Grouting methods aim to improve the engineering characteristics of a soil or rock mass. This is accomplished by modifying the mechanical properties as strength, stiffness and permeability. A liquid grout mix (suspension, solution or resin) is injected into the ground using tube-a-manchettes or grouting lances and penetrates into the pores and joints to fill them as completely as possible.
The grouted mix hardens in the soil/rock changing the properties of the grouted materials. Sealing or strengthening of the ground results from filling interconnected voids, and by sedimentation, filtration or chemical reaction of the grout mix with the ground depending on the rheological and strength properties of the grout.
TAM method is the most accurate way to place grout, also referred as sleeve port pipe. This are tubes (Metal or PVC) with small port holes drilled at regularly spaced intervals (0.3 to 1 m) to provide the desired grout stage length. The pipes are introduced into a predrilled hole and sealed with a weak grout.
For grout injection normally a double packer is used to isolate the valve that will be grouted. Injection pressure breaks the weak confining grout and expands the rubber sleeve so the grout is forced in to the ground at that particular valve location. The same valves can often be grouted more than once. In soils that do not run excessively steel sleeve pipes can be driven or pushed into place.
All the grouting parameters (flow rate, pressure, volume, time) are recorded during the grouting process, allowing a permanent control.