HMI Deep Foamjection Pennsylvania Sink Hole

To evaluate the soils in and around the hole, tests were conducted using a Dynamic Cone Penetrometer (DCP). These tests revealed a drainage issue that was undermining the soils in the area. It was found that a sewer pipe and gutter drain were running parallel to where the weakest soils was found in the DCP tests and under a concrete walkway leading to the street. This created a voided channel that was about 7-10 feet wide and 35 feet long. As this was a brick road, there was no drainage system, resulting in every other house on the black having a small sink hole along the city walkway with collapsing bricks.

Being as this void was being caused by drainage issues, the contractor decided to use a hydro-insensitive foam and Deep Foamjection to fill the hole and stabilize the soils. HydroFoam was specially designed to resist hydrolysis, the chemical process of water breaking down a compound. Designed not only to set up in the presence of water, but to maintain dimensional stability, HydroFoam was the best solution for the job.

While injecting HydroFoam, the contractor used a rotary level to monitor for ground movement and used the DCP to verify an increase in the stability of the soils. The Deep Foamjection was done at two depths at each injection site to stabilize the soils. A total of 280 pounds of HydroFoam was used to gradually fill the hole and stabilize the soils over the course of about 5-6 hours. The following report shows the DCP tests done before and after the Deep Foamjection process.