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Simultaneous Injection Pipe

Simultaneous Injection Pipe

1. The simultaneous injection method for backfill grout injection involves the installation of an injection pipe at the upper part of the shielding machine and then injecting backfill grout at the same time as the shield machine drills and creates the tail void.

Using simultaneous injection a mixing nozzle blends two liquids at the tip of the injection pipe. This allows injection to occur in the same way as segmental injection, therefore dramatically reducing problems caused by blockages.

Simultaneous Injection Pipe: Tip Mixing Type

Type MP-8(Low Protrusion 2-liquid only type)3.5gen MP-91(Low Protrusion 2-liquid only type)4gen
Mixing Method Injection Type B Liquid Nozzle
Injection Type B Liquid Nozzle
Maintenance Method B Liquid Attachment Detachment + Cleaning Stick AB Liquid Attachment Detachment
Body Height (Protruding Height) 55mm(75mm)
A Liquid Pipe Inner Diameter 32mm(0.64)
A Liquid Recommended Flow rated Flow rate 20~100L/min(0.4~2m/s)

Simultaneous Injection System

Simultaneous Injection Pressure Measurement

Injector Maintenance

The simultaneous injection pipe indicator for needing maintenance is the increase of back pressure in B liquid pressure as well as back pressure in the washing water pressure. It is necessary to regularly replace tube rubber. In addition, as mortar “cholesterol” can sometimes adhere to the inner surface of the injection tube, it is best to circulate in the tube with TAC clean or to clean it with a can tool.


TAC Corporation