Auger Boring (Jack and Bore)
Auger boring (jack and bore) is commonly used for installing gravity sewer lines, water mains and utility conduits in urban areas with dense infrastructure, where traditional open-cut excavation is impractical.
How It Works
Auger boring is a cost‑effective, minimally invasive trenchless solution for installing steel-cased utilities beneath obstacles. With casing sizes up to 84″ and drives extending several hundred feet, enhanced by modern guidance and cutter technologies, it is a reliable go-to for under‑crossings with tight surface and accuracy constraints.
Benefits
- High surface preservation – minimal disruption to roads, railways, landscapes, and structures.
- Reliable and proven – straightforward process with strong track record and low operational cost.
- Versatile – works in soils, clays, even rock using cutter heads or Small Boring Units.
- Accurate – modern pilot tube guidance systems effectively control line and grade.
- Safe and efficient – auger boring is non‑explosive and well-suited for crossings in busy urban or environmentally sensitive sites.
Application & Technical DEtails
- Typical uses: ideal for under‑crossings of highways, railroads, airport runways, storm sewer, water, gas, electrical, fiber, and communications lines.
- Casing diameters: commonly ranges from ~4″ to 84″, with typical steel casing sizes between 12″ and 72″.
- Drive lengths: standard bores are 100–500 ft; lengths up to ~400 ft are routine, especially using pilot‑tube guidance, and even longer with specialized setups.
- Pipe types: steel casings house carrier pipes (PVC, HDPE, ductile iron, steel), installed after casing is jacked into place.
- Equipment & extras:
- Small Boring Units (SBUs) attach to a lead casing for small drives (24–66″) and rock conditions.
- Pilot tube systems offer enhanced precision by pre-installing guided tubes on line and grade.
- Cutter heads (roller cone, disc) and slurry or water flush are used in rock and cohesive soils.
- Typical pit sizes: 40–60 ft long by ~14 ft wide, with thrust walls, torque plates, dewatering, and spoil handling measures.
- Tolerances: horizontal and vertical alignment within about ±3″; overcut typically ≤1″ annular space.
