Analysis of the Complete Working Process and Operation Principle of Hole Drilling by Rotary Drilling Rig

Equipment positioning and leveling, laying the foundation for hole formation

Before the formal operation of the rotary drilling rig, precise positioning and body leveling operations need to be completed, which is the core prerequisite for ensuring the verticality and aperture accuracy of pile foundation drilling. The construction personnel calibrate the hole positions based on the pile foundation construction drawings, operate the drilling rig to the designated construction site, and adjust the position of the machine body to make the center of the drilling tool completely coincide with the center of the pile position. Subsequently, the leveling is completed through the hydraulic support legs of the machine body, and the flatness of the machine body is corrected by the equipment level detection system to prevent problems such as tilting and deviation of the machine body. A stable and horizontal body state can effectively avoid construction defects such as hole inclination, deviation, and collapse during subsequent drilling, laying a solid equipment foundation for continuous drilling and standardized hole formation, and adapting to various civil engineering and infrastructure pile foundation construction scenarios.

Pressure rotary drilling, soil layer fragmentation for soil extraction

After the positioning and debugging are completed, the drilling rig enters the core drilling operation stage, relying on the power head to provide rotational torque, driving the drill rod and the bottom drilling bucket to rotate at a constant speed. The equipment applies vertical downward pressure to the drilling bucket through its own weight and hydraulic pressurization system, allowing the bucket teeth to tightly adhere to the soil, sand, or soft rock formations, continuously cutting and crushing the rock and soil mass. As the drilling tool continuously rotates and presses down, the broken rock and soil debris will be automatically stored inside the sealed drilling bucket. After reaching the rated depth in a single drilling, the drill rod should be kept rotating at a low speed to avoid the collapse of the soil on the hole wall. This homework mode relies on the synergistic effect of mechanical pressure and rotary cutting, and is suitable for various complex geological conditions such as clay, sand, and gravel layers. It has high drilling efficiency and minimal disturbance to the hole wall.

Lifting bucket for soil unloading and resetting, continuous operation in a cyclic manner

When the rock and soil filling of the drilling bucket reaches saturation, the drilling rig stops pressurized drilling, the power head remains stable, and the winch system is operated to lift the drill rod and the drilling bucket, smoothly moving the drilling bucket out of the hole. When the drilling bucket reaches the designated unloading height, open the bottom opening and closing structure of the drilling bucket, automatically dump the internal rock and soil debris, and complete a single soil extraction and unloading operation. After unloading is completed, the drilling rig rotates the machine body, realigns the drilling tools with the center of the pile hole, lowers the drill rod to the bottom of the hole, and starts the pressurized rotary drilling program again. The core cycle logic of the normalized construction of rotary drilling rigs is to continuously excavate downwards and gradually deepen the depth of the pile hole through the reciprocating cycle operation of "drilling soil taking bucket unloading reset".

Hole wall protection to avoid construction hazards

During the entire drilling cycle, hole wall protection runs through the entire process, which is a key link in ensuring the quality of borehole formation. During the construction process, mud wall protection technology is adopted simultaneously for loose sandy soil, abundant groundwater and other prone to collapse formations. A dense mud protective film is formed on the hole wall to balance the water and soil pressure inside and outside the hole, preventing soil collapse and diameter reduction of the hole wall. At the same time, the operation mode of the drilling rig drilling at a constant speed and smoothly lifting and lowering the drilling tools can minimize the erosion and disturbance to the hole wall to the greatest extent. Dynamic protection throughout the process can effectively solve the construction difficulties of pile foundations in complex geological conditions, ensuring uniform hole diameter and regular hole walls, and providing qualified construction conditions for subsequent steel cage placement and concrete pouring.

Clean and verify the formation of the hole, and complete the overall hole formation

After the drilling tool reaches the designed pile hole depth, stop the drilling cycle operation and enter the final hole cleaning and hole verification stage. Firstly, the residual sediment, floating soil, and gravel at the bottom of the hole are cleaned using a dedicated hole cleaning drill bucket to reduce the thickness of sediment at the bottom of the hole and ensure that the bearing capacity of the pile foundation meets the standard. After the hole cleaning is completed, the construction personnel use professional testing equipment to verify the core parameters of the pile hole diameter, depth, verticality, and wall flatness, ensuring that all indicators comply with the pile foundation construction specifications. After the parameter verification is qualified, the drilling operation of the rotary drilling rig is officially completed, and the formed pile hole can directly enter the subsequent pile foundation pouring construction process.