Basic Soil Stabilization
Basic soil stabilization concepts are very clearly explained in the blog post Polyurethane Soil Stabilization Explained...
Unstable soil can be defined as soil that will not stay in place on its own, and therefore requires extra support. It should be noted that unstable soil can threaten the stability, security, and safety of infrastructure and can damage, degrade, and even destroy a number of structures, such as buildings, bridges, and roads.
Soil can be stabilized with high strength polyurethane foam. Once the bearing capacity of the soil has been increased with this process, then the structure can be lifted if necessary. Read more and watch an educational Soil Stabilization animation.
Deep Soil Stabilization
Sometimes unstable soil issues are located deep beneath the surface the endangered structure. This problem calls for a specialized repair process, which is explained in the blog post Deep Soil Stabilization in Metro Atlanta...
Sometimes soil issues occur well below the surface. If the problem is five feet deep or more, then deep soil stabilization is required. GCS technicians detect the depth of soil issues with a soil probe during the standard site evaluation process. Further investigation is available via soil testing probes and ground penetration radar.
The deep soil stabilization process consists of injecting high strength polyurethane resin through long sections of hydraulic tubing. Injection starts from bottom and the technician injects more as the tubing is extracted, creating solid columns of soil stabilization resin. Read more.
Causes of Unstable Soil
There are a variety of factors that can cause unstable soil including erosion, poor compaction, freeze/thaw cycles and decomposition. For more on the causes of unstable soil, see this multi-part blog series:
The Causes of Unstable Soil - A Brief Overview
The Causes of Unstable Soil - Erosion
The Causes of Unstable Soil - Poor Compaction
The Causes of Unstable Soil - Freezing and Thawing
The Causes of Unstable Soil - Decomposition