# Rigid Voronoi slope model collapse

I generated a voronoi model in UDEC 6 and made the blocks rigid. When I try to solve it, the block just collapse downwards as shown in picture. I have already applied zero velocity on the lower boundaries. I have also sent the code. Can anyone tell me how I stop this phenomenon. Thank you.

round 0.2
edge 0.4
block 0,0 0,300 100,300 476,100 576,100 576,0
vor edge 10
change mat 1 range -29.3828,605.9828 -14.9911,320.9908
property mat 1 density 2.654E3
group joint ‘weakj:ID104’ range -31.7827,611.3825 -39.5897,334.19
joint model area jks 2E5 jkn 2E8 jfriction 25 range group ‘weakj:ID104’
boundary xvel 0 yvel 0 range -28.7829,628.1816 -11.3913,2.408
boundary xvel 0 yvel 0 range 575.9844,603.5829 -43.1895,144.0003
boundary xvel 0 yvel 0 range -22.1832,1.2155 -22.1907,327.5904
set gravity=0.0 -9.81
solve

Use [In Situ] → [Fix] for the boundaries; The jkn is not stiff enough and causing overlapping. I added an order on it.

round 0.2
edge 0.4
block 0,0 0,300 100,300 476,100 576,100 576,0
vor edge 10
change mat 1 range -29.3828,605.9828 -14.9911,320.9908
property mat 1 density 2.654E3
group joint weakj:ID104 range -31.7827,611.3825 -39.5897,334.19
joint model area jks 2E5 jkn 2E9 jfriction 25 range group weakj:ID104
;boundary xvel 0 yvel 0 range -28.7829,628.1816 -11.3913,2.408
;boundary xvel 0 yvel 0 range 575.9844,603.5829 -43.1895,144.0003
;boundary xvel 0 yvel 0 range -22.1832,1.2155 -22.1907,327.5904
fix range -11.8351,585.3726 -9.9694,8.2065
fix range -11.8351,9.1104 -23.1859,308.801
fix range 571.4983,584.0657 -9.5713,108.771
set gravity=0.0 -9.81
solve

2 Likes

@jscic Thanks a lot. And I had some other questions regarding this model. This time I use the same slope model but using Mohr-coulomb deformable blocks. There is sometimes the overlapping errors (when stiffness are low or near to the young’s modulus), so I increase the stiffness as the software says, but the more I increase the stiffness, the model becomes more stronger and reduces the block deformations I want to see. What I want to see is like the voronoi blocks slide off or roll off as rockfall or slide off the slope like this paper I send below (like toppling or sliding). Can you give me some suggestions on I can achieve this. Thank you.

Paper:
s00603-019-01855-z.pdf (4.6 MB)

My code:

round 0.02
edge 0.04
block 0,0 0,300 100,300 476,100 576,100 576,0
vor edge 10
gen edge 100.0 range region (-25.6195,-47.4439) (-25.6195,319.6272) (633.2542,319.6272) (633.2542,-47.4439)
group zone ‘User:ID143’ range -20.3834,616.7823 -41.3897,325.7905
zone model mohr density 2.654E3 bulk 1.66667E8 shear 7.69231E7 friction 29 cohesion 8.4E4 range group ‘User:ID143’
group joint ‘weakj:ID104’ range -55.7815,604.183 -33.5901,343.1896
joint model area jks 2E5 jkn 2E9 jfriction 25 range group ‘weakj:ID104’
boundary xvel 0 yvel 0 range -20.1652,601.074 -15.8092,2.7352
boundary xvel 0 yvel 0 range 573.8027,637.072 -40.3533,153.818
boundary xvel 0 yvel 0 range -33.2554,2.7427 -7.0824,319.6272
set gravity=0.0 -9.81
solve

One of the Apply Examples in the Itasca’s website should give you a great idea. Please check the link:

https://www.itascacg.com/software/support/examples/rockslide-runout-prediction

I am trying to re-produce this code in UDEC 7, I made little changes but still does not work,
Here is my code:

;
model new
round 0.02
edge 0.04
block create polygon 0,0 0,300 100,300 476,100 576,100 576,0
vor edge 10
gen edge 100.0 range region (-25.6195,-47.4439) (-25.6195,319.6272) (533.2542,319.6272) (533.2542,-47.4439)
group zone ‘ID1’ range -20.3834,516.7823 -41.3897,325.7905
zone model mohr density 2.654E3 bulk 1.66667E8 shear 7.69231E7 friction 29 cohesion 8.4E4 range group ‘ID1’
group joint ‘weakj1’ range -55.7815,604.183 -33.5901,343.1896
joint model area jks 2E5 jkn 2E9 jfriction 25 range group ‘weakj1’
boundary xvel 0 yvel 0 range -20.1652,601.074 -15.8092,2.7352
boundary xvel 0 yvel 0 range 573.8027,637.072 -40.3533,153.818
boundary xvel 0 yvel 0 range -33.2554,2.7427 -7.0824,319.6272
set gravity=0.0 -9.81

Cycle 1

The entire command set has changed in UDEC 7. The commands you have listed are UDEC 6 commands (not UDEC 7 commands). There is an automatic command conversion tool in UDEC 7. Load the file into a text pane and press edit->command conversion.

this is the updates now but i still have a problem with this line (block zone generate edge 100.0 range region -25.6195 -47.4439 -25.6195 319.6272 533.2542 319.6272 533.2542 -47.4439)

;
;
model new
block tolerance corner-round-length 0.02
block tolerance minimum-edge-length 0.04
block create polygon 0 0 0 300 100 300 476 100 576 100 576 0
block cut voronoi edge-maximum 10
block zone generate edge 100.0 range region -25.6195 -47.4439 -25.6195 319.6272 533.2542 319.6272 533.2542 -47.4439
block zone group ‘ID1’ range position-x -20.3834 516.7823 position-y -41.3897 325.7905
block zone cmodel assign mohr-coulomb density 2.654E3 bulk 1.66667E8 shear 7.69231E7 friction 29 cohesion 8.4E4 range group ‘ID1’
block contact group ‘weakj1’ range position-x -55.7815 604.183 position-y -33.5901 343.1896
block contact cmodel assign area stiffness-shear 2E5 stiffness-normal 2E9 friction 25 range group ‘weakj1’
block gridpoint apply velocity-x 0 velocity-y 0 range position-x -20.1652 601.074 position-y -15.8092 2.7352
block gridpoint apply velocity-x 0 velocity-y 0 range position-x 573.8027 637.072 position-y -40.3533 153.818
block gridpoint apply velocity-x 0 velocity-y 0 range position-x -33.2554 2.7427 position-y -7.0824 319.6272
model gravity 0.0 -9.81
;
block cycle 1
;
return
;

1. The quote marks (‘ID1’ ) you are using for strings are not accepted by UDEC. For example use ‘ID1’ instead.
2. You need to add a seed command to the block cut voronoi command (I used seed 10010), Otherwise you will get a different model every time you run the data file. That makes it impossible to repeat or debug.
3. You need to reduce the edge length in the block zone gen edge command to 7.0.
4. You still have rigid blocks outside of the block zone gen range. You have not assigned properties to these blocks. The model will not cycle.

I see that the forum is changing the quote marks that are displayed in the listings. You need to use the single quote marks that are to the left of the enter key.

I think I also do not employ this properly (block cut voronoi command (I used seed 10010),)

model new
block tolerance corner-round-length 0.02
block tolerance minimum-edge-length 0.04
block create polygon 0 0 0 300 100 300 476 100 576 100 576 0
block cut voronoi edge-maximum 10 seed 10010
block zone generate edge 7.0 range region -25.6195 -47.4439 -25.6195 319.6272 533.2542 319.6272 533.2542 -47.4439
block zone group ‘ID1’ range position-x -20.3834 516.7823 position-y -41.3897 325.7905
block zone cmodel assign mohr-coulomb density 2.654E3 bulk 1.66667E8 shear 7.69231E7 friction 29 cohesion 8.4E4 range group ‘ID1’
block contact group ‘weakj1’ range position-x -55.7815 604.183 position-y -33.5901 343.1896
block contact cmodel assign area stiffness-shear 2E5 stiffness-normal 2E9 friction 25 range group ‘weakj1’
block gridpoint apply velocity-x 0 velocity-y 0 range position-x -20.1652 601.074 position-y -15.8092 2.7352
block gridpoint apply velocity-x 0 velocity-y 0 range position-x 573.8027 637.072 position-y -40.3533 153.818
block gridpoint apply velocity-x 0 velocity-y 0 range position-x -33.2554 2.7427 position-y -7.0824 319.6272
model gravity 0.0 -9.81
;
block cycle 1

1 Like

Thank you very much

I had some error in the text and now this is fixed and people can use it.

;
model new
;
block tolerance corner-round-length 0.02
block tolerance minimum-edge-length 0.04
;
block create polygon 0 0 0 300 100 300 476 100 576 100 576 0
;
block cut voronoi edge-maximum 10 seed 10010
;
block zone generate edge 7.0 range region -25.6195 -47.4439 -25.6195 319.6272 633.2542 319.6272 633.2542 -47.4439
block zone group ‘ID1’ range position-x -20.3834 616.7823 position-y -41.3897 325.7905
;
block zone cmodel assign mohr-coulomb density 2.654E3 bulk 1.66667E8 shear 7.69231E7 friction 29 cohesion 8.4E4 range group ‘ID1’
;
block contact group ‘weakj1’ range position-x -55.7815 604.183 position-y -33.5901 343.1896
;
block contact cmodel assign area stiffness-shear 2E5 stiffness-normal 2E9 friction 25 range group ‘weakj1’
;
block gridpoint apply velocity-x 0 velocity-y 0 range position-x -20.1652 601.074 position-y -15.8092 2.7352
block gridpoint apply velocity-x 0 velocity-y 0 range position-x 573.8027 637.072 position-y -40.3533 153.818
block gridpoint apply velocity-x 0 velocity-y 0 range position-x -33.2554 2.7427 position-y -7.0824 319.6272

;
model gravity 0.0 -9.81
;
;model cycle 1
model solve

Also, I am a 3DEC license owner, shouldn’t I will be able to run this model for a few cycles? does not even allow me to run it for one cycle

Mohsen,

A 3DEC license does not allow you to use UDEC and vis versa. They are not the same product.

In demo mode you can run small models. But this is much larger than that.