Pipeline River Crossing Methods: HDD, Microtunneling, Direct Pipe® & Pipe Jacking

Installing a pipeline under a river, lake, or estuary requires a trenchless crossing method. Open-cut trenching is rarely viable for waterway crossings due to environmental permits, bank stability, and navigational constraints. Trenchless methods — HDD, microtunneling, pipe jacking, and Direct Pipe® — each offer distinct advantages depending on the project conditions.

Method 1 — Horizontal Directional Drilling (HDD)

HDD is the most widely used method for pipeline river crossings. A drill rig on one bank steers a drill string on a curved path beneath the waterway to an exit point on the opposite bank. Once the pilot bore is complete, the pipe is pulled back through the bore.

Advantages:

•       Fast completion for crossings under 5,000 feet

•       Single mobilization point possible

•       Suitable for a wide range of soil conditions

•       Widely available contractor base across North America

Limitations:

•       Maximum practical pipe diameter typically limited to 48–56 inches

•       Pipe must be pre-fabricated in a continuous string

•       Pullback force requirements increase significantly above 36-inch diameter

When HDD Needs a Pipe Feeder:

On large-diameter HDD crossings (36 inches and above), a pipe feeder is often used to assist the pullback operation. The UNI-PF250 can apply up to 200 short tons of continuous thrust behind the pipe string, reducing the tension load on the drill rig and preventing pullback failures on long or large-diameter bores.

Method 2 — Microtunneling

Microtunneling is a remotely operated pipe-jacking method in which a Microtunnel Boring Machine (MTBM) is launched from a drive shaft and steered to a reception shaft. As the MTBM advances, jacking pipes are pushed from the drive shaft by a pipe jacking frame.

Advantages:

•       High accuracy — suitable for gravity pipelines requiring precise grade control

•       Suitable for rock and hard ground conditions

•       No open excavation beneath the crossing

When a Pipe Feeder Supports Microtunneling:

In longer microtunneling drives, the pipe jacking forces required increase with distance. An auxiliary pipe feeder like the UNI-PF250 can supplement the main jacking frame — maintaining continuous forward movement and reducing the risk of the pipe string becoming stuck.

Method 3 — Direct Pipe® Tunneling

Direct Pipe® is a one-step installation method combining a TBM and a pipe feeder working simultaneously. The TBM excavates the bore face while the pipe feeder pushes the prefabricated steel pipeline forward from the launch pit in a single continuous operation.

Advantages:

•       One-step operation — bore and install simultaneously

•       No separate pullback phase required

•       Continuous bore support — pipe is in the ground as TBM advances

•       Smaller site footprint — no long stringing pad required

•       Effective in heterogeneous or permeable soils

The Role of the Pipe Feeder in Direct Pipe®:

The UNI-PF250 is engineered for Direct Pipe® operations — delivering 200 short tons of continuous axial force that matches the pace of TBM excavation without stopping, without pressure spikes, and without resetting.

Method 4 — Pipe Jacking

Pipe jacking uses a jacking frame in a drive shaft to push steel casing pipe forward as soil is excavated from the front. For the diameter range served by the UNI-PF250 (20–56 inches), pipe jacking operations benefit directly from a supplementary pipe feeder at the drive shaft.

Selecting the Right Method for Your River Crossing

Pipe Diameter under 24 inches:

HDD is typically the most efficient choice. Microtunneling is viable for grade-sensitive applications.

Pipe Diameter 24–48 inches:

HDD remains viable with pipe feeder support. Direct Pipe® and microtunneling are strong alternatives for longer drives or hard ground.

Pipe Diameter 48–56 inches:

HDD becomes challenging. Direct Pipe® tunneling or assisted pipe jacking with a 200-short-ton pipe feeder like the UNI-PF250 becomes the primary method.

Equipment Support for River Crossing Projects

Universal HDD provides the UNI-PF250 pipe feeder for HDD pullback assistance, microtunneling support, pipe jacking, and Direct Pipe® tunneling. The system's modular, crane-free design allows positioning at the drive shaft or pullback side without heavy lift equipment. Contact Universal HDD at unihdd.com or call (847) 857-7009