In the fall of 2016, drilling contractor PPI Chrobok S.A. installed two new gas pipelines in Poland. The alignment, which runs along existing gas lines and through geologically challenging terrain, marked the first use of Herrenknecht’s Direct Pipe technology in Poland.
With the construction of a new north-south pipeline connection, Poland is reacting to the increasing local demand for gas. Part of this network expansion is the Czeszów-Wierzchowice Gas Pipeline Project in the southwest of the country. For some time, only horizontal directional drilling (HDD) has been used for crossing rivers or roads during pipeline projects in Poland. Used for decades, the method has proved its worth for large numbers of boreholes, but it reaches its technical and economic limits in heterogeneous, non-stable grounds.
The sandy, sticky clay of the pipeline crossings in Wierzchowice and Czeszów presented the drilling crew with just such project conditions. Furthermore, the two alignments with lengths of 2,300 and 1,522 feet, respectively, ran along existing gas lines. Uncontrolled deviations during the drilling process thus had to be avoided at all costs.
In view of these requirements, main contractor PGNiG Technologies S.A., together with drilling contractor PPI Chrobok S.A., opted for the innovative Direct Pipe technology from Herrenknecht. This method combines the advantages of microtunnelling and HDD technology. In a single step, the required borehole is created and the prefabricated pipe is simultaneously installed without a trench.
Thanks to the gyrocompass navigation system, which allows for an exact steering of the tunnel boring machine (TBM), the drilling crew precisely installed the two pipelines, with an outer diameter of 41.2 inches, underground in just 13 and 16 drilling days. In doing so, they safely crossed underneath several obstacles, including an ecologically sensitive fish pond.
The sticky ground that typically tends to cause blockages is not a barrier for the Direct Pipe method. Even at very high levels of friction resistance, the 500 tons of thrust provided by the Pipe Thruster in the launch shaft proved more than enough. Despite the small overcut of only a few centimeters, no damages were detected at the coating after the pipe laying.
Roland Kośka, planning and monitoring manager for the client, Gaz-Systems S.A., reported that “as a combination of HDD and microtunnelling, Direct Pipe overcomes the methods’ respective limitations which, to a large extent, are no longer obstacles to pipeline construction. This will also allow us to pursue new projects in the future and complete them economically, quickly and with minimal impact on the local infrastructure and environment.”
Herrenknecht is the only company worldwide to deliver tunnel boring machines for all geologies and in all diameters – ranging from 0.10 to 19 meters. The product range comprises tailor-made machines for traffic, supply and disposal tunnels, technologies for pipeline installation, as well as additional equipment and service packages.
- Direct Pipe (AVN800 + Pipe Thruster HK500PT)
- Excavation diameter: 1,140 mm
- Maximum torque: 90kNm
- Thrust force (Pipe Thruster): 500 tons
- Pipeline crossing lengths: 1,522 and 2,300 feet
- Product pipe outer diameter: 41.2 inches
- Product pipe material: steel pipe with 3 x LPP + GRP Coating
- Application: gas pipeline
- Geology: sand, cohesive clay, gravel
- Contractor: PPI Chrobok S.A.
- Main contractor: PGNiG Technologies S.A.
- Client: Gaz-System S.A.
FOR MORE INFORMATION:
Herrenknecht, (253) 241-3709, herrenknecht.com