A steel flower pipe is a type of pipe with several small holes processed on its surface, mainly used for grouting, drainage and other engineering purposes. The following is a detailed introduction to it:

Structural Composition

Main Steel Pipe: Seamless steel pipes are usually used, with common specifications of 48-108mm in diameter and 3-6mm in wall thickness. Galvanized steel pipes or high-strength alloy steel pipes are used in some special scenarios to improve corrosion resistance.

Grouting Holes and Grout Overflow Structure: A pair of grout outlet holes with a diameter of 4-6mm are drilled every 10-15cm along the axial direction, arranged in a spiral or plum-blossom pattern. The diameter of the holes within 50cm at the bottom is increased to 6mm, and no holes are drilled in the range of 1-2m at the top to prevent grout leakage. Some steel flower pipes are welded with angle steel plates or steel bar barbs on the outer wall of the steel pipe to avoid blockage of the holes and enhance the uniformity of grout diffusion.

Connection and Sealing Components: Connection methods include threaded sleeve connection, flange or connecting plate connection, etc. The bottom is sharpened and welded with an end-sealing steel plate to form a pile tip shape, which is convenient for driving into the soil and reducing resistance. The holes are temporarily sealed with plastic tape, and the tape breaks to release the grout during grouting.

Auxiliary Reinforcement Structure: Steel hoops or centering frames are welded every 1-2m along the length of the steel pipe to ensure that the steel pipe is centered and the thickness of the grouting protection layer is ≥2cm. In some designs, threaded steel bars are inserted into the steel pipe, or a steel mesh is attached externally and combined with the shotcrete surface layer to form a composite stress system.

Working Principle

Through the synergy between the steel pipe and the grout, soil reinforcement, structural stability and anti-seepage waterproofing are achieved. Under pressure, the grout penetrates, splits, compacts and cements the surrounding soil through the holes of the steel flower pipe. The steel pipe itself acts as a micro-pile, providing bending stiffness after being embedded in the soil, and forming a "pile-soil" composite body with the consolidated soil to improve the shear strength.

Application Fields

Tunnel Engineering: Used for the reinforcement and waterproofing of tunnel linings. By embedding steel flower pipes in the tunnel lining, the bearing capacity and waterproof performance of the tunnel lining can be improved.

Bridge Engineering: Mainly used for the reinforcement and maintenance of bridges. Embedding steel flower pipes in the bridge structure can reinforce and strengthen the bridge, improving its bearing capacity and service life.

Subway Engineering: Applied for the waterproofing and reinforcement of subway tunnels, which can effectively prevent groundwater leakage and tunnel deformation.

Expressway Engineering: Utilized for the reinforcement and drainage of roadbeds, which can enhance the bearing capacity and stability of roadbeds and prevent water accumulation on the road surface.

Advantages

High Strength: It can withstand high grouting pressure, lateral soil load and external impact force.

Good Grouting Effect: Through reasonable hole position design and connection sealing methods, the grout can diffuse evenly, achieving effective reinforcement of the soil.

Strong Adaptability: Different materials, specifications and structural forms can be selected according to different engineering geological conditions and construction requirements.