The Nitty Gritty

The official Team UMA Blog

Hatteras Ferry Terminal Soil Stabilization: Noninvasive HDPR Solution

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Hatteras, North Carolina is home to the iconic Cape Hatteras Lighthouse and over 50 miles of beautiful shoreline.  While the year-round population is about 3,000-4,000, this spikes in the summer months to 50,000+ visitors per week.  The Coast Guard Station Hatteras Inlet is also located on the southern end of the island, and is a multi-session unit- meaning search and rescue, boating safety, and law enforcement, and marine environmental protection operations are all performed.  The nearby ferry terminal for this wonderful island is both necessary, and enjoyable- and recently, was in need of repair.

When the original seawall was put into place, the concrete piles were installed using water jetting.  Once the row of piles were in place, concrete panels were set and sealed in between the piles.  An issue with the seal between the precast panels and the piles at the ferry terminal was causing soil to pull through the wall, into the ocean.  Sinkholes were beginning to form behind the wall, next to the Coast Guard Station Hatteras Inlet.  The NCDOT reached out to URETEK MA for a environmentally friendly, non-invasive solution to prevent further loss of soil behind the seawall.

Stabilizing the soils using high-density polyurethane resin would allow the panels and piles to be sealed from the back side, and prevent future formation of sink holes.  The injection of hydro-insensitive resins would also fill any present voids, or sinkholes, and could be easily controlled in this environmentally sensitive area.  To begin, the joints of the panels were located with the help of divers, and tubes were driven down to depths of 20 feet.  These tubes facilitated URETEK’s patented Deep InjectionTM of HDPR.

While on site, beyond a water containment boom used to catch any excess HDPR, a diver was in the water both filming for live-feed of the Deep InjectionTM of HDPR, and covering any leaks with wire mesh.  By monitoring the process with both a live-stream of video, as well a diver, all leaks were able to be successfully repaired.  These important precautions insured the repair was non-disruptive to not only the residents of Hatteras, but to the environment.

The sinkholes forming behind the wall were successfully filled, and the soil was stabilized.  The newly sealed joints, insured a stable, and functioning ferry terminal- for residents, and vacationers alike.


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