Dear
I am modelling the rainfall in a specific area in the Plaxis 3D FEM and defined the polygon to determine the rainfall in that area. The specification I used in different phases are as follow:
Initial phase:
Calculation type: Flow only
Pore pressure calculation type: steady state groundwater flow
…
2nd phase:
Pore pressure calculation type: Transient groundwater flow
Time interval: 15 days
Max number of steps stored: 250
In this regard, in the 1st model I just modeled a simple rectangular surface and then after that I defined a polygon (“create surface ground water flow boundary condition” option) on the surface and defined infiltration for that area, and the results clearly showed the change of water pore pressure in the model for the specific area as follow:
In contrast, in the 2nd model I imported point cloud data from real survey and when again defined a polygon, with for example 8 vertices (nodes), in the calculation phase, it divided my polygon in 3 different polygon and it seems some part of the polygon goes under the ground, which I can not see some part of this polygon in the model. I used the option “project points to plane” to best fit the polygon on the surface.
In this regard, when I run the model it does not show any changes in the pore water pressure in the polygon area. It seems it does not understand the polygon area as the infiltration area in the model.
I thought that maybe because in the 2nd project, as I modeled the real survey data and the surface is completely complex, considering the polygon, with for example 8 vertices, could not matched and covered exactly the complex surface, and it does not consider the infiltration for that area!
If my guess is true, so what should I do in this regard to define a specific area for the infiltration for real survey data? What is the problem?
I look forward to hearing from you
Sincerely