During construction, slippage at the bottom of the hole, making drilling difficult, is a common problem. SDLQ rotary drilling rig editors have analyzed the following five specific causes:#hydraulic pile driver#
01 Mud Causes
Slippage is common when drilling on clay substrates. This is because the mud increases in concentration and specific gravity during repeated use, causing the drill bit to float. The drill cannot reach the bottom of the hole. When pressure is applied to the bottom, the high speed of the drill bit causes the mud to have a secondary effect, lubricating the clay at the bottom of the hole and the cutting surface of the drill teeth. Slippage is caused by the mud. This problem is relatively easy to address. Reduce the mud density. Once the drill bit reaches the bottom of the hole, manually control the rotation speed of the power head and gradually increase the pressure at 9 rpm. This is a problem with a wear-resistant rod drill.
02 Drill Tool Causes#hydraulic pile driver#
Slippage can be caused by a variety of factors, including misalignment between the drill tool and the drill rod, a drill tooth angle less than 45 degrees, an improper center cone, overly dense tooth arrangement, and severe wear of the drill tool. 03 Geological Causes
Some geological formations are mudstone, which has a low compressive strength of only around 550kPa. However, it is dense and prone to slippage when exposed to water. Addressing mudstone slippage requires thoroughly addressing the three causes mentioned above, as well as careful attention to drill bit selection. This requires the operator to possess sufficient experience in drilling techniques.
04 Improper Operational Techniques
For example, overcutting during drilling can force the bottom of the hole to flatten, causing slippage in the next drill. Failure to fully close the bucket during drill bit lifting, allowing a large amount of soil to fall to the bottom of the hole, can also cause slippage. Excessive starting speed can cause drill bit jamming. Proper operation and drill bit selection are the most fundamental causes of slippage.
05 Other Causes
Excessive speed of the power head, lack of fast or slow speed settings, structural issues, insufficient pressure, and the deflection of the drill pipe over time can also cause slippage.#hydraulic pile driver#
