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Horizontal directional drilling Full face technology Open shield technology Rehabilitation Combined construction Cut-and-cover method
• Movie - Open shield technology

Project in Dresden, Germany

• Open shield technology

Open shield tunneling machine
Open shield tunneling machine

The development of open shield technology is based on mining techniques under the cover of manually controlled hood shields.


Braumann supplies controllable open shield tunneling machines starting at a nominal diameter of DN 1200 and reaching up to DN 3000. They are equipped  with an excavator arm (draw hooks) for gravel soil and milling heads for solid rock.


Open shield technology has been successfully applied by Braumann since 1985. All tunneling machines are developed, built  and serviced at the company´s own technical service centre in Antiesenhofen, Austria.

• Advantages of open shield technology

  • Due to the open and visible working face the soil can be mined and documented easily
  • Unexpected obstacles are recognized immediately and can be removed without special recovery
  • High efficiency mining especially  in dry and soft soil
  • Application in solid rock with drilling heads is possible
  • Walkability ensures fast and easy repair- and service-activities
  • Long segments can be constructed and connected under ground
  • Pinpoint accuracy due to state of the art surveying- and control-technology
• The procedure of open shield technology

Cutting head
Cutting head

When it comes to mining soft soil, draw hooks gained the most acceptance.


The excatator arm can be adapted with ripper teeth or a hydraulic hammer can be installed.


To put it brief and simple, open shield technology proceeds in three typical steps:

Loosening - Loading - Hoisting

Excavator arm at the working face
Excavator arm at the working face

1 Lösen


The soil is loosened at the working face by a telescope excavator arm or a cutting head, protected under a hood shield, and then pulled onto the installed conveyor-belt.

Loading excavated soil via conveyor-belt
Loading excavated soil via conveyor-belt

2 Loading


The conveyor-belt transports the excavated soil to the stand-by-conveyor-bucket

Conveyor-bucket is hoisted above ground
Conveyor-bucket is hoisted above ground

3 Hoisting


The full conveyor-bucket is pulled into the starting pit by hydraulic winches and steel ropes, hoisted to the surface and taken to the deposit.

• Special solutions

As jacking specialist Braumann has developed various technical options:

Hoisting the inside of a jacking machine
Hoisting the inside of a jacking machine
  • Production of open shield jacking machines and their connection to given facilities under ground
  • Production of open shield jacking machines without target pit, thus with a machine pipe that stays under ground while all other technical devices are dismantled
  • Jacking through known obstacles
  • Jacking in contaminated grounds (via full face technology)
  • Jacking in grounds containing suspected war relicts with the assistance of a pyrotechnical specialist watching the working face