Large-Dimension Bored Piles for the Extension of Munich’s U5 Underground Line
The extension of the U5 underground line from Laimer Platz to Pasing is an important infrastructure project for Munich, Germany. The large dimensions of the pile foundations for three new railway stations, starting shafts and sealing blocks make the construction very challenging. The internationally operating construction company Max Bögl, headquartered in Germany, is using the Liebherr LB 55 large-diameter rotary drilling rig with the Kelly drilling method to install a total of 1400 cast-in-place secant piles with a diameter of up to 1500 mm and a depth of down to 50 m. With 550 kN·m, the rotary drive delivers the necessary torque for the application.
The LB 55 was specially designed for large-dimensioned bored piles, such as those required for the extension of the U5 underground railway line. “We decided in favour of the LB 55 due to its outstanding performance. It is flexible and can be assembled and disassembled quickly. It makes our daily work on the jobsite much easier, especially when installing bored piles with large dimensions,” says Robert Geitner from the deep foundation fleet department at Max Bögl.
Greater Depths With Kelly Drilling
With the LB 55, Liebherr has significantly improved the performance data compared to the predecessor model LB 44. With an optional larger drilling axis, the new model can create piles with a diameter of 3000 mm for cased applications and 4800 mm for uncased boreholes. With Kelly drilling, drilling depths of up to 120 m are now possible – an increase of 25 m. The largest drilling rig in the LB series is powered by an engine output of 565 kW, which is an increase of 70 kW compared to the previous model. With these performance data, the LB 55 is a suitable choice for applications with large drilling dimensions.
The LB 55 is designed for a wide range of applications using various drilling methods – Kelly, continuous flight auger drilling, drilling with full displacement tools or double rotary drilling – and it has a compact transport weight as well as modern assistance systems to increase efficiency.
