What is the best way to define the below 2D fish function in FLAC 3D that loops over all zones calculates Vs based on the vertical effective stress?
loop i (1,izones)
loop j (1,jzones)
if model(i,j) # 1
$sigv = -syy(i,j) - pp(i,j)
Vs = Vs1 * sqrt($sigv/2116)^n
shear_mod(i,j) = Vs^2 * density(i,j)
end_if
end_loop
end_loop
Something like this:
[global Vs1 = 500]
[global n = 0.25]
fish operator input_shear(z)
local pp = zone.pp(z)
local sigv = - zone.stress(z)->zz - pp
local Vs = Vs1 * (sigv/2116)^n
zone.prop(z,“shear”) = Vs^2 * zone.density(z)
end
[input_shear(::zone.list)])
Please check and make necessary modification for your model.
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Thank you for your response, @cheng. The provided code worked perfectly and the shear modulus vary in z direction. I have a follow-up question: after assigning the shear modulus using the code you provided, I would like to create a function that allows me to vary the shear modulus in both the x and y directions across the model. This is to assess the differential settlement resulting from a reduction in stiffness. I would greatly appreciate any guidance on how to iterate through zones within a single layer and update the shear modulus. In FLAC2D I would probably use something like below if it works:
loop $i (1,izones)
loop $j (1,jzones)
IF z_group($i,$j) = ‘Sand’ THEN
ex_1 ($i,$j) = z_prop($i,$j, ‘shear’)
z_prop($i,$j, ‘shear’) = ex_1 ($i,$j) * (linear reduction function!)
end_if
end_loop
end_loop
Something like:
fish operator adj_shear(z)
if zone.isgroup(z,“Sand”)
zone.prop(z,“shear”) *= 0.5
endif
end
[adj_shear(::zone.list)])
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