Galvanized steel pipes for urban infrastructure construction, building construction, bridge and tunn

Grouting steel pipes, commonly known as steel flower tubes, grouting small guide pipes, advanced support pipes, and pile foundation grouting pipes, are specialized perforated steel pipes used in geotechnical engineering to reinforce soil layers, stop water seepage, and provide advanced support through high-pressure injection of cement slurry.

The process involves: 1. Driving the steel pipe into the soil layer or pile hole; a high-pressure grout pump then injects dual-liquid cement-silicate grout through overflow holes in the pipe wall into soil fractures. 2. After grout solidification, a composite pile body consisting of grout veins and the steel pipe is formed, filling voids and bonding loose gravel. 3. The steel pipe itself also functions as an anchor rod or micro-pile, providing rigid support force, thereby doubling the bearing capacity of surrounding rock and foundations.

Types: • Premium (Tunnel Advanced Support Preferred): 20# Seamless Steel Pipe (good toughness, easy to taper and drill, ideal for tunnel advanced support) • Economic: Q235B Straight Seam Welded Pipe (for post-grouting of piles and low-pressure foundation grouting) • High Strength: Q355B (for broken rock formations and high-pressure deep-hole grouting)

Outer Diameter (OD) Series: • Post-grouting of Piles: Φ25, Φ32, Φ42, Φ48, Φ50 • Tunnel Advanced Small Guide Pipes (High Frequency): Φ42, Φ48, Φ60 • Large Pipe Pile Support: Φ76, Φ89, Φ108, Φ114, Φ127 • Dams / Deep Excavations: Φ146, Φ168 and above

Wall Thickness: • Shallow Low-Pressure Grouting: 2.5–3.5mm • Conventional Tunnels / Excavations: 3.5–5.0mm (most common: Φ42×3.5, Φ48×4) • High Pressure, Deep Holes, Broken Zones: 6–10mm (e.g., Φ108×8 pipe pile)

Features: 1. Tapered Tip: Front end is formed into a conical shape via stamping or machining for easy insertion into soil; tip is spot-welded to seal. 2. Overflow Holes: Perforated in a plum blossom or spiral pattern on the pipe wall, with hole diameter 6–10mm and spacing 15–30cm. 3. Grout Stopper: Geotextile or rubber sleeve wrapped around outside of grout holes to prevent backflow of mud and sand clogging. 4. Connection Methods: Casing welding, threaded coupling, bevel butt welding for extension; standard single length: 3m/4.5m/6m, custom lengths available.

Applications: 1. Advance pre-support for rail transit, highway, and railway tunnels. 2. Post-grouting of bored piles for high-rise buildings and bridges. 3. Slope reinforcement, curtain waterproofing, and quicksand treatment for deep excavations. 4. Seepage prevention, cave/void filling, and subgrade settlement treatment for reservoir dams. 5. Crack sealing, leakage repair, and rock mass reinforcement for underground utility tunnels and civil air defense projects.