Bottom support is the so-called surface contact. Rotary drilling mainly relies on the drill teeth to condense pressure and torque, and use linear or point tools to cut, crush or grind the geology. Once bottom support occurs, it will lead to heavy load and low drilling efficiency. Therefore, it is very necessary to judge and analyze the cause of bottom support in time.#hydraulic piling machine#
Regardless of the cause, bottoming out will result in power loss and increased resistance. So, what are the causes of bottoming out during rotary drilling? Are there any preventative measures? Below, our SDLQ rotary drilling rig editor will share with you the causes of bottoming out during rotary drilling:#hydraulic piling machine#
1. Drill Bucket Defects
Drill bucket defects can cause bottoming out, including: excessively high support plates, drill bit angles, worn drill bits, blind spots in drilling, and the size of the slag inlet.
2. Geological Factors
Bottom-out is most often caused by weathered, fully weathered, or strongly weathered rocks. Sedimentary rocks such as mudstone and sandstone can also cause bottoming out.
3. Drill Tool Selection
Drill tools should be selected based on the geology. For example, using a rock drill bucket with shorter cutters can easily cause bottoming out when drilling in cemented geology.
4. Operational Bottom-out
Operational Bottom-out is primarily caused by improper control of the single bucket penetration depth. For example, in certain geology or pile diameters, a single bucket penetration depth of 50 cm is common, but some operators insist on reaching 70 cm per bucket, which inevitably leads to bottoming out. Preventing Drilling Bottom-Out:
Drilling bottom-out can be overcome by first checking the single-bucket penetration depth on the display. Although mud layers offer little drilling resistance, as the amount of debris inside the drill bucket increases, resistance to the inlet increases. The sound of the planetary reducer on the power head changes with the resistance, so the penetration depth can be determined by listening to the sound. As drilling resistance increases, the power head speed also decreases, so the penetration depth can also be determined by the drill pipe speed. If geological changes are minimal, the drilling time and depth per bucket should be kept within a certain range. The single-bucket penetration depth in mud layers should be between 0.5 and 0.6 meters. When reversing and closing the bucket bottom, try to do so when drilling under load. This provides some resistance, preventing the bucket bottom from reversing with the drill pipe.#hydraulic piling machine#
