jet grouting pile construction

The process flow of jet grouting pile construction mainly includes the following steps:

Preparation before construction: remove obstacles on the ground and underground, remove miscellaneous fill soil, silt, etc., remove accumulated water, and use well-graded mud and gravel to backfill in layers. Lay out the lines and locate the piles after clearing the obstacles. Use steel bars or wooden piles as markers and number them, and then move the machine to its position.

Positioning and adjustment of drilling rig: Move the drilling rig and align it with the hole position. The deviation between the drilling position and the designed position shall not exceed 50mm. At the same time, level the drilling rig to ensure that the verticality deviation of the main shaft of the drilling rig is not more than 1.5%.

Drilling and inserting pipes: The axis of the drill rod and the center of the pile hole are on the same plumb line to ensure the verticality of the drilling hole. When drilling, attention must be paid to the verticality of the hole, and core tube drilling should be adopted when necessary. If an old foundation is encountered, a diamond drill bit can be used to drill to the predetermined depth of the final hole. During the insertion process, in order to prevent mud and sand from clogging the nozzle, the high-pressure nozzle sprays water while inserting the pipe.

Preparation and spraying of cement slurry: Before construction, the construction company's slurry preparation personnel check whether the grouting system is operating normally and whether the slurry delivery pipe is unobstructed. Determine the construction parameters such as the slurry delivery volume of the slurry pump and the lifting speed of the equipment. When the pile driver drills to the designed depth, you can start mixing cement slurry according to the designed mix ratio. The slurry must be mixed strictly according to the predetermined mix ratio. During construction, it is advisable to use a flow pump to control the slurry delivery speed. The outlet pressure of the grouting pump should be maintained at 20-25MPa, and the mixing and lifting speed should be synchronized with the output speed.

Spray grouting: When spraying, the predetermined spraying pressure and spraying volume should be reached first, and then the grouting pipe should be gradually lifted. In the event of a fault in the middle, the lifting and rotary spraying should be stopped to prevent the pile body from being interrupted, and the fault should be checked and eliminated immediately.

After the spraying construction is completed, the grouting pipe and other machinery and equipment should be rinsed with clean water to prevent solidification and blockage. Then move the machinery to the next pile position and repeat the above construction process.