Auger Boring - Raleigh Boring

Horizontal Auger Boring is a term used in the trenchless underground construction industry that has several similar names and applications: Road Auger Boring, Horizontal Earth Boring, Guided Auger Boring, Jack and Bore, Pipe Jacking, Pipe Ramming, Sliplining and Concrete Box Jacking.

In general auger boring is more precise that directional drilling and its used to place pipes on precise grade and under surfaces that can’t be disturbed like roads and railroads.

Auger Boring:

A technique for forming a bore hole from a drive pit to a reception pit, by means of a rotating cutting head. Spoil is removed back to the drive shaft by helically wound auger flights rotating in a steel casing. The auger boring equipment may have limited steering capability.

Raleigh Boring Directional Bore | Boring Pilot Hole

Pilot Bore:

A pilot (bore) hole is a small hole drilled as a guide for the drilling of a larger hole.

The action of creating the first (usually steerable) pass of any directional boring process, which later requires back reaming or similar bore hole enlargement.

The process begins when a directional bore machine pushes a bore head connected to hollow pipe into the ground at an angle. As each joint of drill pipe is pushed into the ground a new joint of pipe is added behind and torqued until it reaches its predefined destination and exit point.

Raleigh Boring Directional Bores | Pipe Reaming

Back-Reaming:

Upon reaching the destination exit point, the drill bit is detached and the end of the drill pipe is attached to a reamer or hole opener (for rock) if the borehole must be enlarged. The reamer is pulled back while rotating the drill pipe with as many consecutive passes as needed to enlarge the hole. Drill pipe is added behind the reamer or hole opener so that there is always drill pipe in the borehole.

Raleigh Boring Directional Boring | Pipe Pull-Back

Pull Back:

Pull-back is the part of the horizontal directional drilling process in which the drill string is withdrawn through the bore back to the entry pit, usually installing the product pipe at the same time.

The success of a horizontal directional drilling (HDD) drill is largely dependent on the success of the pull back operation, when the product pipe is installed in the created borehole. The cost of damaging pipeline and the costs for additional measures during and after the pull back operation can be considerable if not managed properly.

Some of the problems which might occur during a pull back operation vary from uncompleted pull back operations to slight coating damages.

When the bore hole is approximately 25% larger than the product pipe to be installed, the end of the product pipe is connected to a reamer or barrel reamer and then a swivel attached to the pipe to be installed and pullback commences.