A Northern Virginia contractor was tasked with installing a 42-inch storm sewer line via boring. The project required a linear run of 24-ft, a width of 12-ft, and a depth of 22-ft in a clay mixture that the competent person classified as Type-C soil.
The project would be located next to two high traffic roads running 4-ft from the bore pit and 14-ft from the receiving pit. The contractor requested a temporary road closure permit that would alleviate some of the site challenges. VDOT had determined that closing either lane on each side would create a negative traffic impact in the surrounding areas. Additionally, the contractor would need to repair an existing sinkhole caused by an unforeseen pocket of gravel in between the hard clay mixture that gave way while boring. The project would require a protective system that could properly accommodate the launch and receiving pits while providing paramount soil support.
After carefully reviewing several protective systems, the contractor selected a slide rail system for both of the underground pits. A slide rail system is a modular protective system that offers flexibility for projects with undetermined underground obstacle placement, such as crossing utilities. The slide rail system allows for a quick installation with the use of a reasonably sized excavator. The contractor was very satisfied with the overall performance of the slide rail system, which provided a practical solution to the storm sewer installation.