Emergency Sinkhole Repair in Natchez, Mississippi

Problem

The Mississippi Department of Transportation (MDOT) contacted URETEK for an emergency repair when a large sinkhole formed on highway 61 in Natchez, Mississippi, and effectively shut down a major portion of the roadway. The situation required urgent attention because the sinkhole obstructed the route to a nearby hospital.

Analysis

Upon inspection of the sinkhole, URETEK and MDOT determined that a misaligned 24-inch reinforced concrete pipe (RCP) caused the damage. A leaky joint in the RCP degraded the support soils and caused voids beneath the pipe to form.

Solution

A URETEK crew mobilized quickly for an emergency repair. First, they mechanically aligned the pipe with a trackhoe, and then they used the URETEK Deep Injection® (UDI) method to stabilize and seal the pipe. Finally, URETEK filled the excavated area with #57 stone aggregate and stabilized the aggregate at every four to five feet of fill to create a solid, monolithic mass below the highway.

Result

URETEK successfully completed this emergency project in just two work days. URETEK solved MDOT’s immediate problem by sealing and rehabilitating the stormwater drainage system, but also prevented the formation of future roadblocks by stabilizing the highway’s underlying support soils.

URETEK Deep Injection® (UDI)

Widely referenced throughout our industry, UDI involves the injection of structural polymer into base and subgrade soils to increase the load bearing capacity. This is achieved by injecting the polymer through small holes drilled directly through the pavement structure to depths determined by site-specific analysis. Our URETEK 486 Star® material flows easily into voids and weak zones within the soil mass below. Through a controlled chemical reaction, the expanding polymer compacts surrounding soils and applies a controlled pressure on targeted areas of the affected pavement above. If needed, a multi-injection design plan is utilized to gently return the pavement to its original grade. The composite material quickly cures into a strong, dimensionally stable, and water-resistant geo-material, providing years of reliable service.

URETEK 486 Star®

URETEK 486 Star® polymer is a two-component, high-density, expanding thermoset polyurethane system. It was developed to be the ideal solution for under-sealing, void filling, lifting of settled pavement, stabilization and stiffening of weak soils, and for encapsulating and sealing buried infrastructure. URETEK 486 Star® is environmentally inert, non-toxic, and resists underground water erosion or weakening due to its industry-leading hydrophobic properties.

URETEK used a trackhoe to mechanically re-align the leaky RCP
URETEK used UDI to bind the aggregate fill material