Chemical Grouting - Sinkhole Repair

There are generally two types of chemical grouting:

Permeation Chemical Grouting

Form a stone-like material similar to sandstone by injecting polyurethane based grout into granular soil under pressure. The chemical grout material permeates the soil and solidifies to increase the strength of the stratum and its load bearing characteristics. This method is especially effective in shallow soils.

The process of Permeation Chemical Grouting involves drilling a hole and grouting in a sleeve port pipe.  This pipe has holes along its length, and the thin grout is injected under pressure to permeate the soil and harden the granular soil into a solid mass.  The resulting soil is not as permeable by water, and it is much stronger for support.  It may be used to strengthen existing foundations or for other reasons that help in a construction process.  Sometimes chemical grouting is used around tunneling operations to strengthen nearby soils.

Expansive Chemical Grouting

The second type is the injection of expansive foam that fills voids and can be used to lift and re-level slabs and sometimes foundations.