Technical Information

Mud pressure balanced type / earth pressure balanced type MPB type / EPB type Mud max method

MPB type / EPB type pipe jacking method

MPB type / EPB type pipe jacking method

In the EPB type pipe jacking method, the cutter chamber of the EPB type TBM whose front part is sealed with a bulkhead is filled with excavated soil or excavated earth and sand mixed with additives (mud soil), then, the pressure of the earth and sand is maintained at a commensurate pressure with the earth pressure of the face and the groundwater pressure to stabilize the face.

In addition, it is a construction method in which the jacking pipe is pushed and installed by the thrust force of the main hydraulic jack installed in the driving shaft while adjusting the amount of excavated earth and sand discharged with a screw conveyor.
Excavated soil is discharged by the muck backet, squeeze pump, or vacuum device.

The EPB type pipe jacking method is classified into the earth pressure type and the mud pressure type depending on the presence or absence of additive injection.

In addition, additive injection is generally performed to promote plastic fluidization of excavated soil when the content of silt and clay is less than 30%.

Characteristics of MPB type / EPB type Mud max method

  • Characteristic 1It can be applied from cohesive soil to boulder layers and hard soil.
  • Characteristic 2It is systematized from excavation to soil removal and solidification processing, and continuous work is possible.
  • Characteristic 3It requires less ground equipment and can be installed in a narrow yard.
  • Characteristic 4By disassembling the screw conveyor and carrying it in, it can be loaded from a small shaft.
  • Characteristic 5The TBM length is short, and sharp curves can be constructed by using a copy cutter (φ2000 mm or more).
  • Characteristic 6By using TBM type for reaching manhole, 100% of equipment can be retrieved.
  • Characteristic 7The vacuum device can be used for pipe diameters of φ1000 mm or more.
  • Characteristic 8Long-distance pipe jacking is possible with the auxiliary system.