how to solve warning code 5 in plaxis "some stress points violated either the fairlure criterion or tension cut-off criterion" ?

Hi Randy,

As per Appendix I of PLAXIS 2D – Reference manual, Error Code 5 means that one or more Tension of Mohr-Coulomb points was found in the model.
The reason for getting this error might be related to the K0 procedure and the value provided for K0. Using very low or very high K0-values in the K0 procedure may lead to stresses that violate the Mohr-Coulomb failure condition. In this case, PLAXIS 2D automatically reduces the lateral stresses such that the failure condition is obeyed. Hence, these stress points are in a plastic state and indicated as plastic points. However, although the corrected stress state obeys the failure condition, it may result in a stress field which is not in equilibrium.

It is generally preferable to generate an initial stress field that does not contain Mohr-Coulomb plastic points. So, please inspect the Output for the Initial phase (K0 procedure) and check the K0 values for the materials where the plastic points occur.

and this is the output of plastic points when I checked, before I changed the k0 value of the procedure

Hi Randy,

The plastic points shown in the second image show precisely what I mentioned in my previous reply. The material of the top layer plasticizes under its weight in the Initial Phase between elevations (-7m) and (-26m). Therefore, you should check the principal stresses or, even better, select the "Hint window" on the left toolbar in Output while hovering over these plastic points to better understand your soil's stress state.
Regarding your second question, Error 104 hints that the prescribed time interval in a consolidation analysis is not reached. This is probably due to soil failure, so you should inspect the input data and the calculation results in Output to evaluate why it fails.

I am afraid that in the absence of any meaningful information on your project's material parameters, flow conditions, etc., I cannot assist you further. Therefore, if you don't manage to find a solution, you should submit a Service Request via the following link:
apps.bentley.com/.../ProductSupport

Hi Randy,

The plastic points shown in the second image show precisely what I mentioned in my previous reply. The material of the top layer plasticizes under its weight in the Initial Phase between elevations (-7m) and (-26m). Therefore, you should check the principal stresses or, even better, select the "Hint window" on the left toolbar in Output while hovering over these plastic points to better understand your soil's stress state.
Regarding your second question, Error 104 hints that the prescribed time interval in a consolidation analysis is not reached. This is probably due to soil failure, so you should inspect the input data and the calculation results in Output to evaluate why it fails.

I am afraid that in the absence of any meaningful information on your project's material parameters, flow conditions, etc., I cannot assist you further. Therefore, if you don't manage to find a solution, you should submit a Service Request via the following link:
apps.bentley.com/.../ProductSupport

thank you very much for your attention and answer. may you always be given health by god mr Vasileios Basas

You are welcome. May you be also blessed with good health