Many people are under the mistaken impression that pressure grouting under pools for soil and Pool stabilization is not practical because of all of the risk of damaging pipes below the pool. Many pools built today have a very low tolerance for movement of the pool after it is built because of the negative edge water features that require a high degree of levelness.
Our team at Arizona Foundation Solutions have overcome the obstacles required to safely grout pools and accomplish the mission objectives and have been doing so for many years. As of this date we have not damaged any plumbing while grouting underneath any pools. How do we do it? There are several basic steps:
- First we locate all of the reinforcing in the pool shell using GPR location methods.
- We then core shelf itself in areas to avoid the rebar reinforcing and any obvious typing in the surface of the pool itself.
- We then pothole to a 2 foot depth to ensure that we do not damage any existing piping infrastructure.
- We then drive our casing to a depth where we encounter refusal which would be also solid enough support the loads of the pool.
- We grout using a low mobility compaction grouting mix as opposed to an intrusion grouting mix that reduces the chance of the grout traveling to pipes.
In my earlier post Grouting Smoke and Mirrors Part III, Compaction Grouting, I discuss the various between compaction grouting and thin cement grouting. These refer to that for a more in-depth discussion on the rheology of grout mixes. Successful low mobility grout mixes by definition are designed to reduce travel once they are injected into the soil. This not only helps reduce soil fracturing and increase successful soil densification but they also reduce the risk of traveling. This is especially important in grouting under pools with a high amount of pipe infrastructure underneath.
Our teams here at Arizona Foundation Solutions have grouted many pools successfully by stabilizing them and raising them as needed for proper performance including pools with negative edges.