Suggestions for using a piling roller bit core barrel.
1. Clean the bottom of the pile foundation hole before drilling.
Before drilling the core barrel into the hole, make sure there are no foreign objects at the bottom of the hole. If there are foreign objects, clear and salvage them before drilling. After each lifting of the roller bit core barrel, it is necessary to observe whether the roller bit core barrel has any parts falling off. If there are any falling parts, please salvage them in time.
2. The drilling speed should not be too fast.
The drilling speed should not be too fast, and the core barrel should slowly contact the bottom of the hole to avoid the bottom of the hole being inclined or pressing on isolated rocks. Excessive instantaneous pressure blunts the bearing; before contacting the bottom of the hole, the roller bit core barrel is in a low-speed rotation state.
3. Pressurize after the crushing surface is stable.
After the core barrel contacts the bottom of the hole, it works at a low speed and low drilling pressure. After the flat crushing annular surface is formed, the speed gradually increases from slow to normal. The pressure of the roller bit core barrel gradually changes from self-weight pressurization to inching pressurization.
4. Pressure range and pressurization method.
The drilling pressure of the core barrel cannot be too high, and the pressure can only be increased by jogging. The load of each rock roller bit is 3-5 tons. The operator of the rotary drilling rig can calculate the total weight of the drill rod and core barrel, and determine the pressure range according to the number of rock roller bits.
5. The rotation speed of the core barrel per minute.
Roller bit core barrel revolution table (rev/min).
| Core barrel diameter (mm) | Number of revolutions per minute (lower limit) | Number of revolutions per minute (lower limit) |
| 800 | 13 | 27 |
| 1000 | 10 | 21 |
| 1200 | 9 | 18 |
| 1400 | 7 | 15 |
| 1600 | 6 | 13 |
| 1800 | 6 | 12 |
| 2000 | 5 | 10 |
| Note: 1.The Core barrel revolutions in the table above are calculated based on the 50-100 revolutions per minute of a 216mm tricone drill bit.2. Each rock roller bit has a load bearing capacity of 3-5 tons, and the maximum drilling pressure and speed cannot be used at the same time. | ||
