After nearly a decade, the Hoen Avenue embankment repair project is complete and at a significant cost savings using a deep polymer injection technology. The project was initiated when a section of the Matanzas Creek embankment collapsed along Hoen Avenue west of Farmers Lane.
In the early stages of the project, a preliminary engineering design to stabilize the embankment using piers, grade beams and roadway reconstruction was estimated to cost $1.8 million. The project was placed on hold due to lack of funding.
Over the years, city street crews have been maintaining the ongoing soil settlement caused by the embankment failure by filling the depressed areas of the roadway with asphalt and crack sealing. In 2017, the embankment experienced considerable settlement which resulted in closing the roadway to single lane traffic control.
In 2020, city staff learned of a low cost, less intrusive deep polymer injection technology. It was decided to apply this technology as a pilot program on the Hoen Avenue project. To further improve the situation, city staff developed an alternative roadway alignment and pavement section, which shifted the travel lanes away from the outer creek bank edge to reduce impacts caused by soil settlement.
To maximize the soil stability, a lightweight polyurethane material was injected into the soil to fill voids at depths up to 24-feet. When the material cured, the soil became more stable in a matter of minutes. This process is important as it allows for minimal roadway closures and eliminates the need to excavate. For a period of a year following the polymer injection, city survey crews continued to monitor the established control points for movement; the data showed the embankment had stabilized. City street crews were then able to begin working on pavement rehabilitation which was completed on March 16.
In applying the deep polymer injection technology, shifting the travel lanes away from the creek, and implementing permanent parking restrictions, Hoen Avenue was able to reopen to 2-way traffic at a cost of $225,000.
View more city infrastructure projects https://srcity.org/690/Capital-Improvement-Program