Zone initialize-stresses overburden FLAC3D Command

FLAC3D
1

Dear All,

Has anyone had issues when using the zone initialize-stresses overburden command?

I have set up a simple model representing a 100m x 100m x 100m block with a surcharge of 100m on top considering 20kN/m3 of unit weight as an example:

model new
;
zone create brick &
point 0 0,0,0 &
point 1 100,0,0 &
point 2 0,100,0 &
point 3 0,0,100 &
size 25 25 25 &
rat 1 1 1 &
group ‘Block’
;
model gravity 0 0 -10.0
;
zone cmodel assign elastic
zone property density 2000 young 2000.0e6 poisson 0.2
;
zone gridpoint fix velocity-z range position-z -0.10 0.10
zone gridpoint fix velocity-x range position-x -0.10 0.10
zone gridpoint fix velocity-x range position-x 99.90 100.10
zone gridpoint fix velocity-y range position-y -0.10 0.10
zone gridpoint fix velocity-y range position-y 99.90 100.10
;
zone initialize-stresses overburden -2.0e6 ratio 1.0
;
model large-strain off
model cycle 1000
model solve ratio 1.e-8
;
program return

The model works fine if I consider the traditional FISH function to set up the stresses but I am not getting the expected results with this command. I might have missed something.

I would be most grateful for your views on this.

Thank you so much.

2

Since there is an overburden load, there should have a corresponding apply there, e.g.,

zone face apply stress-normal -2.0e6 range position-z 100

3

Thank you so much for your prompt response and clarification.

My apologies, I misunderstood the explanation in the Manual, as I thought including the overburden load directly as input in zone initialize-stresses overburden -2.0e6 ratio 1.0 would account for that directly.