Application of Rotary Drilling Rigs in Entire Sand Layers#different types of drilling rigs#
Drilling piles in quicksand layers has always been a significant challenge for pile operators. Preventing landslides during pile driving is crucial. Kaiao rotary drilling rigs effectively solve the problem of landslides during pile driving in quicksand layers.
1. Process Flow
The main processes for bored pile construction include: surveying and setting out, hole formation, reinforcement cage fabrication, transportation and installation, concrete mixing, concrete pouring for pile formation, and post-grouting.
2. Drill Rig Positioning
The drilling rig can only be positioned after the pile location has been correctly verified and the casing installation meets the requirements. The drilling rig must be accurately positioned, horizontally, vertically, and stably. The center lines of the drilling rig guide rod, rotary table, and casing should be aligned.#different types of drilling rigs#
3. Mud Preparation
During the construction of bored piles, to prevent hole collapse, stabilize the water level inside the hole, and facilitate the carrying of drill cuttings, bentonite is used to prepare mud for wall protection. Mud wall support utilizes the pressure difference between the mud and groundwater to control water pressure, ensuring borehole stability. Therefore, the specific gravity of the mud plays a crucial role in maintaining this pressure difference. If the specific gravity of the mud in the borehole is too low, the mud wall support will easily fail to prevent soil collapse; if the specific gravity is too high, it can easily cause blockages in the mud pump and even make concrete replacement difficult, compromising the quality of the pile. To fully utilize the role of the mud, the selection of its parameters is extremely important. This requires that, in actual engineering construction, the mud parameters in different soil layers be reasonably controlled according to the specific conditions of the project.
4. Drilling and Hole Formation
During hole formation, construction should proceed according to the parameters determined during trial construction. A dedicated recorder should record various parameters of the hole formation process, such as drill rod addition, drilling depth, geological characteristics, mechanical equipment damage, and obstacles. Records must be meticulous, timely, accurate, and clear.
The inlet and outlet mud parameters must be tested as required, and adjustments should be made promptly if any exceedances are found. 5. First Hole Cleaning: Test the mud parameters and adjust them promptly if any exceed the standards. Then, lower the drill bit to the bottom of the hole to sweep away sediment. Thorough cleaning is essential. After cleaning, conduct a self-inspection and, together with the supervising engineer, measure the hole depth as a basis for measuring sediment after the second cleaning.
6. Reinforcing Cage Fabrication and Installation: A significant advantage of rotary drilling rigs is their rapid hole formation and minimal sediment at the bottom. Therefore, by taking appropriate measures during the fabrication and installation of the reinforcing cage to prevent it from scratching the hole wall, the thickness of sediment can be significantly reduced, effectively preventing hole collapse. This requires strict control over the fabrication of the reinforcing cage, focusing on its outer diameter and straightness, and ensuring that the welding quality of the main reinforcement laps and longitudinal and transverse reinforcement intersections meets design requirements. For this purpose, the placement of the reinforcing cage protective layer spacers must be checked. In this project, cylindrical mortar spacers are used, placed in groups of four every 4 meters along the reinforcing cage, evenly spaced at 90° angles. This prevents the cage from colliding with the borehole wall and ensures a uniform concrete cover and correct positioning of the reinforcing cage within the pile.
The reinforcing cage should be hoisted from three points to maintain alignment of the cage's axis. During insertion into the borehole, it must be kept vertical at all times, aligned with the borehole position, and lowered slowly and gently, maintaining stability and avoiding collisions with the borehole wall. If obstruction is encountered, the cause should be immediately identified; shaking and forced impact are prohibited during lowering.
7. Lowering the tremie pipe: The tremie pipe must undergo regular watertightness tests. Before lowering the tremie pipe, check for air leaks, water leaks, and deformation, and ensure that sealing rings are in place. The tremie pipes should be lowered sequentially. After all tremie pipes are inserted into the borehole, they should be placed at the bottom to verify the pipe length and borehole depth. Then, lift them 30-50 cm for secondary borehole cleaning.
8. Secondary Hole Cleaning: Test the inlet and outlet mud parameters and adjust them to the parameters determined in the construction organization design. Use a steel wire measuring rope to measure the sediment at the bottom of the hole, generally controlling it within ≤10cm. If it exceeds the standard, adjust it promptly. If it exceeds the standard, insert the drill bit into the bottom of the hole to sweep away the sediment. Hole cleaning must be thorough.
Tengzhou Kaiao Machinery Co., Ltd. is committed to the production and sales of small rotary drilling rigs, crawler pile drivers, long spiral drilling rigs, diesel hammer pile drivers, and excavator-converted rotary drilling rigs. Adhering to the principles of pragmatism, progress, and innovation, the company has been working in the small rotary drilling rig market for over 10 years, and its product quality has won widespread praise from customers.#different types of drilling rigs#
