Modeling of gel barrier formation by using colloidal silica in saturated media

The applicability of constructing a subsurface barrier by injecting a Colloidal Silica solution directly into the saturated medium was examined through numerical experiments. Investigations ascertain that the construction of this Colloidal Silica-based subsurface barrier in the saturated medium might be a promising containment technology. According to the results of numerical studies, gel formation takes place in the region were more than 90% of introductory concentration of the Colloidal Silica solution is maintained at a time equal to the gel-point. By using a point injection method, the radius of the solidified Colloidal Silica mass increases proportional to the respective ratios of the gel-points and the injection pressure heads. With higher injection pressures and longer gel-points, a larger volume of injected Colloidal Silica solution is diluted. The effect of subsurface water flow is significant when the solution has a slower gelation rate and the spherical shape of the solidified mass is less distorted with increasing injection rate. The degree of distoration of the solidified Colloidal Silica mass is much less than that of the rest of the Colloidal Silica solution surrounding the solidified Colloidal Silica mass