Pressure grouting is commonly used to fill voids under slabs, in open cracks or into broken rock to either consolidate the matter or to make the area more stable. Grout is mixed by specialized grout plants that have the ability to convey and place the grout under pressure. The grout is conveyed through special grout line to the grouting location where it is either openly poured into the void or pumped through some sort of packer. The volume and pressure of the grout is recorded while being injected. Often this method can be used to lift steeled slabs and foundations to former elevations. This must be monitored or severe damage can occur to existing structures.
Often pressure grouting is used to fill cracks and voids in settled earth. This helps consolidate the unstable earth and also seal cracks to prevent water from penetrating into the deeper structures.
Grout curtains are excellent solutions to retaining water and consolidating ground. Grout curtains are often used on projects that require an excavation in close proximity to standing or flowing water. A pattern of holes are laid out between the excavation and the water body by a surveyor. These holes are then drilled out and a packer system is lowered down the hole. Grout is mixed and conveyed through a tremy line to the packers. The grout is then injected into the substrate at controlled pressures and volumes. The grout is forced into the substrate creating a water impermeable barrier. The packers are often set at multiple elevations in the drill hole to allow for secondary and tertiary grouting applications. Grout curtains often significantly reduce the amount of water permeating through these zones and often seals them completely.
Norpac crew members have been involved with many pressure grouting and curtain grouting projects and are very familiar with all aspects of these unique operations.