Solving Soil Issues By Grouting
Compaction Grouting is a type of Pressure Grouting that densifies and compacts soil that is in need of stabilization.
For foundation repair it is usually and most effective in stabilizing non point load bearing structures such as swimming pools or flat pads and pavements such as an interior floor pad. It can be performed either top down or bottom up.
Most flat structures settle because of soil being too heavy to support itself. Ten feet of so of soil on top of a weak layer can cause it to compress.
The surface then follows the rest of the soil causing distress in the pavement, pool or any structure located above the problem.
The steps for typical bottom up compaction grouting are as follows:
1. First drive the injection casing to the proper depth. This can be done in one of several ways. The simplest is to hammer down the casing with an air powered driver or a hydraulic powered hammer. Sometimes when penetration through harder soils is required to reach unconsolidated soils pre-drilling is required. Usually with a down in the hole hammer. This is a common step that is often not followed with vigilance.
2. Once the proper dept has been reached. Grout is pumped down and injected. For Compaction grouting, a very stiff mix with in internal high friction is used. For true compaction grouting a 2” diameter or larger casing is required. Any casing less than 2”is not true compaction grouting. Grout pressure and volume should not be large enough to fracture the soil.
3. Once a volume, pressure or ground movement marker has been met, the casing is raised 12 to 24 inches and the same grouting process is repeated.
4. This grouting and lifting procedure is repeated until the surface is reached.
Compaction or slurry grouting is a process that should be done under the direct supervision of a licensed geotechnical engineer who is independent of the contractor. What pressures or volumes should each injection at a particular depth of soil be stopped at? Owners do not have the knowledge to make such decisions and contractors have too much conflict of interest to make those determinations. Geotechnical borings should be done in advance of any grouting to help the Engineer make sound decisions. The engineer should then inspect the process to insure that his parameters are followed and sign off and stamp the project on completion.
Arizona Ram Jack is the leading contractor for underpinning in the State of Arizona for several years now; and have helped thousands stabilize and raise their sunken foundations.
Maybe you are having issues with sink hoies or unstable soils? Arizona Repair Masons has been performing this technique for years now.
The process is similar in practice to slabjacking, however instead of grouting only under the slab or filling the hole we drive the tube to a predetermined depth, and pressure grout the weak soils making them more stable. This also can be beneficial to fill voids in very rocky soils that traditional piering may not be suitable for.
In order for this type of repair to be effective deep soil testing must be done by a competent soils testing engineer. An effective grouting plan can then be designed that will take into effect the various layers of soil and their densities to avoid injecting on top of loose soil and exacerbating the problem by adding weight on top of the incompetent soil.
We have successfully grouted pavements, building slabs, bridge approach slabs, house floors, pools and other simliar types of infrastructure. Our crew is talanted, hard working, and careful. As you run into soil problems of any type, please call and challenge us to bring you the right soultion to each problem.