Application of XL-50 Jet Grouting Drilling Rig in Reservoir Dam Reinforcement

Application of XL-50 Rotary Jet Drilling Rig in Reservoir Dam Reinforcement

The basic principle of a high-pressure rotary jet impermeable wall is as follows:

Using a drilling rig to make holes, the grouting hard pipe (i.e. drill pipe) and its nozzle are placed at a predetermined stratigraphic depth, and the prefabricated cement slurry is pressurized by a high-pressure pump and delivered to the nozzle through a high-pressure hose, which is ejected from the nozzle, impacting and cutting the soil, and filling and mixing it with a forced mixing of cement slurry, while lifting the drill pipe at a certain speed to form a new, artificial foundation or underground impermeable structure. When these individual structures are joined and glued together, they form a continuous underground impermeable wall. Compared with the traditional mobile drilling rig, the XL-150 crawler-type rotary drilling rig is more advanced, with all the machinery controlled electronically, more convenient and user-friendly operation, and higher vertical accuracy.

Features of the new jet grouting drilling rig:

The new rotary drilling rig xL-50 has the following features:

• crawler chassis loading, compact structure, and centralized operation. It is convenient for walking, moving, and positioning.
• fully hydraulic power head drive, step-less variable speed, low labor intensity.
• equipped with display devices for drilling tower vertical, power head rotation and lifting speed, high drilling efficiency, good verticality, and real-time control.
• the drill tower is equipped with a vertical, rotary head, and lifting speed display devices, with high drilling efficiency, good verticality, and real-time control.
• the diameter of the drill pipe is 450mm, the drilling depth can reach 50m, and the variable speed range of the power head is wide, which can meet the construction requirements of various rotary spraying projects with single, double, and triple pipe tools.

The main construction methods are as follows:

①Drill in position: Place the crawler drilling rig in position according to the designed hole position, start the movable arm to adjust the verticality, and start drilling.

② Preparation for injection: After drilling to the design depth, start mixing the slurry and adjusting the pressure of the high-pressure variable frequency pump as required.

③Jetting grouting: Firstly, start the drilling rig to rotate the grouting pipe. And start the high-pressure mud pump to send water into the hole. After the pump pressure is normal, move the slurry pump's suction pipe to the slurry storage barrel and start the slurry injection.

④ Lift the pipe: After starting grouting until the estimated fore peak of cement slurry has flowed out of the nozzle, start lifting the grouting pipe according to the selected parameters and injecting grout from the bottom up.

⑤Stop the pump: When the injection grouting reaches the design depth and the cement slurry returns from the orifice, the grouting can be stopped. Move the suction pipe of the grouting pump to the clear water tank, and pump out the cement slurry in the grouting line to stop the pump.

⑥Cleaning apparatus: The unloaded grouting pipe should be immediately flushed with clean water to clean each channel and screw on the plug. The grout pump, slurry feeding line, and mixer should be cleaned with water.