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

Equipment positioning and precise alignment in the early stage

Before the formal construction of the rotary drilling rig, it is necessary to complete the site leveling, equipment leveling, and precise alignment of the pile positions, which are the basic processes to ensure the accuracy of drilling. During construction, operators adjust the overall levelness of the machine through the hydraulic leveling system to avoid quality issues such as hole displacement and hole wall inclination caused by tilt deviation. At the same time, relying on the body positioning system to calibrate the design pile position, adjust the vertical alignment of the drill rod and bucket with the pile center, fix the operating position of the body, and prevent equipment displacement during the construction process. This stage strictly controls the verticality and point accuracy, adapts to the construction standards of various projects such as bridges, buildings, and municipal pile foundations, and lays a solid foundation for stable drilling operations in the future.

Rotary pressurized formation drilling operation

After precise positioning is completed, the rotary drilling rig enters the core drilling stage, relying on the hydraulic power system to achieve efficient rock breaking and soil extraction. The equipment lowers the drill rod and bucket through the main winch, and uses the body pressure device to provide vertical pressure to the drilling tool. With the help of the power head, the drill rod continues to rotate, driving the bottom bucket cutting teeth to cut and break soil and rock layers. For different geological conditions such as clay, sand, gravel layers, weathered rocks, etc., the equipment can adapt to the characteristics of the strata by adjusting the rotation speed and pressure. Soft soil strata are quickly excavated at low speed and light pressure, while hard rock strata are crushed layer by layer at high pressure and low speed. The crushed soil will be directly stored inside the drilling bucket, achieving synchronous drilling and soil extraction operations, greatly improving the efficiency of pile foundation construction.

Lifting bucket for soil unloading and cyclic drilling

When the interior of the drilling bucket is filled with debris and reaches the rated drilling depth, the equipment stops rotating and pressurizing, starts the main hoist to lift the drill rod and drilling bucket, and smoothly lifts the drilling tool out of the hole. The rotating platform of the machine body drives the drilling bucket to rotate to the construction waste area, and opens the bottom plate of the drilling bucket through the hydraulic opening and closing mechanism, automatically removing the accumulated slag inside and completing a single soil extraction operation. After the soil unloading is completed, the drilling rig rotates and resets, and the drilling bucket is aligned with the pile hole and vertically lowered again. The operation cycle of pressurization, rotation, soil extraction, bucket lifting, and soil unloading is repeated. Through multiple reciprocating operations, continuously excavating the strata downwards, gradually advancing the depth of the pile hole, and adapting to the construction requirements of different pile lengths.

Bottom trimming and verticality calibration of hole diameter

When the drilling depth approaches the design elevation, the equipment stops deep excavation and enters the hole type adjustment and calibration process. Continuous cyclic drilling can easily cause problems such as uneven bottom of the hole, local deviation of the hole diameter, and slight inclination of the hole wall, which will affect the subsequent installation of steel cages and the quality of concrete pouring. At this time, the drilling rig reduces its rotation speed and uses the drilling bucket to perform flat sweeping and trimming on the bottom of the hole, polishing and leveling the rock and soil layers at the bottom of the hole. At the same time, the overall verticality of the pile hole is calibrated, and irregular parts of the hole wall are corrected. This process can effectively ensure that the roundness and verticality of the pile hole comply with engineering specifications, eliminate construction errors, and improve the structural stability of the formed pile foundation.

Cleaning the hole and completing the hole forming process

After the finishing work is completed, it enters the final hole cleaning and finishing stage, marking the formal formation of the pile hole. Construction personnel use specialized hole cleaning tools to clean the residual floating soil, gravel, and sediment at the bottom of the hole, thoroughly removing impurities inside the hole and avoiding excessive sediment that affects the bearing capacity of the pile foundation. After the hole cleaning is completed, a comprehensive inspection of the depth, diameter, verticality, and bottom flatness of the pile hole should be carried out. Once all indicators are met, the drilling operation can be terminated. At this point, the rotary drilling rig has completed the complete drilling process from early alignment, layered drilling, cyclic soil sampling, hole repair and calibration to hole cleaning and finishing. The formed pile holes can directly enter the subsequent pile foundation pouring construction process.