The process of grouting involves injecting materials into the soil to stabilize it. Cement grouts injected around the bases of structures help stabilize the soil around the object. Referred to as foundation grouting, this procedure is often used to stabilize the base or foundation of dams. The procedure involves heavy mechanized equipment that drills holes and injects the grout into the soil.
Grout fills any voids in the soil, reducing the soil's water permeability. Instead of having a network of open spaces between the soil particles, the grout stops the water flow. This also adds structure to the soil, increasing the stability of the surface. A series of grout holes delivers the benefits of the grout to a larger area. The permeability of the soil determines the depth and placement of the holes.
Types of Grout
Cement is just one type of grout. Other forms include sands, clays or chemicals that react with the soil. Again, the soil type determines the most effective grout. Injecting the grout requires using the right amount of pressure for the material and soil. Too much pressure forces the ground up, while too little pressure will not fill the voids in the soil. Because the grout forms around the bottom of the pipe, the grouted soil is referred to as a "grout bulb" because of its shape.
A grout curtain is a type of foundation grouting used on dams. A series of holes is drilled in multiple rows along the base of the dam. Grout is injected into these holes to form a waterproof curtain. This prevents water seepage through the base of the dam, which can damage the dam's integrity.
Chemical and physical tests reveal the presence of grout in the soil. Soil on the backside of the grout curtain is monitored for leaks through the foundation.
Keith Allen, a 1979 graduate of Valley City State College, has worked at a variety of jobs including computer operator, medical clinic manager, radio talk show host and potato sorter. For over five years he has worked as a newspaper reporter and historic researcher. His works have appeared in regional newspapers in North Dakota and in "North Dakota Horizons" and "Cowboys and Indians" magazines.