I. Structural Characteristics
The anti-settlement manhole cover adopts an integral casting process and reinforced structural design. Key technical features include:
- Material: Ductile Iron QT500-7 (Tensile strength ≥500MPa)
- Bottom ring-shaped support rib plate (Thickness ≥15mm)
- Three-point elastic locking system (Load-bearing capacity ≥400kN)
- Polymer composite sealing strip (Temperature resistance range: -40℃ to 120℃)
II. Mechanism of Action
- Load Distribution Mechanism
By expanding the bearing area (35% larger than traditional covers) and optimizing stress distribution, vehicle dynamic loads are effectively transferred to the entire manhole structure. Test data show a 62% reduction in asphalt layer stress around the manhole under a standard 100kN axle load. - Displacement Control Function
The flange interlocking structure (clearance ≤1.5mm) combined with anchor bolts providing 50kN pre-tightening force limits vertical displacement to ≤0.5mm, effectively preventing progressive settlement under repeated loading. - Interface Synergy
The elastic sealing device (compression set ≤8%) forms a flexible transition layer with the asphalt pavement. Its dynamic compensation mechanism (compensation ≥3mm) eliminates interface damage caused by thermal differentials.
III. Technical Advantages
- Extended maintenance cycle: 30-year service life, reducing repair frequency by 80%
- Improved road quality: Manhole perimeter damage rate reduced to 0.3 occurrences/year/km
- Safety benefits: Nighttime reflectivity >450 mcd/lx/m²; Anti-theft rating meets EN124 D400 standard
IV. Engineering Application
At Shanghai Pudong Airport runway renovation project, implementation reduced:
- International Roughness Index (IRI) from 3.2 m/km to 1.8 m/km
- Differential settlement in wheel track areas to ≤1.2mm
Meeting ICAO 4E classification standards.