondering if this value is too large? If I'm right, ask what factors affect Factor of safety? Soil parameters? 
 In addition, the total displacement cloud map obtained is of a large order of magnitude, is this cloud map need not pay too much attention to it? 
 thx.

Stefanos Papavasileiou · Answer

Dear Xiong, 
 The value of the factor of safety may be large as the curve point is outside the failure zone. Make sure to select a couple of curve points within the red-orange zone to retrieve the correct safety factor. 
 With regards to the deformations, please check this article: https://communities.bentley.com/products/geotech-analysis/w/wiki/45939/safety-analysis-and-displacements 
 As for On-Demand items, you can check one of our Coffee Corner on Using PLAXIS to Determine Factors of Safety: https://event.on24.com/wcc/r/2165515/6BA8A61A920F589C3E5C23DA3B23FDD6?partnerref=GeoAnalysisBC

Stefanos Papavasileiou · Answer

Hello Xiong, 
 I have to correct myself here, as in my answer I confused the safety factor and the result of the deformations. 
 In PLAXIS the &Sigma;&Mu;sf (safety factor) is a total multiplier which has a global value and that is relevant (and the same) for your whole model irrespective of where you check or what curve point you have selected. 
 So, if you are interested only in checking the value of &Sigma;&Mu;sf (safety factor) it does not matter where you check it as it will always be one value per step. For a quick look, you can check that already in Input for the last step: 
 
 But also in Output in more detail: 
 
 Now, more on what I confused you with: selecting a curve point. 
 By selecting a curve point inside the failure area, you can easily plot deformations vs. safety factor. While the safety factor will be the same irrespective of the location your curve point is at, the value of the deformations will change whether you are inside a failure zone or far away from it. 
 We recommend selecting a curve point inside a failure zone so that you can see relevant deformations to the failure, as outside the failure zone the deformations would be quite small. 
 I hope it is clear now. 
 With regards to the deformations, please check this article: https://communities.bentley.com/products/geotech-analysis/w/wiki/45939/safety-analysis-and-displacements 
 As for On-Demand items, you can check one of our Coffee Corner on Using PLAXIS to Determine Factors of Safety: https://event.on24.com/wcc/r/2165515/6BA8A61A920F589C3E5C23DA3B23FDD6?partnerref=GeoAnalysisBC