What types of structures and construction activities can groundwater impact?
Groundwater movement can cause erosion, which eventually leads to issues with sub grade infrastructure systems. When the soil around a structure erodes away, the structure can shift and settle. This can result in a compromised pipe that allows groundwater to flow into it. This process is known as Inflow and Infiltration, commonly referred to as I&I.
I&I is an expensive problem to have. The water leaking into the pipe can increase treatment costs, bring soil in that blocks pipes, can overburden the sewer system’s capacity, and cause erosion around pipes, lateral lines, culverts, and manholes. If erosion is occurring, the structure can settle and fail, causing a cascade of failures along the adjacent pipes and above structures.
Heavy amounts of groundwater can cause other issues, such as infiltration into trenches, utility vaults, and tunnels. We have seen and been a part of many projects that were directly focused on preventing groundwater infiltration into these types of structures.
With trenches for new utility systems, another issue has been the infiltration of contaminated groundwater into the trench. This issue is an expensive one, because not only do you need to deal with dewatering, but you have environmental issues as well, which require treatment, environmental specialists, and stringent regulatory oversight.
How can Polyurethane Chemical Grout Help?
Polyurethane chemical grouts are a valuable tool for helping solve all of these groundwater related issues. Injecting chemical grout into soils is an excellent way to densify and compact the soil to help prevent erosion and seal against I&I. This works due to the chemical grouts' expansive nature.
When a chemical grout, such as our EL-003, is injected into the soil layer, it initially enters the zone in liquid form. This helps ensure the polymer finds the path of least resistance and fills any loose soil areas or voids. Within a minute, the polymer reacts and begins to bond and expand throughout the soil media. With an expansion capability of up to 25 times its liquid volume, the polymer quickly fills the voids and densifies the soil around it. Consequently, the polymer also embeds itself into the structure's cracks and/or separated joints to prevent the groundwater from entering into the structure.
In the case of contaminants, we use a specialized approach called Deep Stratum Injection, or DSI. DSI works by injecting the polymer in a vertical and horizontal gridded pattern. The at-depth injections are made using metal rods that are driven to depth and allow us to directly inject the chemical grout into the target zones. The result, with proper design, is a highly dense matrix or chemical grout and soil that prevent the contaminated groundwater from migrating into the trench or into at-risk areas. The process has been proven to save hundreds of thousands of dollars in treatment costs and project delays.
Benefits of Polyurethane Chemical Grout in these Controlling Groundwater Migration
This is a dense topic that normally requires a whole write-up itself, so please forgive in advance if it feels rushed. Our EL-Polymers have many benefits for controlling groundwater migration and for rehabilitating compromised structures. Here is a quick list:
- Environmentally Inert. If you are going to inject any type of chemical into groundwater, you better be sure you aren’t going to contaminate it. Our polymers are environmentally inert and do not leach chemicals into the water. Additionally, they can come with NSF-61 certifications, meaning they are safe to come in contact with drinking water.
- Our polymers cure to 95% capacity within 25 minutes.
- Minimally Invasive. No trenching or excavation is involved here. We can install the polymers from within or above the structure. And because of the speed of the polymer, we can complete a project with minimal interruption to traffic flows or utility services.
In conclusion, polyurethane chemical grouts are an exceptional way to control groundwater migration, stabilize and rehabilitate infrastructure, and re-establish soil density within a single application. If you have an issue with groundwater impacting your infrastructure assets, we’d love to talk with you and find out if we can offer a solution.