The historic development of trenchless pipeline construction shows that diameters kept getting smaller while pipeline lengths were extended continuously.
To meet this demand the so called microtunneling-machines, today known as full face heading machines, were developed. Full face technology is applied for walkable cross-sections as well as non-walkable.
Design of a full face heading machine
Braumann has been raping the benefits of full face technology for many years. Every single component of the drilling gear is contiuously improved in the companies own technical service centre.
Based on the preliminary basic geological information the cutting wheel and the tooling are especially tuned to every individual project by the technical service centre.
During the entire jacking the site manager and technical service watches the jacking speed, the mining and the wear characteristics.
• Advantages of full face technology
Perfect performance in ground water without water pumping or compressed air support
Economical jacking in granular soil as well as in solid rock
Applicable for non-walkable nominal diameters from DN 300 on
Depending on techical capacity and nominal diameters pipeline lenghts of 1000 meters and more can be jacked
Vertical, horizontal and three-dimensional curves can be realized
Thanks to the advanced degreee of automation high shift performances can be reached over a long period of time
Pinpoint accuracy due to state of the art surveying- and controltechnology
• The procedure of full face technology
The surveying and controlling of all activities is conducted at the central operating station (1) in the starting pit.
Press cariage/shield cradle (2)
The jacking machine and all jacking pipes are lowererd to a so called "shield cradle" (2), adjusted in the starting pit. The horizontal jacking starts from there.
The rotation of the drill head (3) and the contact pressure of the press carriage add up to the mining process at the working face. In the breaking machine (location of headers, drilling block and ring-chamber) the soil is grinded and mixed with the drilling fluid.
Via delivery lines the mined material is lead to the separation plant (4) where solids are filtered out. The drilling liquid gets back to the breaking machine by feed pipe and keeps on circulating.
Operating station screenshot(5)
Surveying and controlling of the jacking are conducted at the operating station by visual and digital evaluation of the laser data. (5) Every single jacking parameter is digitally recorded and can be evaluated continuously.
• The target
Breakthrough in the target pit (1)
When the jacking machine has reached the target pit (1) all the components are hoisted to the surface. Then the pipe string can be jacked into the final position.
After the jacking is completed the technically required overcut is rendererd with insulation suspensions.
When it comes to very long drives the cylinders of all intermediate jacking stations have to be removed.
Finished pipe string(2)
After the closure of all lubricant holes, the removal of all on- and offgoing tubes, the final cleaning and the final measurement the pipe string can be handed over to the contractor.