Injection is defined as the grouting of fluidized materials into voids of the ground or spaces between the ground and adjacent structure, generally through bore holes and under pressure. For many engineers, injection is still considered an art rather than a science. Therefore, its successful application requires a great deal of experience, thorough knowledge of geological conditions, and an awareness of equipment capabilities and limitations. This paper describes a new approach to modeling injecting domain based on a non darcian flow and theory of consolidation. The proposed model utilizes the variation of the coefficient of permeability with respect to distance to bore hole axis to achieve a non-Darcian flow characteristics below certain hydraulic gradients. The potential of the proposed model is evaluated in prediction the extension of grouting for a single injection bore hole. The general comparison indicates that this approach is capable of solving injection boundary value problems and predict the extension of each grouting bore hole. A simple rule based on the percentage of overlapping two domains affected by two side by side injections bores is led to carry out the effective thickness of insolated cut-off wall. Accordingly, the priority of first injection bore hole and the provided impermibility of corresponding domain and the interaction of the second domain with the previous have been considered. This simple rule can lead the solution to carry out an average effective thickness of insolated wall upon the proposed model.
Generally, grouting is terminated either when a defined grouting pressure is obtained, or when the capacity of the available pump does not allow an additional increase. However, it can be assumed that the thin sections in porous media display homogeneous cement stone with dewatering canals, which are filled with the solid particles floated in grouting materials.