About horizontal auger drilling

Horizontal auger boring method is a cost-effective and versatile technique for installing steel casing or product pipes under rail tracks, roads and highways or inner-city. 

Short Introduction

Auger boring machines typically are placed in a pit on gr ade with the bore profile and exits into an exit pit.

At the pit launched horizontal auger boring method, pipes are pushed through the soil concurrently with soil cutting and soil removal helical by an rotating auger into the launch pit.

An Advantage of ABS drilling systems is the possibility to guide the bore (also known as PTMT), a method applied for the installation of pipes which require high accuracy in line and grade. For this horizontal drilling method a special measuring technology we developed especially to use with the BPU line of drilling systems.

The ABS drilling units needs no other auger drilling system to push the pipes after guiding the pilot like some other combined systems,  the jacking force of ABS drills is high enough to finish the jobs alone.

Further we developed a special steerable cutter head to install product pipes directly with an ABS boring unit (as a microtunneling method).

Unguided Auger Boring

The method of forming a bore, usually from a pit, using a rotating cutting head is called the Auger boring method. Soil is removed back to the start pit by helically wound auger flights rotating in a steel casing. The equipment may have no steering capability.

Guided Auger Boring

At this kind of auger drilling, a guided pilot hole is bored with an asymmetric faced cutting head (called steering head) and the aid of a theodolite and CCD camera on the displacement principle. The pipe is then driven after connecting the pilot rods to the bore head (via a pressure bearing or widening stage for the pilot bore axis). Accuracies of +/- 2 cm are achieved, irrespective of the length of borehole.

PTMT is a multiple-step-process

First Step: Pilot Bore  

At given slope a pilot drill string are drilled into the ground at a displacement method.

The drill string (direction and slope) are controlled by a camera. The guidance are possible with theodolite, target at pilot head and optical alley inside the drill pipes.

accuracy +/– 2,00 cm from center line.

Second step:  Enlargement with the special ABS hollow-stem auger system

With the hollow-stem auger control developed by ABS, the guided pilot drill string is also pushed into the ground. However, to enlarge the hole and to install the pipes, the bore head is not forcibly connected to the pilot rods but guided along the pilot tube. This means that the bore head, auger and driven pipe overbore the pilot string. The pressure bearing and widening stages can thus be omitted. No thrust is required to push the pilot into the end pit for recovery. This process can be used for guided blind bore holes.

During microtunneling with diameters exceeding DN 400, problems may arise with the pressure bearing or widening stage. This can be due to excessive thrust on the pilot rods, constraining forces or uneven ground during driving.