Hello everyone and @itascan
I am modeling a staged MSE wall constructed lift-by-lift on a deformable foundation soil in FLAC3D. When the MSE wall is modeled alone, the first lift converges quickly. However, once the foundation soil is included and equilibrated first, the first wall lift does not reach equilibrium even after very long run times (1+ hour). For each newly activated lift, I initialize stresses only in the new zones using zone initialize-stresses ratio 0.50 range group 'Soil_L01'. I also reset the state variables for the newly activated zones using zone initialize state 0, zone gridpoint initialize displacement (0,0,0), and zone gridpoint initialize velocity (0,0,0). Despite this, convergence remains extremely slow when the foundation soil is present. I am attaching a figure showing the first lift constructed on top of the foundation soil, for reference.
In addition, I am facing a second issue related to the wall–foundation interface. The wall base is intended to interact with the foundation soil (not fixed), but FLAC3D reports “No faces fell within the range” and “No valid interface nodes in range”, ”No groups assigned to Zones.”, even though the wall base and foundation top coincide at z = 0. Below is the exact approach I am using to define the interface: Note that foundation soil and wall are created as two separate bricks (even if touch at z=0).
; Foundation soil volume
zone group 'FoundationSoil' range position-z 0 -12.19
; Generate external faces
zone face skin
; Group the foundation top faces under the wall footprint (at z = 0)
zone face group 'FdnTop_Footprint' range position-z 0.0 position-x 12.19 24.39 position-y 12.19 21.334
; Group the wall base faces for lift 1 (also at z = 0)
; Lift-1 zones occupy z = 0 → 0.3048, so their base faces are at z = 0
zone face group 'WallBase_L01' range position-z 0.0 position-x 12.19 24.39 position-y 12.19 21.334
; Create wall–foundation interface using FACE groups
zone interface 'WallFoundation' create by-face separate range group 'FdnTop_Footprint' group 'WallBase_L01'
; Assign interface properties
zone interface node property stiffness-normal 5.0e7 stiffness-shear 5.0e7 ...
friction 30 cohesion 8740 range group 'WallFoundation'
However, FLAC3D still does not detect a valid interface.
I would appreciate guidance on (1) the correct way to handle staged construction on an already equilibrated foundation, particularly regarding convergence of early lifts, and (2) best practices for ensuring wall–foundation interfaces are correctly recognized, including any requirements related to face alignment, grid separation, or staging sequence.
Thank you for your help.
