Dear Itasca Team,
I am working on consolidation problem of the soft soil improved by columns. For the mc model and its properties, when I am solving for the initial undrained condition, I am getting negative pore pressure. But Ideally it has to be maximum positive pore pressure. I have attached my code along with this. Kindly let me know you opinion. I am sure all the property values are correct to my knowledge.
Dat file:
model new
model large-strain off
model title ‘uc2’
model configure fluid
zone create cylinder point 0 (0,0,0) point 1 (1.275,0,0) point 2 (0,10,0) point 3 (0,0,1.275) size 6 10 4 group ‘soil’
zone group ‘column’ range cylinder end-1 (0 0 0) end-2 (0 10 0) radius 0.425
zone property density 617 range group ‘soil’
zone property density 629 range group ‘column’
zone attach by-face
; — mechanical model —
zone cmodel assign m-c
zone property bulk 36e5 shear 13e5 cohesion 20e3 friction 1 poisson 0.33 range group ‘soil’
zone property bulk 120e5 shear 46e5 cohesion 32e3 friction 10 poisson 0.33 range group ‘column’
zone face skin
zone face apply velocity-z 0 range group ‘bottom’
zone face apply velocity-x 0 range group ‘west’
zone face apply velocity-x 0 range group ‘east’
zone face apply velocity-z 0 range group ‘east’
zone face apply velocity (0,0,0) range group “south”
zone face apply stress-normal = -0.1e6 range position-y 10
; — fluid flow model —
zone fluid cmodel assign isotropic
zone gridpoint initialize fluid-modulus 9e8
; — pore pressure fixed at zero at the surface —
zone gridpoint fix pore-pressure 0 range position-y 10
; — settings —
model fluid active off
zone fluid fastflow on
; — timing —
model solve convergence 1
model save ‘uc2_initial’
; — turn on fluid flow model —
zone fluid property perm 1.62e-10 poro 0.76 range group ‘soil’
zone fluid property perm 4.04e-10 poro 0.76 range group ‘column’
;zone fluid property perm-xx 3e-10 perm-yy 1e-10 perm-zz 3e-10 range group ‘column’
model fluid active on
zone gridpoint initialize velocity (0,0,0)
zone gridpoint initialize displacement (0,0,0)
; — set mechanical limits —
model mechanical substep 100
model mechanical follower on
model fluid substep 10
; — histories —
model history fluid time-total
zone history name ‘pp1’ pore-pressure position (0,0,0)
zone history name ‘pp2’ pore-pressure position (0,0,1.275)
zone history name ‘disp1’ displacement-y position (0,10,0)
zone history name ‘disp2’ displacement-y position (0,10,1.275)
model solve fluid time-total 8.7e6
model save ‘uc2_end’