A simple tip for PLAXIS3D, especially for those who are using old versions. Have you wondered how to model Tapered Piles or Conical volume with interface elements? Please try the code below (you can simply paste it as a whole in the Expert Macro Library, or paste it line-by-line into the commands line) this has to be the very first thing in your model (this is for old version where you have trinagulated geometry):

Cone R H 50 X Y Z 0 0 -1

_polycurve X Y-R Z-L 1 0 0 0 1 0

_Reset Polycurve_1 "Arc" 0 360 1

_Set Arcproperties_1.Radius R

_Surface Polycurve_1

_intersect (Surface_1 Polygon_1)

_delete (Surface_5)

_delete (Volume_1)

_delete (Surface_3)

_neginterface Surface_2

_neginterface Surface_4

_polycurve X Y-R Z 1 0 0 0 1 0

_Reset Polycurve_2 "Arc" 0 360 1

_Set Arcproperties_2.Radius R

_Surface Polycurve_2

Replace (R, H, X, Y, Z, L) with your values. Also, replace the substitution with the result value (for Y-R, and Z-L). All parameters defined in the photo. Don't assign a material to the surfaces, and after meshing you can assign any material required to the volume inside the cone. Try it and let me know if you have any issues, please ;D

Hamzah M. B. Al-Hashemi, A.M.ASCE

Civil / Geotechnical Design Engineer, MSc