FISH function for elastic modulus increment with confining pressure

Hi all,

I’d like to initialize a non linear distribution of elastic moduli in my FLAC slope model. In particular, I would like to vary the moduli according to the confining pressure (sig2).
I’m therefore trying to write a fish function called “linear_mod_z” but I cannot understand why it’s not working.
It seems that the script does read the sig2(i, j) value.

Here is the script of the function:


def linear_mod_z
	loop i (1,izones)
	  	loop j (1,jzones)
			if z_group(i,j) = 'clays'  then
				bulk_mod(i,j) = (_Km * sig2(i, j) + _Kq) ; Bulk_modulus
				shear_mod(i,j) = (_Gm * sig2(i, j) + _Gq) ; Shear_modulus
			endif
		endloop
	endloop
end

set _Km = 38.517 _Kq = -3.3236 _Gm = 23.11 _Gq = -1.9941

linear_mod_z

I’m using FLAC v.8.

Can anyone tell me where I am wrong?

Thanks a lot in advance.

There is no such intrinsic fish function sig2(), you have to calculate the intermediate principal stress based on the stress components, see ps3d.fis from the FLAC installation folder: Itasca\FLAC810\Datafiles\Fish\3-Library\Ps3d

Thanks a lot jwang! I will have a look at the suggested documentation.