Ammann SJL-120 Rotary Jet Drill Rig – MJS Method Construction in Jiaozuo, Henan
Location (Province): Henan
Location (City): Jiaozuo
Drill Model: SJL-120
Drill Tooling: 142 multi-hole drill pipe, 142 multi-hole drill bit
Process Type: Rotary jet grouting cut-off (water stop)
Construction Method: MJS Method
Stratum Conditions: 1-12m sandy soil layer, 12-56m sand layer
Construction Angle (°): 90
Hole Diameter (mm): 260
Hole Depth (m): 56
Pure Drill Tool Dismantling Time (min): 80
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Construction Method:
Equipment Configuration: One SJL-120 drill rig, one Juneng 230 high-pressure pump, one Juneng 90E high-pressure
pump, one 20 m³ air compressor.
1. Mark the position of each pile as required. First, use a pilot drill rig to drill a 260 mm diameter hole. Due to the thick
sand layer which is prone to collapse, bentonite must be used for wall protection during pilot drilling. Then insert a
200 mm diameter PVC pipe.
2. Move the pilot rig away and level the site to ensure a stable and reliable working surface for the drill rig. Align the
drill rig with the center of each pile as required and extend the outriggers.
3. Lift the drill bit with a crane into the power head, clamp it with the clamp, and seal the nozzles and suction ports with t
ransparent tape to prevent sand from blocking the nozzles. Then assemble the drill pipe sections one by one. When
connecting each section, ensure the sealing rings at each joint are not damaged to prevent leakage. Finally, install the
swivel.
4. Start the air compressor and high-pressure pumps from the backup system. Grouting pressure: 40 MPa, air pressure:
1.1 MPa, rotation speed: 10 r/min, lifting speed: 25 mm/min, return slurry pressure: 15 MPa. During construction, the rig
operator must constantly monitor changes in rotation pressure. Under normal conditions, the rotation pressure should
not exceed 4 MPa. If it exceeds this value, check the cause. Also observe the slurry return at the suction port. If there is
no slurry return, address the issue promptly. After grouting is completed, clean the drill pipe immediately to prevent
nozzle blockage.
5. Move the rig to the next hole position.
