I have tried to get the dispalcement variation with time of a unit cell model of sof clay improved my cement columns. I am getting the displacement curve but the slope of the displacement curve changes beyond a point. Not sure why this happens. I have used the creep parameters same as that of the example problem given in flac.
I have also attached the curve and the code for reference.
Kindly let me know what has to be modified.
Dat file:
model new
model title “coupled_06”
model large-strain off
fish automatic-create off
model configure fluid creep
;
zone create cylinder point 0 (0,0,0) point 1 (1.275,0,0) point 2 (0,5,0) point 3 (0,0,1.275) size 6 5 6 group ‘soil’
zone group ‘column’ range cylinder end-1 (0 0 0) end-2 (0 5 0) radius 0.425
zone face skin
zone cmodel assign soft-soil-creep range group ‘soil’
zone property density 617 lambda-modified 0.095 kappa-modified 0.015 range group ‘soil’
zone property poisson 0.33 friction 1 range group ‘soil’
zone property index-creep 0.0076 time-reference 2200 range group ‘soil’
zone property void-initial 3.3 range group ‘soil’
zone property stress-1-eff -20e3 stress-2-eff -10e3 stress-3-eff -10e3 range group ‘soil’
zone cmodel assign m-c range group ‘column’
zone property bulk 120e5 shear 46e5 cohesion 32e3 friction 1 poisson 0.33 range group ‘column’
zone property density 629 range group ‘column’
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 initialize stress-xx -10e3
zone initialize stress-yy -20e3
zone initialize stress-zz -10e3
; — fluid flow model —
zone fluid cmodel assign isotropic
zone fluid property permeability 1.62e-10 porosity 0.76 range group ‘soil’
zone fluid property perm 4.04e-10 poro 0.76 range group ‘column’
zone gridpoint initialize saturation 1.0
zone gridpoint initialize fluid-modulus 2e8
zone gridpoint initialize pore-pressure 0
zone initialize fluid-density 1e3
;
model fluid active off
model creep active off
; apply load
zone face apply stress-yy -100e3 servo ramp minimum [1.0/11] range position-y 5
model solve ratio 1e-7
model save ‘coupled_06_initial’
;
fish define set_creep
command
model creep timestep starting 1e-16
model creep timestep automatic
model creep timestep minimum 1e-16
model creep timestep maximum 1000
end_command
end
; — histories —
model history fluid time-total
zone history name ‘soil’ pore-pressure position ( 0.676171, 0, 0.676171)
zone history name ‘mid’ pore-pressure position ( 0.243961, 0, 0.588973)
zone history name ‘middle’ displacement-y position ( 0.676171, 5, 0.676171)
zone history name ‘soil corner’ displacement-y position ( 0.243961, 5, 0.588973)
;
model fluid active on
model fluid time-total 0.0
;
model creep active on
model creep time-total 0.0
;
zone face apply pore-pressure 0 range position-y 5
;
[set_creep]
model solve fluid time-total 8e6
model save ‘coupled_06_end’