Rectangular Tunnel Steel Formwork

Shaanxi Flourish Industrial Co., Ltd.'s Rectangular Tunnel Steel Formwork is the industry's first "fully enclosed underground space optimization" solution-engineered exclusively for rectangular tunnels, addressing "full-section load balance" and "max usable space" pain points that U-shaped tunnel formworks (semi-open, side-pressure focused) cannot solve. Crafted from tunnel-optimized Q355ND steel, it delivers ±2mm linear precision for 2-8m wide/1.5-4m high fully enclosed tunnels, 95kN/m² multi-directional load resistance, and 35% faster assembly-trusted by municipal utility corridors, subway links, and underground roads globally.

1. Fully Enclosed Four-Panel Integral Structure

Unlike U-shaped formworks (semi-open, missing top panel, designed for water diversion with open top), this rectangular formwork features a fully enclosed four-panel system (top + bottom + two side walls). Patented "four-panel calibration locks" ensure ±2mm linear precision and 0.5° angle accuracy-eliminating "top-side gaps" that occur when repurposing U-shaped formworks for enclosed spaces. Usable space is maximized by 40% (vs. U-shaped tunnels of equal width), enabling simultaneous installation of multi-layer utility pipes (e.g., water, gas, electricity) in municipal corridors.

2. Multi-Directional Load Resistance (Top + Side + Bottom)

U-shaped formworks only resist lateral soil pressure and bottom water pressure (no top load design), but this rectangular formwork uses "16mm vertical ribs (side walls) + 14mm horizontal beams (top/bottom) + 10mm corner reinforcement plates" to withstand three types of loads: 95kN/m² lateral soil pressure, 45kN/m² top vertical load (from overlying soil/structures), and 30kN/m² concrete lateral pressure. In subway link projects, it avoids top-panel deformation (a common issue with modified U-shaped formworks), meeting the "zero settlement" standard for underground traffic facilities.

3. Full-Section Space Optimization for Enclosed Scenarios

U-shaped tunnels are limited to single-function scenarios (e.g., water diversion, narrow drainage) due to their semi-open design, while rectangular tunnels with this formwork support multi-scene integration:

 Municipal utility corridors: 3-layer pipe installation (top: electricity, middle: gas, bottom: water) via flat top/bottom panels (U-shaped formworks lack top space for upper-layer pipes).

 Underground pedestrian passages: 2.5m clear height (vs. U-shaped tunnels' 1.8m max) with smooth top/bottom for lighting/ventilation installation.

Space utilization efficiency is 50% higher than U-shaped tunnels of the same cross-sectional area.

4. Four-Corner Waterproof System (vs. U-Shaped Two-Corner)

U-shaped formworks only need waterproofing for two bottom-side corners (open top has no waterproof demand), but rectangular tunnels (fully enclosed) face water seepage risks at four top-side/bottom-side corners. This formwork uses "integrated nitrile rubber strips (15×30mm) + tongue-and-groove joints + waterproof mortar sealing" at all four corners, reducing leakage to ≤0.2% (vs. 5% when using U-shaped formworks for enclosed tunnels). In coastal utility corridors, it saves $30,000/km in waterproof repair costs.

5. Corner Waterproof & Leakage Prevention

Integrated corner rubber waterproof strips (15×30mm nitrile rubber) + tongue-and-groove panel joints: Reduce concrete leakage to ≤0.2% (vs. 3% for ordinary formworks) . This solves the key waterproof challenge of rectangular tunnel corners, avoiding $25,000/km waterproof repair costs in utility corridors . The strips are replaceable, ensuring long-term water tightness.

1. Installation Steps

Step 1: Level tunnel base → mark rectangular centerline (error ≤1mm)

Step 2: Install bottom panel → snap-lock side walls (laser level verification)

Step 3: Fix top panel to side walls → install corner waterproof strips + seal with waterproof mortar

Step 4: Apply water-based release agent → pour C30-C60 concrete (layer height ≤500mm)

2. Maintenance Tips

After demolding: Rinse with high-pressure water (remove concrete residue) → dry with air blower (avoid coating damage)

Weekly: Inspect waterproof strips for wear (replace if cracks appear)

Monthly: Lubricate snap-locks with anti-rust oil → check panel flatness

Annually: Touch up coating scratches (use matching epoxy-polyurethane paint)

1. Can U-shaped formworks replace rectangular ones for enclosed tunnels?

No-U-shaped formworks lack top panels (can't resist top load) and only waterproof 2 corners (4 corners of enclosed tunnels will leak). Repurposing them requires adding custom top panels (cost +30%) and extra waterproofing (time +50%), leading to project delays.

2. Why does rectangular formwork need 3-way load resistance?

Rectangular tunnels are fully enclosed (top covered by soil/structures), so they face top vertical load (U-shaped tunnels have open tops, no top load). 3-way resistance ensures structural safety-critical for public facilities like subway links and underground roads.

3. How is space efficiency better than U-shaped tunnels?

U-shaped tunnels waste top space (open design), while rectangular tunnels use full vertical space (e.g., 3-layer pipes in utility corridors). For a 6m wide tunnel, rectangular formworks provide 18㎡ usable area (3m high), vs. U-shaped's 12㎡ (2m high)-40% more space.

Choose Shaanxi Flourish's Rectangular Tunnel Steel Formwork-rectangle-specific, not repurposed circular/U-shaped formwork-for space-efficient, stable, and durable rectangular tunnel construction!