How To Choose The Length of The Drill Pipe for Second-hand Rotary Drilling RIGS Used in Long Pile Construction?

In the construction of long piles, the selection of the length of the drill pipe of the second-hand rotary drilling rig directly affects the construction efficiency and the quality of the pile. Choosing a short length may result in the failure to reach the designed pile depth, while choosing a long length may increase the equipment load and operational risks. Therefore, a scientific judgment should be made by combining multiple factors.

1. Determine the foundation length based on the designed pile depth: The total length of the drill pipe should be greater than the sum of the designed pile depth and the height of the drill rig's own mast. Generally, an operation allowance of 1-2 meters should be reserved to avoid the inability to complete the pile construction due to insufficient length. At the same time, attention should be paid to the possible wear of second-hand drill pipes. The reserved length should be appropriately increased to ensure the actual usage requirements.

2. Select the appropriate specifications based on the hardness of the stratum: In soft soil, sand layers and other loose strata, slightly shorter drill pipes can be chosen in combination with high-frequency drilling. If encountering rocks or hard soil layers, longer drill pipes should be used in combination with high-strength drilling tools. By increasing the drilling torque, it is ensured that the hard layer can be penetrated. For second-hand drill pipes, the strength of the pipe body should be checked in advance to see if it meets the operation requirements of hard strata.

3. Refer to the matching of the rated capacity of the drilling rig: The rated lifting force and torque of different models of second-hand rotary drilling RIGS vary. It is necessary to select the appropriate drill pipe length to avoid equipment failure caused by overloading operation. For instance, small drilling RIGS are suitable for short drill pipes of 15 to 20 meters, while medium-sized drilling RIGS can be equipped with drill pipes of 20 to 35 meters. When purchasing, it is necessary to verify whether the parameters of the drilling rig are compatible with the specifications of the drill pipes.

4. Consider the space limitations of the construction site: If the construction site has height restrictions such as high-voltage lines and buildings, the drill pipe should be selected based on the actual space height of the site to avoid the drill pipe being too long to be able to lift or rotate normally. If the second-hand drill pipe needs to be cut and adjusted in length, it should be operated by professionals to ensure the stability of the pipe structure after cutting.

5. Check the wear and accuracy of second-hand drill pipes: When purchasing second-hand drill pipes, measure the actual length of each section of the drill pipe and check the degree of wear at the joints. If there are problems such as deformation and rust, it may lead to a shortening of the actual effective length. At the same time, appropriately compensate for the length deviation when choosing, and test the smoothness of the drill pipe's extension and contraction to avoid affecting the construction efficiency.

6. Reserve space for subsequent construction adjustment: If the project has multiple batches of construction requirements with different pile depths, when choosing drill pipes, slightly longer specifications can be given priority, and adjustable drill tools can be used to reduce the cost and time of subsequent drill pipe replacement. At the same time, the bearing allowance of the second-hand drill pipe needs to be calculated to ensure that the safety operation requirements can still be met when adjusting the pile depth.

In conclusion, when choosing the length of the second-hand rotary drilling rig drill pipe for long pile construction, it is necessary to take the designed pile depth as the basis and comprehensively consider factors such as the stratum, equipment, and site. At the same time, the actual condition of the second-hand drill pipe should be strictly inspected. Only in this way can the operation efficiency and pile quality be improved under the premise of ensuring construction safety.