Jun 13, 2019

Spotlight on Hydraulic Solutions for Tunnel Boring Applications

Hydraulic Applications

You can find hydraulic motors powering a number of different functions in tunnel boring machines including:

  • the cutting drive that rotates the cutting shield
  • the screw conveyor that extracts the soil from the machine
  • the erector rotation drive that positions the tunnel lining segments

Beyond these applications, Hydraulic pumps are a viable solution for the thrust cylinders, which power the machine forward.


Electric or Hydraulic?

In smaller diameter tunnel boring machines (5 meter and smaller) the diameter constraints and architecture of the tunnel boring machines make hydraulic motors the most viable solution for these applications as opposed to electric motors which require a larger diameter, length and weight to place the amount of motors to meet the same torque output.

Poclain Hydraulics MS series or MI series motors meet the high displacement and torque output requirements for cutting drives, screw conveyors, and erector rotation drives, while our PL pump line has seen success in thrust cylinder applications.

Tunnel Boring Success in China

With more than several hundred motors supplied each year for tunnel boring machines across the world, Poclain Hydraulics is a leader in this industry.

TIANHE, a Chinese state-owned company, is one of the leaders in China for manufacturing of tunnel boring machines producing more than 80 machines per year in its factory, located in Changshu (North- West of Shanghai).

M. Zhang Tianju, Deputy Director for R&D, shared that the decision to select Poclain Hydraulics motors for the cutting drive, the auger drive and the erector rotation was justified by Poclain Hydraulics’ strong experience in this market as well as references, especially in Japan.

Based on the machine size (mostly between 2, 7 and 15 meters) and required torque, the design teams selected the MS35 (up to 4,200cc displacement, pressure up to 450bar) and the MS50 (up to 6,000cc and 450bar) motors for these functions.

In order to provide sufficient torque, each function is driven by several motors.


Beyond torque output, The MS motor’s modularity and possibility to adapt a parking brake to hold the motor shaft in position for the erector rotation drive, was another reason for this choice.

M. Zhang Tianju also emphasized the extreme reliability offered by Poclain Hydraulics’ components. These motors can run flawlessly for more than ten years, giving Tianhe the opportunity to re-use them when building new tunnel boring machines and helping accelerate the return on investment for end users.

Learn more about our solutions for tunnel boring machines