Shaanxi Flourish Industrial Co., Ltd.'s Circular Tunnel Steel Formwork revolutionizes tunnel construction with its "full-section precision + earth-pressure resistance" system-solving "roundness deviation" and "tunnel-environment vulnerability" of generic steel formworks. Crafted from high-strength Q355ND steel (optimized for tunnel loads), it delivers ±2mm roundness precision for 3-10m diameter tunnels, 100kN/m² earth-pressure resistance, and 40% faster assembly-trusted by global highway, railway, and municipal tunnel contractors.
Core Advantages (Tunnel-Exclusive)
1. Full-Section Circular Precision Forming
Patented "segmented arc calibration" design: 8-12 arc segments (per tunnel diameter) with built-in laser levelers, ensuring ±2mm roundness precision. Unlike split formworks (roundness error ≥5mm), it eliminates "egg-shaped" tunnels-critical for tunnel ventilation and traffic flow. The arc surface finish ≤Ra 6.3μm (smooth, no concrete burrs), reducing post-construction grinding cost by 80%.
2. High Earth-Pressure Resistance Structure
"Radial rib + circumferential bracing" system (radial rib 16mm thick, spacing 300mm; circumferential bracing 12mm thick): Withstands 100kN/m² earth pressure (equivalent to 10m-deep soil load) and 50kN/m² concrete lateral pressure. 6-point pressure test shows no deformation under 120% rated load-outperforming bridge pier formworks (not designed for tunnel radial earth pressure).
3. Tunnel-Environment Durable Coating
85μm hot-dip galvanizing (full surface) + 15μm polyurethane coating (inner tunnel surface): Resists 95% humidity (tunnel dampness) and 2000h salt-spray (coastal tunnels), preventing rust in dark, moist tunnel conditions. Service life ≥8 years (250+ reuses)-double that of road guardrail formworks (not adapted to tunnel humidity).
4. Modular Rapid Assembly for Tunnel Space
Lightweight arc segments (single segment ≤50kg, diameter 5m) + quick-lock bolts (15s/piece) enable 3 workers to assemble 20m tunnel formwork daily-40% faster than traditional bolt-connected types. Segmented design fits narrow tunnel entrances (≥3.5m width), no need for large crane hoisting (saves $2000/day rental).
5. Dust-Proof & Concrete-Leakage Prevention
Rubber sealing strips (embedded in arc segment joints) reduce concrete leakage to ≤0.3% (vs. 3% for ordinary formworks). Dust-proof coating on formwork surface (easy to clean) avoids concrete contamination from tunnel dust-reducing maintenance time by 30%.
Product Specifications
1. Material & Performance
Steel Grade: Q355ND (yield strength 355MPa, tensile strength 470-630MPa, low-temperature impact resistance ≥34J at -40℃)
Coating: 85μm hot-dip galvanizing + 15μm polyurethane coating, salt-spray resistance ≥2000h, humidity resistance ≥95%
Precision: Roundness error ±2mm, surface finish ≤Ra 6.3μm, linear error ≤3mm/10m
Load-Bearing: Earth pressure 100kN/m², concrete lateral pressure 50kN/m², deflection ≤2mm (10m diameter tunnel)
Reusability: ≥250 times, service life ≥8 years (inland tunnels) / ≥6 years (coastal tunnels)
2. Modular Components
Arc Segment: Thickness 8/10mm (optional), 8-12 segments per tunnel (diameter 3-10m), size 1500×2000mm (arc length)
Quick-Lock Bolt: Stainless steel, M20×80mm, service life ≥500 uses
Rubber Sealing Strip: Nitrile rubber, 10×20mm (joint width), high elasticity (no deformation after 100 uses)
Laser Leveler: Built-in, accuracy ±0.5mm/m, battery life ≥8 hours
3. Adaptation Parameters
Tunnel Diameter: 3-10m (customizable for 10-15m large-diameter tunnels)
Tunnel Length: Unlimited (modular extension via arc segments)
Concrete Grade: C30-C60 (common for tunnel linings)
Working Environment: Temperature -30℃~50℃, humidity ≤95%, dust concentration ≤10mg/m³
Application Scenarios
1. Highway Mountain Tunnel
A 5km mountain tunnel (diameter 6m) used 250 sets of formwork. Full-section precision (±2mm) ensured smooth traffic flow; radial rib structure withstood 90kN/m² mountain earth pressure-no deformation during construction. Modular assembly cut 30 days off the 90-day schedule.
2. Coastal Railway Tunnel
A 3km coastal tunnel (high salt fog) adopted our formwork's double-coating system. After 4 years of use, formworks remained rust-free; rubber sealing strips reduced concrete leakage to 0.2%, avoiding $25,000 rework cost.
3. Municipal Water Tunnel
A municipal water tunnel (high humidity, diameter 4m) used our dust-proof formworks. Easy cleaning of tunnel dust saved 2 hours daily; 250+ reuses covered 3 water tunnel projects, reducing procurement cost by 65%.
FAQ
1. Can it fit tunnels larger than 10m in diameter?
Yes-we provide "large-diameter extension kits" (custom arc segments + reinforced ribs) to support 10-15m diameter tunnels, with roundness precision still ±3mm.
2. How is it different from circular bridge pier formwork?
Bridge pier formwork focuses on vertical load (no radial earth-pressure design), while ours has radial ribs to resist tunnel soil pressure; our double-coating system is also more resistant to tunnel humidity (bridge formworks rust in 3 years in tunnels).
3. What's the delivery time for custom diameters?
Standard diameters (3-10m): 20 days for 100 sets; custom diameters (10-15m): 30 days, no extra mold cost.
Choose Shaanxi Flourish's Circular Tunnel Steel Formwork-tunnel-exclusive, not repurposed bridge or road formwork-for precise, stable, and efficient tunnel lining construction!
