This kind of construction method refers to the construction method of burying the steel pipe piles with side protrusions (ribs) in the cement-soil column, and integrating the two to form a composite pile. The so-called cement-soil column is a mixture of cement slurry and soil with a poor mix ratio injected from the cobalt head while drilling with a special drill bit on the pile position.
The diameter of the synthetic steel pipe pile (that is, the diameter of the cement-soil column) is 600~1500mm, which is 200~400mm larger than the outer diameter of the steel pipe, and the applicable pile length is less than 70m. (gravel) layer of stone. This type of pile has the advantages of high bearing capacity, low vibration, low noise and less construction residue.
(1) Simultaneously burying the characteristics of the synthetic steel pipe pile construction method The special drill bit at the bottom of the steel pipe pile is provided with expandable drilling wings and stirring wings and a wing plate to prevent co-rotation; while drilling, the cement slurry is sprayed from the drill bit. , It is mixed with soil to form a cement-soil pile, and the side and protruding steel pipe piles are buried in the cement-soil column at the same time without loosening the soil layer around the pile.
(2) The characteristics of the method of burying synthetic steel pipe piles afterward are to set up a steel casing under the top of the pile. In the case of a stabilized liquid wall, the special drill bit’s drilling stirring wing (right rotation) is used to drill to a certain depth, and the drilling is performed while drilling. The sprayed cement slurry is mixed with the soil; after reaching the bearing layer of the pile end, the sprayed cement slurry is stirred and mixed with the pile end by the stirring wing (turn left); The pile is buried in the cement upper column; finally, the steel casing is pulled out to form a pile.
4.5 Pre-drilled steel pipe pile construction method
The pre-drilled steel pipe pile construction method refers to first drilling a hole with a size almost the same as the outer diameter of the steel pipe pile on the pile position (soil dumping type) and relaxing only the soil layer in the pile position (no soil dumping type), and then The steel pipe pile is inserted to sink it to the bearing layer of the pile end, and then the pile end treatment method (final strike method, cement slurry injection method and enlarged head reinforcement method) is used to obtain a construction method with a larger bearing capacity. For soil-draining pre-drilling, depending on the hydrogeological conditions, drilling rigs can be used to directly form holes, or drilling fluids such as clean water, mud or cement slurry can be injected into the holes from the drill bit while drilling. In the case of pre-drilling without soil dumping, drilling fluids such as bentonite mud and cement slurry are usually injected from the drill bit while drilling to make it mix with soil and sand without soil drainage.