What Should Be Noted When The Rotary Drilling Rig Is Driving Piles under The Lower Casing

The casing plays a crucial role in the pile driving operation of rotary drilling RIGS. It can fix the pile position, prevent the collapse of the hole opening, and isolate surface water. The quality of its lowering directly affects the hole-forming efficiency and the quality of the pile body. The following are the key precautions for the casing when driving piles.

1. Size adaptation: The diameter of the casing should be 20 to 40 centimeters larger than the designed pile diameter. In soft strata, the length of the casing should be further extended. This can effectively prevent the collapse of the peripheral soil layer and provide a stable working space for drilling.

2. Precise positioning: With the help of total stations and other equipment for positioning, the deviation between the center of the protective cylinder and the center of the pile position should not exceed 5 centimeters, and the top surface should be more than 30 centimeters above the ground. Precise positioning is the foundation for ensuring the straightness of the pile body's axis.

3. Verticality control: When lowering, use a level or plumb line for monitoring. The verticality deviation should be less than 1%. If it tilts, it will cause the borehole to be skewed, affecting the lowering of the steel cage and the force on the pile body.

4. Reasonable burial depth: In clayey soil, the burial depth of the casing should be no less than 1 meter; in sandy soil, it should be increased to 2-3 meters. In special strata, vibrating immersed tubes can be used for deepening. Sufficient burial depth can enhance the stability of the casing and prevent displacement or subsidence.

5. Firm sealing: The gap between the bottom of the casing and the soil layer should be compacted and sealed with clay. If necessary, cement slurry should be injected for reinforcement. A tight seal can prevent surface water from seeping into the hole and avoid it collapsing.

6. Recheck and inspect: After lowering, recheck the position, verticality and burial depth again. Only after confirming that there are no errors can drilling commence. Identifying problems in advance can reduce subsequent rework and ensure the continuous progress of construction.

The standardized operation of the casing when the rotary drilling rig is driving piles is the prerequisite for the quality of the completed piles. From size selection, precise positioning to sealing reinforcement, every step must be strictly controlled. Parameters should be flexibly adjusted according to geological conditions to fully leverage the protective function of the casing and lay a solid foundation for efficient and safe drilling operations.