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  • Gripper TBM

    Boring Dia. 8.1 m,
    YinSong Water Divison

  • Metro EPB Tel Aviv

    Boring Dia. 7.54

  • EPB & Rectangular

Slurry Tunnel Boring Machines

Slurry TBM provide face support by pressurizing slurry in excavation chamber to balance soil and water pressure on working face. The excavated muck is transported by a slurry circulation system. These machines are characterized by stabilizing working face in sandy to gravely ground with precise settlement control.

Precise pressure control There are two methods of ensuring that the face pressure is maintained with a slurry system. The first is by the use of differential pumping. I.e. the pumps used to supply and discharge the slurry from the machine are careful controlled so that the pressure between them is maintained at the face pressure. In these systems it is normal to use the variable speed of the discharge pump to control the desired flow, and the variable speed of the supply pump to determine the face pressure in the machine. The alternative method uses a pocket of air trapped in a chamber behind the bulkhead to apply a pressure to the slurry in the excavation chamber. This is the standard method CREG use in their design of slurry tunnel boring machines. This pressure control of the face can be maintained within tighter tolerances – normally ±0.1bar. Pressure regulation of gases is easier and more accurate than pressure regulation of fluids This system is independent of the slurry flow and allows a larger flow around the circuit without affecting the accuracy of face pressure control. An active face pressure can be maintained, controlled and adjusted even when the pumping system is switched off.

Wuhan, China

The TBM drive between Qintai Station and Wusheng Station (i.e. Lot 10 Phase 1 of Wuhan Metro Line 6) crosses Yangtze River with total length of 1732m where maximum water pressure is 4.5bar and minimum turning radius 350m. Main strata thereof are featured by clay, silty clay with powder sand, clay with gravel, weathered siltstone and moderately weathered limestone, etc. CREG TBM supplied for this project set an impressive record of daily advance of 28.5m.
Project Data
Project nameWuhan Metro
Total tunnel length1,73 km
Ground conditionsMudstone, sand, clay, silt, gravel
  • Max. daily advance rate: 34,5 m
  • Max. monthly advance rate: 394,5 m
TBM Data
TBM TypeSlurry
Boring diameter6,50 m (hydraulic)
Cutter head power630 kW
Max. torque6300 kNm
Total weight800 t
Max. working pressure6 bar

Thomson Line, Singapore

In Singapore Thomson MRT Line extends 30km in length. CREG designed and manufactured slurry TBMs for boring the TBM drive from Lentor Station to Mayflower Station. Major challenge faced is complex geology represented by full-face soft ground, mix ground, full-face rock, etc. CREG supplied tailor-designed TBMs with optimized cutter head layout, high-power drive and faster cutter head revolution as solution for the project.
Project Data
Project nameThomson Line T209
Total tunnel length1,366 km
Ground conditionsResidual soil, weathered granite
  • Because of complex ground conditions, the cutting wheel is designed and manufactured with high wear resistance
TBM Data
TBM TypeSlurry
Boring diameter6,67 m
Cutter head power1400 kW (electric)
Max. torque6326 kNm
Total weightApprox. 681 t
Max. working pressure5 bar