On May 15, 2013, Huayuan Overcame the Challenge of 3D HDD and Successfully Completed the Fushun Gongjiagou Crossing

On May 15, 2013, Huayuan Overcame the Challenge of 3D HDD and Successfully Completed the Fushun Gongjiagou Crossing

On May 15, 2013, the Fushun Gongjiagou Horizontal Directional Drilling (HDD) crossing project was successfully completed, marking Huayuan’s breakthrough in overcoming the challenges of multi-vertical and horizontal curve crossings in high-hardness strata — another significant step forward in the company’s HDD capabilities.

Located in Shuncheng District, Fushun City, Liaoning Province, the project had a total crossing curve length of 1,240.3 m, with an entry angle of 10°, exit angle of 9°, a total horizontal curve deflection of 43.4°, a crossing depth of 21 m, and a radius of curvature of 550 m. The pipeline consisted of D219 × 8.0 mm seamless steel pipe covered with 53 mm rigid polyurethane foam insulation jacket.

The site conditions were particularly challenging:

* To the south, the curved Shenyang–Jilin Expressway; to the north, the foundation of a flooring factory in Gongjiagou Village. A conventional HDD curve could not avoid both the highway embankment and the building foundations at the same time.

* The main stratum consisted of moderately weathered granite with high rock hardness, making 8 conventional reaming operations difficult to complete in a short time.

* The foam insulation jacket had low strength and was easily scratched or detached from the steel pipe, demanding extremely smooth borehole walls and a precise pilot hole.

To overcome these constraints, Huayuan broke away from the conventional design of having only vertical curves, or vertical curves with a single horizontal curve, and creatively designed a 3D crossing curve with five bends in space.

With as many as five bends and a total deflection of 43.4°, the pilot hole drilling was highly prone to deviation from the design curve. To address this, Huayuan applied its self-developed DX-I guidance system together with its latest magnetic target tracking and measurement tool, ensuring the pilot hole was drilled precisely along the designed path in a single pass, meeting all project specifications.