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$\geq$0;k--)
    x += dx;
    if (x$\leq$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 {