Highway HDD Crossing
Four-way conduit placed under the highway without a single lane closure.
What the job required.
64 m bore of four-way HDPE conduit beneath a two-lane provincial highway, plus tie-in pits and restoration.
The challenge.
The municipality required a four-way conduit crossing beneath a major two-lane provincial highway, explicitly prohibiting any surface cuts or lane closures. The right-of-way contained a high-pressure gas line and a major fiber trunk, drastically reducing the permissible alignment window.
Engineering specifications mandated a strict minimum cover requirement over the length of the bore to ensure highway structural integrity. Navigating this narrow corridor without breaching surface tolerances or existing utility offsets required precision tracking and control.
Our approach.
Before the drill rig was mobilised, ASI hydrovac crews verified and daylighted all located utilities along the crossing path. The proposed bore profile was plotted against these known utility depths and the minimum cover requirements, with final approval secured from the infrastructure owner.
The bore head was continuously tracked for pitch, roll, and depth across the entire length of the pull. Drilling fluid was mixed, contained, and recycled on-site, preventing environmental contamination and ensuring stable downhole pressures throughout the installation.
The result.
The 64-meter road crossing was executed flawlessly, with the four-way HDPE conduit bundle placed beneath the highway without a single lane closure. The highway surface remained completely untouched, with civil restoration cleanly limited to the entry and exit pits on either shoulder.
A comprehensive bore log and an as-built depth profile were issued at handover, proving compliance with the minimum cover specifications. The conduit was mandrel-proofed and roped, delivering a ready-to-use pathway for the utility owner.
