Construction technology of long spiral bored pile

1. Long spiral drilled cast-in-place piles generally use superfluid concrete, which has good flowability. Stones can suspend in the concrete without sinking, and there will be no segregation. It is easy to put it into a steel cage; (Superfluid concrete refers to concrete with a slump of 20-25cm)

2. The pile tip is free of loose soil, preventing common construction problems such as pile breakage, diameter reduction, and hole collapse, and ensuring construction quality easily;

3. Strong ability to penetrate hard soil layers, high single pile bearing capacity, high construction efficiency, and easy operation;

4. Low noise, no disturbance to residents, no need for mud wall protection, no pollution discharge, no soil squeezing, and civilized construction site;

5. High comprehensive benefits and relatively low engineering costs compared to other pile types.

6. The design calculation of this construction method adopts the dry drilling and grouting pile design method, and the design calculation index should adopt the dry drilling and grouting pile index (the index value is greater than that of the mud retaining wall drilling pile and less than that of the prefabricated pile).

2、 Scope of application:

Suitable for building foundation piles, foundation pits, and deep well support, suitable for fill layers, silt layers, sand layers, and gravel layers, as well as various soil layers with groundwater. It can be used to form piles in adverse geological conditions such as soft soil layers and quicksand layers. The pile diameter is generally between 500mm and 800mm.

3、 Process principle:

Long spiral drilling pile is a type of pile that uses a long spiral drilling rig to drill holes to the design elevation. After stopping the drilling, the concrete hole on the inner pipe drill bit is used to inject superfluid concrete. After injecting the concrete to the design pile top elevation, the drill rod is removed to press the steel cage into the pile body. When pouring concrete to the top of the pile, the poured concrete should exceed the top of the pile by 50cm to ensure the strength of the concrete at the top of the pile.