Converting code from version 5.2 to version 7

3DEC
1

Dear colleagues,

I have written a code in 3DEC version 5.2 for simulating fallout at deep underground mines. The code ran correctly on this version, and I then converted it to 3DEC version 7 using the same parameters. However, while the code on version 5.2 reached equilibrium after one day, the version 7 code did not after 1 week.
I assigned high-strength joint parameters before excavation for both models. once it reaches equilibrium, I will change the joint parameters to their real values before excavation. For ‘block contact material-table default prop’, I assigned real joint parameters or low-strength parameters for discontinuities.
I would appreciate any assistance in understanding why the version 7 code did not reach equilibrium.

2

Based on that small amount of information it is hard to guess what the problem might be. If you can share your data publicly, then please add more information. If it is more sensitive data, then send it to Itasca for inspection.

Some usual suspects:

  • some property names have changed, which maybe the autoconvert made a mistake on
  • same with boundary conditions, stress initialization etc.
3

Thanks

; model simple geometry

block create brick -250 250 -250 250 -250 250 group ‘Host rock’ ; joint id 1
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model restore ‘CF-G.3dsav’

model large-strain on
;
;-------------------Properties --------------------------------
block zone cmodel assign elastic
block zone property density 2900 young 70e9 poiss 0.27 bulk 50.7e9 shear 27.55e9
;----------------fictious joint---------------------------
block contact jmodel assign mohr
block contact property stiffness-normal 800e15 stiffness-shear 800e15 friction 60 tension 100e7 cohesion 100e7
;;----------------structural Joint 29 30 31 32 33 34---------------------------
;block contact jmodel assign mohr
;block contact property stiffness-normal 100e9 stiffness-shear 7e9 tension 0 cohesion 0 friction 35 range joint-set 29 30 31 32 33 34
;;----------------Fault Joint 16---------------------------
;block contact jmodel assign mohr
;block contact property stiffness-normal 100e9 stiffness-shear 100e9 tension 0.5e6 cohesion 0.5e6 ;friction 35 range joint-set 16
;;----------------default contact props---------------------------
block contact material-table default prop …
stiff-norm 100e9 stiff-shear 7e9 friction 35
;
;‘’ I tested by low strength parameters for ‘block contact material-table default prop’’
;----------------------------Gravity----------------------------------
model gravity 0.0 0.0 -9.81
;-------------------------------Insitu Stress-------------------------------
block insitu stress -65e6 -30e6 -32e6 0 5e6 0 gradient-z 0 0 0 0 0 0
;----------------------------Stress Boundary------------------------
block face apply stress -65e6,0,0 0 5e6 0 gradient-z 0 0 0 0 0 0 range pos-x -250.01,-249.99
block face apply stress -65e6,0,0 0 5e6 0 gradient-z 0 0 0 0 0 0 range pos-x 249.99,250.01
block face apply stress 0,0,-32e6 0 5e6 0 gradient-z 0 0 0.029e6 0 0 0 range pos-z -250.01,-249.99
block face apply stress 0,0,-32e6 0 5e6 0 gradient-z 0 0 0.029e6 0 0 0 range pos-z 249.99,250.01
block face apply stress 0,-30e6,0 0 0 0 gradient-z 0 0 0 0 0 0 range pos-y -250.01,-249.9
block face apply stress 0,-30e6,0 0 0 0 gradient-z 0 0 0 0 0 0 range pos-y 249.99,250.01

model solve ;convergence 1

4

It’s hard to tell for sure without the whole data file, but it looks like you have an initial stress state with some non-zero shear stresses. Since all of the boundaries are stress boundaries, it is possible (likely) that the whole block will rotate. If you have shear stresses, you probably want to fix at least one boundary to prevent this.

I would send the data file to technical support if this doesn’t solve it.