How to Set the Jacking Frame for MARS 450/400 TBM

Safety first

In the world of underground construction, precision is vital, but safety is mandatory. 

Setting the jacking frame correctly is the foundation of a successful microtunnelling drive.

If the frame is not aligned properly, the TBM will not enter the soil on the correct path, and deviation problems will occur.

1. Aligning the Center Point (CP)

The most critical step is matching the Jacking Frame Center Point with the Alignment Center Point provided by the project surveyor.

This point is also used to set the laser guidance system.

Pro Tip: Even a 1 mm error at the shaft can cause major deviation after 50 meters of tunneling.

2.  Leveling and Stability

After marking the center point, place the jacking frame on the shaft base.

Check the frame level in four directions:

Vertical level (Up–Down)

Horizontal level (Left–Right)

The frame must be perfectly level to ensure the TBM pushes straight.

3.  Securing for Heavy Loading

Microtunnelling involves extremely high hydraulic jacking forces.

To prevent frame movement:

Use strong angle bars on all sides

Weld or bolt supports to shaft walls

Ensure the frame is completely immobile during operation

Even small movement can affect machine steering and pipe alignment.

If you have any technical questions or face problems on site, leave a comment below. I will share practical solutions based on field experience.