Sand Slurry Injection: An Alternative Remediation for Special Projects

Subsurface sand slurry injection was initiated as an alternative to concrete grout injection, which is widely used across Florida to stabilize subsurface sinkhole activity or otherwise unstable subsurface conditions. Instead of pumping concrete grout under pressure, a sand slurry mixture is utilized. The sand slurry injection method provides for subsurface stabilization in the same way as concrete grout injection, but it also provides other benefits that are not possible to achieve with the concrete grout method. The injected sand slurry provides for long term stable subsurface conditions as well as anticipated effective permeability through the repaired subsurface. The sand slurry injection also avoids "grouting in" of buried utilities or other underground structures. The injection of natural sand to repair subsurface unstable conditions does not require introduction of hardening and effectively impervious material (cement), the application is simpler than concrete grout, and the cost is significantly less than the concrete grout alternative. The method of sand slurry injection is not intended as a blanket alternative to concrete grout injection, however, it can be a more advantageous method for special projects. The sand slurry method has been proven to be effective for filling large sinkhole cavities, raveled subsurface conditions below storm water ponds, sinkhole related collapses of roads, stabilization of storm water structures, and sinkhole activity created by pumping wells.