Page:4SIGHT manual- a computer program for modelling degradation of underground low level waste concrete vaults (IA 4sightmanualcomp5612snyd).pdf/121

39. INITIALIZE PARAMETERS|B.20 crackspacing = 2.0; } if(neutral_axis_depth.is_default $$\equiv$$ FALSE) crack-depth = sample_length - neutralaxis_depth.value if(crack-width.value > 0.0) printf("\"CRACK = %8.5lf AT %.8.51lf DEPTH u %8.5lf\"\n",     crack-width .value crack-spacing crack-depth ); if(joint-permeability > 0){ printf("\"J0INT PERM = %,8.1le\"n",joint-permeability); printf("\"J0INT=%8.5lf AT %8.5lf UNTIL %8.5lf\"\n",joint-width, joint-spacing,        joint-lifetime /365); }

This code is used in section 41.

48. Once the parameter $$D_0$$ has been established, the value of \eta for each ion must be initialized.

⟨Initialize ion ‘eta’ parameter 48⟩ $$\equiv$$ for (i = 0; i < num.cations; i++) cation[i].$$\eta$$ = cation[i].$$D_f/D_0$$ for (j = 0; j < num.anions; j++) anion [j].$$\eta$$ = anion[j].$$D_f/D_0$$

This code is used in section 41.

49. The presence of cracks is reflected in $$\kappa$$ which a multiplicative adjustment for permeability.

In the absence of cracks $$\kappa$$[i]=1. The quantities crack_width and crackspacing are specified by the user.

The equation for the permeability of cracks of width w spaced a distance a apart is

$$k=\frac{w^3}{12a}$$

(Calculate crack and joint adjustment to permeability 49) crack_permeability = (SQR(crack-width .value ) / 12); x = 0;   /* x starts from inside surface */ dx = sample-length/NUM_CELLS; for ( k = NUM_CELLS -1; k$$\ge$$0;k--) x += dx; if (x$$\le$$crack_depth) { $$\kappa$$[k] = $$k_0$$ * (1.-(joint_width/joint_spacing)-(crack_width.value/crack_spacing)); /*weighted length $$\kappa$$[k]+=joint_permeability * (joint_width/joint_spacing); $$\kappa$$[k]+=crack_permeability * (crack_width/crack_spacing); }    else { if ( x - dx < crack_depth) {  /* crack ends in this cell */ $$\kappa$$[k]=$$\kappa_0$$ * (1.-(joint_width/joint_spacing)-(crack_width.value/crack_spacing)); $$\kappa$$[k]+=joint_permeability * (joint_width/joint_spacing); $$\kappa$$[k]=(x-crack_depth)/$$\kappa$$[k] $$\kappa$$[k]+=(dx-(x-crack_depth))/crack_permeability*(crack_width.value/crack_spacing));         $$\kappa$$[k]/=dx          $$\kappa$$[k]=1.0/$$\kappa$$[k];        }        else {