Case Studies

US-401 & Ligon Mill Rd Improvements

Project Details

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Project Name
US-401 & Ligon Mill Rd Improvements
General Contractor
Moffat Pipe, Inc. - Wake Forest, NC
Location
Wake Forest, NC
Ground Conditions
Sandy clay with cobbles
Akkerman Equipment
5200 Pipe Jacking System with WM48S-D TBM. Mixed-Face Disc Cutterhead, VL-80 Laser Guidance System. 524 Haul Unit and accessories
Pipe
48-in OD steel casing (0.625-in wall thickness)
Total Length/Hard Rock Section
Twin drives totaling 880 LF (2 × 440 LF)

Project Overview

Moffat Pipe, Inc. completed tunnel boring operations for the US-401 and Ligon Mill Road Improvements project in Wake Forest, North Carolina. The project required installation of a 48-in steel casing beneath roadway infrastructure while maintaining precise line and grade control in variable ground conditions.

Originally planned as a jack-and-bore operation, the contractor deployed an Akkerman 5200 Pipe Jacking System with TBM capabilities to improve efficiency and maintain alignment across extended drives. This approach allowed the crew to complete the crossing with minimal surface disruption while adapting to mixed ground conditions.

Challenges

  • Variable subsurface conditions including sandy clay and cobbles
  • Maintaining alignment accuracy over twin long drives
  • Need to optimize installation method for efficiency and access constraints
  • Managing excavation performance in mixed-face ground conditions

Solution

  • Utilized the Akkerman 5200 Pipe Jacking System with WM48S-D TBM to maintain precise line and grade control
  • Deployed a mixed-face disc cutterhead to effectively excavate cobbles and cohesive soils
  • Incorporated laser guidance systems to ensure alignment accuracy over extended drives
  • Leveraged pipe jacking methods to reduce surface disruption and improve installation efficiency

Outcome

  • Successfully completed two 440 LF tunnel drives totaling 880 LF
  • Maintained accurate line and grade control through mixed ground conditions
  • Achieved efficient excavation and consistent production using TBM technology
  • Minimized surface impact along the roadway corridor
  • Demonstrated the flexibility of pipe jacking and TBM systems for complex utility crossings

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